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MANUAL OF THE INFUSORIA.

VOLUME II.

" Our little systems have their day,

They have their day and cease to be ;
They are but broken lights of Thee,
And Thou, O Lord, art more than they."

TENNYSON, In Afemoriam.

MANUAL OF THE INFUSORIA:

INCLUDING A DESCRIPTION OF ALL KNOWN

FLAGELLATE, CILIATE, AND TENTACULIFEROUS PROTOZOA,

BRITISH AND FOREIGN,

AND AN ACCOUNT OF THE

ORGANIZATION AND AFFINITIES OF THE SPONGES.

BY

W. SAVILLE KENT, F.L.S., F.Z.S., F.R.M.S.,

FORMERLY ASSISTANT IN THE NATURAL HISTORY DEPARTMENTS OF THE BRITISH MUSEUM.

VOLUME II.

LONDON:
DAVID BOGUE, 3 ST. MARTIN'S PLACE,

TRAFALGAR SQUARE, W.C.
I88I-I882.

MANUAL OF THE INFUSORIA.

CHAPTER VIII.

SYSTEMATIC DESCRIPTION OF THE INFUSORIA-CILIATA.

Class IL CILfATA.

ANIMALCULES partly or more or less completely clothed with vibratile
cilia, which constitute the essential organs of locomotion and prehension ;
no supplementary lash-like appendages or flagella ; certain of the cilia
often modified in the form of setae, styles, or uncini ; occasionally pos-
sessing more or less distinct membraniform expansions ; a well-developed
oral and anal aperture mostly present.

With the class Ciliata we arrive at a group of the Infusoria with which micro-
scopists will feel comparatively at home, all its members being of relatively large
size, and for the most part very giants when set side by side with their flagelliferous
compeers described in the preceding volume. That no hard and fast line separates
the two groups from each other is nevertheless clearly illustrated by the series of
forms last described under the title of the Cilio-Flagellata, in many of which it
requires but the suppression of either the flagelliferous or ciliary appendages to con-
vert them into ordinary representatives of one or the other of the two leading ciliate
or flagellate infusorial classes. That the first-named group has been phylogenetically
derived from the Flagellata is by this annectant order fully demonstrated, its existence
at the same time assisting substantially in the establishment of an unbroken line
of increasingly complex Protozoic organisms, from the simplest Rhizopoda up to
the highest Ciliata. The probable lines of evolution by which these latter have
passed onwards into the Metazoic animal series will be presently discussed.

Among the numerous indications of augmented complexity manifested among
the members of the class now about to be introduced, the following may be
mentioned : — The cuticular or cortical element in the majority, if not all instances,
exhibits a much more complex composition. In by far the larger number of
instances it is delicately striate in a longitudinal direction, such striations conforming
with a distinct subdivision of its substance in the direction indicated into delicate,
highly elastic fibrillas, whose properties and function are closely akin to that of the
muscular tissue of the Metazoa, and has in consequence received the suggestive
name of the myophan layer. The oral aperture, or cytostome, with the Ciliata is,
excepting in the case of the endoparasitic Opalinidse, always more or less con-
spicuously developed, and is frequently supplemented by a complex horny buccal
apparatus, e. g. Prorodontidae, Dysteriidae, or it may be by an evertile proboscis, as in
Didinium. A modification in the first-named direction has been already notified in the
preceding volume in connection with the flagellate genera Astasia and Anisonema.
An anal passage or cytopyge, rarely recognizable in the Flagellata, is of almost uni-
versal recurrence among the Ciliata, being sometimes, as in Nyctotherus, so extensively
prolonged as, in conjunction with the oral aperture and pharyngeal tube, to constitute

VOL. II. B

474 CLASS II. CILIA TA.

a rudimentary alimentary tract. The rod-like bodies known as trichocysts,
recorded in but one or two doubtful instances as yet in connection with the
Flagellata (Chilomonas and Merotrichd), represent a common elementary factor of
the cortical layer of the Holotrichous Ciliata, and are next met with in the Metazoic
section of the Turbellaria. Already, in the cases of Anisonema grande and Entosiphon
sulcatus, attention has been directed to the exceptional composite rosette-shaped
contour of the contractile vesicle. Among the Ciliata this organ often exhibits a yet
higher degree of differentiation, not unfrequently (Spirostomum, Stentor, Ophrydiurti)
being produced peripherally into one or more extensive canal-like prolongations,
and may undoubtedly be accepted as foreshadowing the more or less complex
water-vascular, segmental, and ambulacral systems of the Metazoic classes of the
Turbellaria, Trematoda, Rotifera, higher Annelida, and Echinodermata. An im-
portant advance in the organization and physiology of the Infusoria Ciliata has
to be recorded in connection with all matters pertaining to the phenomena of
reproduction. Multiplication by longitudinal or transverse fission is, as among
the Flagellata. a common form of propagation. The encystment and breaking up of
the entire body-mass into sporular elements characteristic of the majority of the
Flagellata, and in which form of reproduction they exhibit decided vegetable
affinities, is of very rare occurrence among the Ciliata, the several Holotrichous
genera Colpoda, Otostoma, and Ichthyophthirius constituting the chief exceptions. In
place of this, new zooids with the Ciliata are usually produced by the subdivision
of the nucleus or endoplast into germinal elements, which are liberated independently
from the parent animal after the manner of the ova or embryos of the Metazoa. A
first progress in this direction has nevertheless been recorded of certain of the higher
Eustomatous Flagellata. The phenomenon of genetic union, or conjugation, directly
or indirectly associated with the reproductive faculties, exhibits likewise, among the
Ciliata, a decidedly advanced formula. While with the Flagellata, so far as is known,
the conjugative process is complete and permanent, according with the genetic
union or so-called zygosis of unicellular plants, this process, though similarly mani-
fested among certain Ciliata, such as the Vorticellidae, is more usually replaced by
an incomplete and transient conjugative act that corresponds more nearly with the
copulation of higher animals. Finally, while all Flagellata are essentially unicellular,
possessing but a single, and in almost all instances very simple, nucleus or endoplast,
among the Ciliata this structural element very commonly exhibits a highly com-
plex type of composition, and being in many instances represented in plurality,
demonstrates the further advance made by these organisms towards the condition
of multicellular beings.

The character and mode of distribution of the cilia yield reliable data for the
subdivision of this class into minor sections or orders, the following plan as here
adopted being in accordance with the one first introduced by Professor Stein in
the year 1857. While the more characteristic members of these several orders
yield features which permit of their natural and readily appreciated distinction,
intermediate forms occur in each such group indicative of their close relationship
and common design. Special reference is made to the more prominent of these
annectant or transitional types in the general description of the respective orders.

SYNOPSIS OF THE ORDERS OF THE INFUSORIA CILIATA.

Cilia distributed over the entire surface of the }

body, similar, or differing but slightly in > Order I HOLOTRICHA.

character.

Cilia distributed over the entire cuticular sur- 1

face; the oral series of conspicuously larger > ,, II HETEROTRICHA.

size.

Cilia not universally distributed, mostly limited
to a conspicuous circular or spiral adoral
wreath.

Locomotive cilia, confined to the inferior or

IIL .. PERITRICHA.

ventral surface of the body. / •• IV HYPOTRICHA.

CLASS II. CILIATA. 475

Before entering upon a systematic description of the Ciliata, it is worthy of
remark that until within a comparatively recent date the assemblage of organisms
included within this class were accepted by many eminent authorities as possessing
the only sound claim to the title of the Infusoria. The Flagellata, previous to
their more exhaustive scrutiny by recent investigators, were regarded for the most
part as Protophytes or the so-called zoospores of higher Cryptogamic plants, while
the Tentaculifera or Acinetidae were pronounced to be embryonic conditions only
of various Peritricha. Undoubtedly, this section of the Ciliata is one of the
largest and most important groups of the Protozoic sub-kingdom. In no other of the
equivalent subdivisions is histologic differentiation carried to such a marked extent ;
many of the higher forms being indeed so modified in this respect that they may
be unhesitatingly cited as furnishing the most complex expression of unicellular
organization. To the notice of the evolutionist, to an equal or even greater degree
than to the histologist, the Ciliate Infusoria deservedly commend themselves. It is
beyond question to the ranks of this extensive class that attention may be profitably
directed in the search after those ancient stock-forms or archetypes out of which
several of the more important groups or phyla of the Metazoa have been gradually
evolved. That the group of the Spongida does not, as maintained by some
contemporary authorities, furnish the long sought for interconnecting link between
the Protozoic and Metazoic series is substantially supported by the evidence
submitted by the author in Chapter V. of the preceding volume, in which it is
shown that, notwithstanding the plausibility and fascination of external appearances,
these organisms remain in all structural and developmental details thoroughgoing,
though peculiarly modified, Protozoa.

Already, in vol. i., p. 103 et seq., the homoplastic resemblances and possible
biogenetic relationship that subsist between the Ciliate and other Infusoria and the
Metazoic animal series have been discussed at some length. Further time devoted to
the consideration of this important subject, enables the author to greatly extend
the scope of the comparisons previously instituted, and to submit, in connection
with the woodcut illustrations on p. 477, and succeeding Genealogical Table, a
possible clue to the phylogeny of all of the more important Metazoic groups.
That the Holotrichous Ciliata may be consistently regarded as the archetypes
of the lower worms, has been frequently advocated, the likeness between the former
and the simpler Turbellaria being so marked, see woodcut, Figs. 3 and 4, that
many earlier authorities have proposed to include these Infusoria in the Annelidous
class ; K. M. Diesing, more especially, in recognition of such likeness, established
for their reception the new order of the " Prothelmintha." As related in vol. i. p. 26,
this authority included, however, in this order not only the Holotrichous Ciliata,
but, with the exceptions of the Vorticellidae and Stentoridae, all the Ciliate and
Flagellate animalcules. In addition to the resemblances subsisting between the
Holotrichous Infusoria and the Turbellaria, as manifested by their minute size and
corresponding form, by their entire and even ciliation, by their common possession
of trichocysts, and by the development in the members of the last-named group of
a water-vascular system, which may be regarded as a modification of the contractile
vesicles of the Infusoria, it may be mentioned that many of the Rhabdoccelous
Turbellarians multiply as do the Holotricha and other Infusoria by the simple
process of transverse fission. Taken collectively, the numerous collateral charac-
teristics cited yield almost overpowering evidence in favour of the biogenetic
relationship that is here advocated.*

Other Metazoic groups, in addition to that of the Turbellaria, would seem to
possess a substantial claim to an Holotrichous ancestry. In the sub-kingdom

* The near approach of the Ciliate Infusoria to the structural plan of the lower Turbellaria is
briefly indicated by Professor Huxley at p. 678 of his 'Anatomy of Invertebrated Animals,' ed.
1877; while, in a communication addressed to the author since the publication of the first two parts
of this Manual, this authority has more distinctly referred to the Holotricha as probably constituting,
in connection with the Turbellaria, the proper line of evolution from the Protozoic to the Metazoic
series. The Spongida are further alluded to as occupying in such case, with reference to the
Metazoa, a position equivalent to that held by the Tunicata in relation to the Vertebrata.

B 2

476 CLASS II. CILIATA.

Coelenterata, including the Corals, Sea Anemones, and Hydrozoa, the initial term
or larval form common to the group is an ovate, evenly ciliated body, or so-called
" Planula," woodcut, Fig. i , differing entirely from the parent organism, but in all ways
comparable with a mouthless Holotrichous Infusorium, as delineated at Fig. 2. In a
similar manner, the mostly endoparasitic Scolecida (Trematoda and Cestoidea) are
traceable to a like origin, many Trematodes, such as Monostomum, giving birth to
simple holotrichously ciliated embryos, while the aberrant Opalinidae, with reference
to their often highly differentiated organs of adherence and, in certain instances,
e. g. Anoplophrya prolifera, peculiar mode of reproduction, indicate a no very distant
connection with the Cestoidea. It is worthy of remark that while many of the higher
Annelids, Lumbricus and JVais, commence life as similar holotrichous infusorium-like
embryos, others, including the majority of the marine worms or Polychaeta, conform
for the most part, as do the larvae of the Echinodermata, with the Peritrichous
infusorial formula.

The order of the Heterotricha, whose members unite, in their plan of ciliation,
both the Holotricha and Peritricha, do not at present suggest any distinct Metazoic
affinities. It is at the same time perhaps deserving of attention that the ciliated
lappet-like appendages developed in the larval stage, or so-called " Pilidium " of the
Turbellarian genus Lineus, recall to some extent the ciliated lobes of the peristome
developed in the Heterotrichous genus Follicularia.

While, in the preceding volume, loc. cit. p. 103, a passing reference was made to the
affinities of the Peritrichous Vorticellidae with the Polyzoa, suggested by both L.
Agassiz and K. M. Diesing, such faint external likeness as subsists between the
adult structures and gave rise to such correlation, was not considered worthy of
serious entertainment. Since then, however, it has occurred to the present author that
from an entirely diverse standpoint the relationship suggested may be substantially
upheld. A first impression in this direction was derived from a recognition of the
close correspondence in external contour presented by the motile larvae or so-called
Trochospheres of the Polyzoon Alcyonidium gelatinosum, as delineated in a notebook
placed at the author's disposal by Mr. H. E. Forrest, and reproduced at PI. XXXI.
Fig. 53, and such a free Peritrichous Infusorium as Trichodina pediculus. Following
out this newly indicated clue, it was next found that the larval conditions of
numerous other Polyzoa, as recently figured and described by Barrois,* bear out in a
most remarkable manner the premised affinity. This last-named authority, further-
more, reduces all of the more or less modified embryos of this zoologic group to an
ideal type, see Fig. 1 1 of the accompanying woodcut, which, without a pre-existing
knowledge of its true import, would unhesitatingly be accepted as a slightly modified
example of the ordinary Vorticellidae, as given at Fig. 12. It is highly interesting
to find that the class Mollusca, whose intimate relationship with the Polyzoa is
universally conceded, abounds with larval forms reducible to the same Peritrichous
formula. A suitable illustration of this fact is afforded by the figures representing the
early larval condition of Chiton anereus, as delineated by Lov^n, and reproduced in
Huxley's ' Manual of the Invertebrata,' and in other zoological textbooks.

Yet another leading section of the Metazoa, that of the Echinodermata, would
appear to admit of being retraced phylogenetically to the group of the Peritricha.
Here, as in the preceding instances, the clue has to be sought among the larval
or embryonic, and not among the adult organisms. The embryo Echinoderm, or so-
called Echinopaedium (Huxley), on leaving the egg, is altogether distinct from the
parent, consisting of a laterally symmetrical, ovate body having usually two, four,
or more girdle-like bands of cilia. Through the process of histolysis or atrophy, this
primary integument with its ciliary girdles becomes speedily obliterated, but there
can be no doubt that during such transient larval existence the young Echinoderm
resembles in a truly remarkable manner such Peritrichous Ciliate Infusoria as Urocen-
trum turbo, PL XXXIII. Figs. 7-9, and Didinium nasutum, PL XXXII. Figs. 50-57,
and woodcut, Fig. 10, the latter type more especially being characterized in its normal

* ' Recherches sur 1'embryologie des Bryozoaires,' 1877.

CLASS II. CILIATA.

condition by the possession of two, and, preceding the act of fission, four, ciliary girdles.
An approximate estimate of this resemblance may be gained by a comparison of the
figures just cited with the accompanying woodcut illustration, Fig. 9, of the earliest
larval or Echinopaedium phase of a Feather-star, Comatula, reproduced from
Haeckel's « Natiirliche Schopfungs-Geschichte.' The Echinus, the Star-fish, or the
Holothurian, one and all, present an identical or but slightly modified initial structure,
and may therefore be consistently regarded as the descendants of a similar simple
Peritrichous archetype.

12

The figures, bracketed in pairs, represent six larval Metazoa, with their respective Infusorial isomorphs, as cor-
related in the accompanying text.

Fig. i, an Astomatous larval Coslenterate or Planula; Fig. 2, an Astomatous Holotrichous Infusorium, Opalina;
_'. 3, a larval Aproctous Turbellarian ; Fig. 4, a Stomatode Holotrichous Infusorium, Paramizciunt ; Fig. 5, a larval
Nemertian, Cephalotkrix, after Macintosh ; Fig. 6, a Cilio-Flagellate Infusorium, Melodinium ; Fig. 7, a Telptro-

chous Annelid larva, after Gegenbaur; Fig. 8, a Peritrichous Infusorium, Telotrochidium ; Fig. 9, a Mesotrochous
Echinoderm larva, after Haeckel ; Fig. 10, a Peritrichous Infusorium, Didinium (prior to subdivision) ; Fig. n, a
typical larval Polyzoon, after Barrois ; Fig. 12, a Peritrichous Infusorium, Vorticella.
The letters or and an indicate respectively the oral and anal apertures.

The small group of the Gephyrea, including notably Sipunculus and Priapulus,
frequently cited as possessing structural modifications that unite the two groups
of the Echinodermata and Annelida, is of interest in connection with the present
subject of discussion since the embryonic zooids, in at least Sipunculus, accord
in their Peritrichous plan of ciliation with those of both the first-named group and
the Polychaetous section of the Annelida. The ciliated embryos of the Polychaetous
Annelida, while thus conforming to the Peritrichous type, are found within such
limits to exhibit three somewhat diverse modifications. As explained by Professor
Huxley in his ' Anatomy of the Invertebrata,' p. 243, the cilia in some cases form
a broad zone which encircles the body, leaving at each end an area which is either
devoid of cilia, or, as is frequently the case, has a tuft of cilia at the cephalic end.
Such larvae are termed " Atrocha." In other embryos the cilia are arranged in one
or more narrow bands which surround the body. Where two bands of cilia are
developed, the one encircling the body immediately in front of the mouth, and the
other around the anal end of the embryo, the larvae are called " Telotrocha." In
the third modification one or many bands of cilia surround the middle of the body
between the mouth and the hinder extremity, such larvae being distinguished by the
title of " Mesotrocha " ; a supplementary tuft of cilia also, in the case of the
Telotrocha, being not unfrequently attached to the centre of the praestomium or pre-
oral region. While such Peritrichous Infusoria as Urocentrum and Didinium conform
more essentially to the Telotrochal larval type, in the intermediate structural form
Calceolus (Peridinium) cypripedium of H. James-Clark, PI. XXXII. Figs. 23 and 24,
having, with the exception of a bare cap-like anterior region, the whole surface of
the body clothed with vibratile cilia, a decided approach is made towards the

478 CLASS II. CILIATA.

Atrochal formula.* It is a further significant fact that in this type a fascicle of long
whip-like cilia is developed from the oral region, which may be regarded as
homologous with the terminal tuft common to both the Atrochal and Mesotrochal
Metazoic larvae. A yet more interesting and significant modification of the Telo-
trochal plan is perhaps exhibited by the recently discovered Peritrichous Infusorium
represented by Fig. 8 of the accompanying woodcut, and upon which, with reference
to the likeness indicated, the author has conferred the generic name of Telotrochidinm,
While somewhat resembling at first sight a temporarily detached Vorticella with a
supplementary posterior ciliary circlet, it differs fundamentally from such a type in
that the anal aperture does not open, as with the typical Vorticellidas, upon the oral
vestibulum, but at the posterior extremity of the body and to the rear of the hinder
circlet of cilia. The anal passage following upon the aperture is conspicuously
visible for some distance within the surface of the cuticulum, and, as will be at once
recognized, it requires but a further prolongation and juncture of the oral and anal
passages to produce an organism indistinguishable from Gegenbaur's representation of
a Telotrochous Annelid larva, reproduced at Fig. 7.

A remaining and very important section of the Metazoa, with which as yet no
attempt has been made to demonstrate an infusorial phylogenetic origin, is that of
the Arthropoda, including most notably the Crustacea, Arachnida, and Insecta. Such
a connection, nevertheless, is, in the author's opinion, obscurely traceable in the
direction of the Hypotricha, the interval separating the first-named highly
differentiated Metazoa from the Protozoic order being bridged over by the group of
the Wheel-animalcules or Rotifera. The passage from the Hypotrichous Ciliata to
the Rotifera is indicated in two completely distinct directions. Firstly, in such a
type as the Dysteria armata of Huxley, PL XLII. Figs. 27 to 30, in which the
complex buccal armature and jointed caudal style are so strongly suggestive of its
Rotiferan affinities that the animal was originally referred by Mr. P. H. Gosse to
the class in question. Secondly, in that aberrant group of the Rotifera, including
Ichthydium, Chatonotus, Turbanella, and a few others, recently incorporated together
by Metschnikoff and Claparede under the title of the Gasterotricha,f which are all
distinguished by the absence of the customarily developed trochal discs and
complex mastax, while the entire ventral surface alone is clothed with fine vibratile
cilia after the manner of the most simple Hypotricha. It is at the same time
necessary to observe that among the generality of the Rotifera, both in their larval
and frequently in their adult state, the cilia form a single terminal wreath around
the so-called trochal disc, and consequently correspond closely with the Telo-
trochous larvae of the Echinoderms and Polychaetous Annelida previously described. J
In common with these larvae, they are likewise apparently phylogenetically derived
from the infusorial order of the Peritricha. In this connection it may be further
remarked that the two endoparasitic Peritrichous genera Ophryoscolex and Ento-
dinium, distinguished by the possession of indurated carapaces and variously
modified spinous appendages, were originally referred to the Rotifera. In one of
these genera it is interesting to find that a second girdle of cilia is developed round
the centre of the body. The affinities of the Rotifera with the Crustacea are, as
indicated by Professor Huxley,§ possibly manifested in " Pedalion, with its jointed
setose appendages and curious likeness to some Nauplius conditions of the lower
Crustacea." It might be further added that many Rotifera, in common with

* The so-called Atrochal larva of the Chaetopodous Annelid Serpula, as originally figured by
Stossich, and reproduced in F. M. Balfour's treatise on Comparative Embryology, vol. i., 1880,
conforms entirely to the Holotrichous plan of ciliation, and with its ventral oral, and postero-
terminal anal apertures, may be directly compared with a Paramachim, or an embryo Turbellarian.

t " Beitrage zur Kenntniss der Entwickelungsgeschichte der Chaetopoden," ' Zeit. Wiss. Zool .'.
Bd. xix , 1869.

\ The resemblance between Rotifers and the larvae of Echinoderms was pointed out by Professor
Huxley in his account of Lacinularia socialis in the ' Transactions ' of the Microscopical Society
for the year 1851, and is further advocated in his ' Anatomy of the Invertebrata, p. 193, 1877.

§ ' Anatomy of Invertebrated Animals,' p. 193, 1877.

CLASS//. CILIATA.

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CLASS II, CILIA TA.

Nauplian Crustaceous lame, are characterized by the possession of only a single
median visual organ. Many of the higher Hypotrichous Ciliata, e. g. Stylonychia
and Euplotes, would finally, by virtue of their not unfrequently branched setose
appendages, appear to exhibit a latent Arthropodous bias.

With the aid of the evidence submitted here and in the preceding volume, it is
finally found possible not only to predicate the probable lines of evolution by which,
out of the Holotrichous, Peritrichous, and Hypotrichous orders of the Infusoria Ciliata,
all of the more important Metazoic groups have been evolved, but also to produce a
genealogic scheme, see p. 479, indicating an unbroken chain of animal organization
of gradually increasing complexity from the lowest Rhizopod up to the Vertebrata.
The broad and seemingly almost insuperable hiatus which, failing the group of the
Spongida, seemed to intervene between the Protozoic and Metazoic series, need no
longer present any substantial obstacle to the taxonomist. For while the three
foregoing orders of the Ciliata still remain undoubted and easily recognized
Protozoa, it as evidently needs but the interposition of some innate force, akin to that
of crystallization, to transform their plastic and comparatively amorphous protoplasmic
bodies into mullicellular aggregates or Metazoa. Nay more, numberless examples
of the Ciliata are multinucleate, and therefore potentially multicellular, and furnish,
by reason of such differentiation, the most perfect possible links of connection
between the Protozoic and Metazoic series. Where, consequently, as in the several
cases here submitted, these Protozoic organisms are more or less perfect isomorphs
of the mature or larval phases of Metazoic structures, it may be consistently
predicated that they are phylogenetically connected with them.

A beautiful and highly instructive illustration of the manner in which a unicellular
and simply nucleated protoplasmic body may pass first into a multinucleate and then
into a multicellular condition is afforded by the figures given by Metschnikoff,*
copied in F. M. Balfour's ' Comparative Embryology,' and herewith reproduced, of
the segmentation of the ovum of the Rose Aphis, Aphis rosce. Fig. 3 in this series is

Figs, i to 4, illustrating four successive phases of the segmentation of the ovum of A $ 'his rusts. A granular central
yolk mass and an outer protoplasmic layer are distinctly visible in every instance. In Figs, i and 2, two and four
nuclei have respectively appeared within the outer protoplasm. In Fig. 3 a number of nuclei have arranged themselves
at regular distances throughout this region, while in Fig. 4 the protoplasmic layer has become divided into a number of
columnar cells, which correspond with the nuclei (after Metschnikoff).

Fig. 5, an adult example of Dicyema iypus, whose histologic composition accords closely with that exhibited by the
aphis ovum represented in the preceding Fig. 4 ; ax, central nucleated axial cell ; ec, multicellular ectodermal layer
(after Ed. Van Beneden).

more especially noteworthy, since it corresponds with a typical Opalina and depicts
that multinucleate and potentially multicellular state that is definitely assumed in
the succeeding phase as delineated at Fig. 4. Metazoa whose adult structure
may be said to be scarcely in advance of what obtains in the simplest multicellular
condition of the ovum delineated at Fig. 4," are found embodied in the two
recently discovered orders of the Dicyemida and Orthonectida. Both of these
consist of mouthless, elongate ovate, more or less completely ciliated, essentially
endoparasitic organisms, the former as yet having been obtained infesting exclusively
the renal organs of various Cephalopoda, while the latter more extensively distributed

* " Embry. Stud. Insecten," 'Zeit. Wiss. Zool.,' Bd. xvi., 1866.

CLASS II. CILIATA. 481

group affects the intestinal viscera and surrounding tissues of various Nemerteans,
Turbellaria, and Ophiurida. In the case of Dicyema, see Fig. 5 of the accom-
panying woodcut, histological differentiation, as attained in the adult, takes the form
of a single peripheral cellular layer, within which is enclosed a single long cylindrical
or subfusiform axial cell. With the Orthonectida, Rhopalura, a slightly more
complex structural formula is introduced through the subdivision of the central
axial cell into cellular elements. The external resemblance that subsists between
Dicyema and certain ciliated Infusoria was held by Claparede and Lachmann to be so
close, that these authorities figured and described one species, D. Muelleri, in their
' Etudes sur les Infusoires,' as a type whose nearest affinities were probably to be
sought for amongst the Opalinidae. As constituting a stage in advance of these
Ciliata, equivalent to that held by Fig. 4 with reference to No. 3 of the segmentation
phases of the aphis ovum here delineated, this interpretation of Dicyema may perhaps
be not inconsistently maintained. It might be further suggested, with reference
to such affinity, that the single axial cell, the sole representative of the hypoblastic
element or entoderm in Dicyema, is to some extent foreshadowed in the remarkably
prolonged and correspondingly axial so-called nucleus, as developed in the more
abnormal Opaline genera Anoplophrya and Hoplitophrya. In recognition of the
essentially intermediate structural position with reference to the Protozoa and
typical Metazoa, that is occupied by the Dicyemida, Ed. Van Beneden* has proposed
to assign it to an altogether distinct and intermediate sub-kingdom, that to be
distinguished by the title of the " Mesozoa." Professor Huxley t is likewise
inclined to support this view, though with reference more to the remarkable
developmental phenomena. In so far as the germs in Dicyema are produced from
within the single axial cell, such reproductive cell is correlated by this authority
with the central " capsule " of a Radiolarian ; while the peculiar manner in which
the peripheral cells in the embryo grow round and partly enclose the axial one,
he maintains, corresponds with the phenomenon of " epiboly " as it occurs in many
ordinary Metazoa.

The embryological evidence so far at disposal, as now submitted and indicated in
the accompanying table, unquestionably points to the derivation of the Ccelenterata,
Turbellaria, Chaetopodous Annelida, and Scolecida from a Holotrichous archetype ;
the embryos in examples of all these Metazoa being completely clothed with fine
vibratile cilia, and scarcely distinguishable from Holotrichous Infusoria. In a second
series, including more especially the Polyzoa, Mollusca, Echinodermata, typical
Rotifera, and many Polychsetous Annelida, the larval forms are characterized almost
exclusively by their Peritrichous plan of ciliation and remarkable conformance with
certain members of the Peritrichous Infusoria ; while in the third Ciliate group, that of
the Hypotricha, there is an apparent modification in the direction of the Rotifera, and
through them to the Arthropoda. Taken collectively, it is clearly shown that the
peritrichously ciliated larval form represents a preponderating factor in the onto-
genetic history of the Metazoic series ; its protozoic isomorphs, as typified by a
Peritrichous Infusorium, being, in accordance with the fundamental laws of evolution,
the archetype or stock-form from whence the principal Metazoic groups were primarily
derived, and out of which, as shown in the accompanying table, the genealogy even
of the Vertebrata may with facility be defined. Though the biogenetic scheme here
introduced is mainly tentative, and necessarily imperfect at many points, it may
be confidently anticipated that a more extended acquaintanceship with the Ciliate
Infusoria and initial or larval phases of the Invertebrata will be productive of data
permitting of a yet closer and more perfect amalgamation of the Protozoic and
Metazoic groups. In many instances, through the epitomization and abbreviation
of their developmental course, the clue sought for is dim or even altogether
obscured, but in other cases it is manifested with an amount of perspicuity that can
scarcely escape the recognition of the earnest interpreter of Nature's problems.

* " Recherches sur les Dicyemides," ' Bull, de 1'Acad. Roy. de Belgique,' torn. xli. No. 6, and
torn. xlii. No. 7, 1876.

t ' Anatomy of Invertebrated Animals,' 1877.

482 ORDER HOLOTRICHA.

Order I. HOLOTRICHA, Stein.

Animalcules free-swimming, more or less completely ciliate throughout ;
cilia alike or differing but slightly in character from one another, sometimes
supplemented by a variously modified extensile or undulating membrane ;
oral and anal orifices usually conspicuously developed ; the cuticular layer
or ectoplasm not unfrequently containing trichocysts.

The order of the Holotricha was originated by Stein for the reception of all
those animalcules in which the surface of the integument is completely clothed with
cilia that agree entirely with or differ but slightly from one another in size and
character. It undoubtedly embodies the most simply organized members of the
class Ciliata, the series as a whole, however, being subject to considerable range
of complexity and offering a tolerably uniform series of gradations from the most
simple types towards the succeeding order of the Heterotricha. In those forms,
more especially such as Lembus, Pleuronema, Panophrys, and Cyclotricha, in which an
extensile or undulating adoral membrane is borne in addition to larger adoral cilia,
the highest differentiation and closest approximation to the Heterotrichous formula
is apparently arrived at It is noteworthy in connection with this circumstance
that the larger adoral fringe of cilia in both the Heterotrichous and Hypotri-
chous orders of the class, as typified by the two genera Stentor and Euplotes, is
represented in its earliest or initial state by a similar membraniform expansion.
Evidence indicative of the comparatively lower organization of the Holotrichous
group of the Ciliata, is afforded by their occasional sporular mode of reproduction.
This, while common to the Flagellata previously described, is as yet unknown among
the higher sections of the Ciliata. Illustrations of such exceptional developmental
phenomena are hereafter recorded in connection more especially with the four
genera Colpoda, Otostoma, Ichthyophthirius, and Amphileptus.

In accordance with Stein's scheme of classification of the Ciliata,* reproduced at
page 210 of vol. i., the order of the Holotricha is, exclusive of the Opalinidae, sub-
divided into the four minor groups or families only of the Trachelina, Enchelina,
Paramsecina, and Cinetrochilina. It has been considered undesirable, however, to
adhere strictly to that scheme in this volume, and this in consequence not only of the
discoveries of numerous Holotrichous types requiring independent family grouping,
that have been made subsequent to the appearance of Stein's work, but on account
also of the evident incongruity in many instances of the generic groups united
under his proposed family headings. Examining these five family groups in
successive order, it will be found that the title of the last one, that of the
Cinetrochilina, has to be entirely abandoned, since Cinetrochilum and its supposed
near ally Glaucoma can no longer be accepted as independent generic types but
as being developmental conditions only of certain Hypotricha. Pleuronema
and Cyclidium, again, differ so remarkably in the character of their membrani-
form appendages from Lembadion, Ophryoglena, and the several other generic
types with which Stein associates them, as to demand independent family dis-
tinction. In Stein's fourth family of the Paramaecina a still more heterogeneous
assemblage of generic forms is encountered, the proposed group including, in addition
to the simply and evenly ciliate Paramada, the diversely ciliated Enchelys, Nassula
with its fish-trap-like pharyngeal armature, the membranous flap-bearing Panophrys,
and various other distinct types. His third family of the Enchelina is composed
of equally inconsistent elements as typified by such entirely dissimilar generic types
as Prorodon — which is immediately allied to Nassula — Coleps, Lacrymaria, Perisfira,
and Actinobolus. The last-named generic form would seem indeed to have no

* 'Infusionsthiere,' Abth. ii., 1867.

GENUS PARAM&CIUM. 483

claim for admission within the ranks of the Holotricha, but to be referable, if any-
where among the Ciliata, to the Peritricha. Stein's second family, of the Trachelina,
is the only one which may be said to embrace generic groups that fairly harmonize
with one another ; even here, however, one out of the five genera named, Loxodes,
is now shown by Wrzesniowski to belong to the Hypotrichous Ciliate group, while
Dileptus cannot be generically separated from Amphileptus. While receiving its
title and definition from Professor Stein, it is worthy of remark that, in common
with the Peritricha, the order of the Holotricha is one of the important groups that
yet awaits systematic description by that eminent authority.

The accompanying table of classification may now be submitted as embodying
what, in accordance with our existing knowledge of the Holotricha, would appear to
constitute the most natural family grouping of the numerous genera, while it at the
same time provides a concise clue to their distinction. In accordance with Stein's
classificatory system, the mouthless Opalinidae are here admitted among the Holo-
tricha, being regarded by the author as either peculiarly modified members of the
order, which by long maintenance of an endoparasitic mode of existence, have become
accustomed to absorb the nutrient juices of their host through the general surface of
their integument, and thus gradually dispensed with the need of a distinct oral
aperture, or which possibly, through having been primarily brought into existence
amid similar surroundings, have failed to develop the requirement of such inceptive
orifice. These alternative interpretations are discussed at length in connection with
the systematic description of this singular organic group.

Fam. I. PARAMJECHD.2E, S. K.

Animalcules free-swimming, more or less flattened and asymmetrical,
ciliate throughout, oral and cuticular cilia alike ; dorsal and ventral surfaces
distinct, the oral aperture opening on the ventral surface.

GENUS I. PARAM^CIUM, Mullen

Animalcules free-swimming, ovate or elongate, asymmetrical, more or
less flexible but persistent in shape, finely ciliate throughout, the cilia of
the oral region not differing in size or character from those of the general
surface of the body ; an oblique groove or buccal fossa developed on the
ventral surface, at the posterior extremity of which the oral aperture is
situated ; cortical layer usually enclosing trichocysts ; contractile vesicle and
endoplast conspicuous, the former under certain conditions sometimes
assuming a stellate outline. Inhabiting fresh and salt water, and abundant
in vegetable infusions.

Paramseeium aurelia, Mull. PL. XXVI. FIGS. 28-30.

Body elongate-clavate or subfusiform, slightly compressed, about four
times as long as broad, narrower and truncate anteriorly, the posterior half
somewhat inflated, terminating in a conical point ; buccal groove prolonged,
extending from the left side of the anterior extremity obliquely backwards
on the ventral surface, towards the right-hand side, beyond the centre of the
body ; oral aperture situated at the posterior termination of the buccal
groove ; anal aperture ventral, situated midway between the oral orifice and
the posterior extremity ; contractile vesicles two in number, stellate when
compressed, situated respectively at a distance of about one-third of the

484

ORDER HOLOTRICHA.

GENUS.
Paramacium.

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486 ORDER HOLOTRICHA.

entire length of the body from the anterior and posterior extremities ;
endoplast ovate, subcentral ; trichocysts numerously developed, forming an
even, vertically disposed, subcuticular layer; natation vigorous, rotatory.
Length of body 1-120" to 1-96".

HAB. — Pond water and in vegetable infusions.

This type, commonly known as the "Slipper Animalcule," is one of the
earliest observed and most widely distributed members of its class. It occurs in
countless numbers in artificial vegetable infusions, as also in its natural condition in
stagnant marsh and pond water. Viewed by transmitted light the dominant colour
is golden-brown, while by direct reflection it presents an almost opaline appearance ;
this circumstance, combined with the elongate contour of the animalcules, won for
them from Joblot and other earlier writers the popular name of " gold and silver
little fishes." The stellate contour of the two contractile vesicles at diastole,
referred to by most authorities as an essential characteristic of this species,
scarcely appears to belong to the natural or persistent state, but would seem to be the
result merely of artificial and abnormal pressure. The examination by the author of
numberless examples with the highest magnifying power, confined in space sufficient
to allow of their free movement, has failed to elicit in connection with these
structures otherwise than a perfectly even, spheroidal outline. Under those artificial
conditions in which the assumption of a stellate contour has been observed, the
contractile vesicles exhibit phenomena agreeing with those recorded later on of
Trachdophyllum apiculatum, Enchdyodon farctus, and other types ; minute, lateral,
pyriform sinuses make their appearance round the periphery of each vesicle at the
time of full diastole and, according to Carter, extend as thread-like canals through the
substance of the parenchyma. With the act of systole, the central spheroidal portion
of the vesicle disappears, leaving the stelliform peripheral sinuses, which now flow
together and form the next central vesicular dilatation. During the process of
transverse fission, as observed by Claparede and Lachmann, two new contractile
vesicles make then: appearance in advance of or anterior to the two old ones, these
latter, on the accomplishment of the act, occupying in each instance the posterior
region of the two newly developed zooids. The phenomenon of so-called longitudinal
fission, PI. XXVI. Fig. 30, accredited to this type by Ehrenberg, is now demon-
strated, as in the succeeding species, to indicate the act of conjugation between two
independent animalcules. The trichocyst layer in Paramcedum aurelia is very
distinctly developed, taking the form of an even series of minute rod-like bodies
disposed vertically immediately beneath the surface of the cuticle. An interesting
account of the earliest record of the existence of these structures, with the descrip-
tion of a simple process by which the animalcule may be induced to extrude them,
as communicated by Sir John Ellis to the ' Philosophical Transactions ' for the
year 1769, will be found at pages 81 and 82 of the preceding volume.

The Paramcedum caudatum of Ehrenberg, distinguished by its more attenuate
posterior extremity, is regarded by Claparede and Lachmann as a mere variety of
this species, if not, indeed, exemplifying its most characteristic form. Paramcedum
aurelia, as figured by these last-named authorities, is represented as possessing a
conspicuous brush-like tuft of longer cilia at the posterior extremity. The author
has recently met with examples having this posterior brush-like tuft, and is inclined
to regard the same as signalizing a well-marked local modification, but certainly
not the predominant type of this cosmopolitan species.

Paramaecium bursaria, Ehr. sp. PL. XXVI., FIGS. 31 AND 32.

Body pouch-shaped, depressed, little more than twice as long as broad;
rounded posteriorly, narrowest and obliquely truncate at the anterior
extremity ; buccal fossa infundibulate, very wide anteriorly, extending
obliquely backwards from left to right to beyond the centre of the body ;

GENUS PARAM&CIUM. 487

oral aperture situated at the posterior extremity of the buccal fossa,
followed by a distinct pharyngeal passage ; anal aperture postero-terminal ;
contractile vesicles two in number, spherical or stellate ; endoplast ovate,
with a laterally attached endoplastule ; trichocysts abundantly developed ;
endoplasmic and cortical layer in adult individuals usually coloured green
through the presence of enclosed chlorophyll-like granules. Length of
body 1-280". HAB. — Marsh water.

This animalcule is referred by Ehrenberg, in his great work ' Die Infusionsthiere,'
to the genus Loxodes ; Focke, in the 'Isis' for the year 1836, being the first to
distinguish it by the generic and specific titles that are here given. A highly
characteristic feature of this species, and one which attracted the notice of the earliest
investigators, is the powerful circulation of the endoplasmic constituents, constantly
and uniformly maintained within the interior of the animalcule's body. Associated
with the usual brilliant green hue of both the moving corpuscles and those of the
more firm and motionless cortical layer or exoplasm, this circulating phenomenon
imparts to the animalcule an aspect highly suggestive of the cyclosis or rotation of
the cell-contents of certain aquatic plants, such as Anacharis and Valisneria. A similar
circulation obtains, but is not so conspicuous, in the young and colourless individuals.
As shown by Stein's figures, and confirmed by the author's investigations, this
rotation of the body-contents exhibits a uniform motion, ascending on the left side
and descending on the right when viewed from a dorsal aspect, and may be thus
described as in conformity with the apparent motion of the sun or the hands of
-a watch when facing the observer.

The reproductive phenomena of Paramacium, as manifested more especially
with the present species, have received a considerable amount of attention at the hands
of recent investigators. Balbiani's name is more especially worthy of notice in this
connection, he having been the first to demonstrate * that the previously so-called
process of multiplication by longitudinal fission of one animalcule was really the
more important act of conjugation or genetic union between two independent
zooids. In the accomplishment of this conjugative act two animalcules apply
themselves closely to one another by their oral or ventral surfaces, the parts thus
brought into immediate contact becoming intimately fused or united with each
other. In this closely united state the two animalcules may remain for a period of
five or six days or more, but ultimately separate and resume their previous inde-
dendent career. As the result of this conjugation the endoplast and endoplastule
undergo an important modification. Originally it was thought by Balbiani that
the last-named of these two structures was interchanged by the two united animal-
cules, and fulfilled the part of a male fecundatory capsule or testis with reference to
the endoplast, which remained stationary and was supposed to enact the role of a
female organ or ovary. As fully related, however, in vol. i. p. 94 et seq., more recent
investigation has not tended to confirm this hypothesis. At the same time it has been
demonstrated by Balbiani and numerous other later authorities that during or subse-
quent to this process of conjugation both the endoplast and endoplastule become
turgid and enlarged, the latter assumes usually a more or less striated aspect, while the
former breaks up into a variable number of spheroidal bodies, which become separated,
and are ultimately cast out of the body, and probably constitute reproductive germs
or ovules. In accordance with an earlier interpretation, it was assumed that the
endoplastule, in its striated condition, represented a bundle of spermatic elements.
The fact, however, that a similar striate aspect is frequently distinctive of this
structure during the more simple process of multiplication by transverse fission, as
also under like conditions of an ordinary cell-nucleus, has rendered this assumption
no longer tenable. The similarly manifested process of conjugation of Paramcecium
aurelia, as delineated by Ehrenberg, is reproduced at PL XXVI. Fig. 30.

' Comptes Rendus,1 1858.

(03 ; *

488 ORDER HOLOTRICHA.

Paramsecium putrinum, C. & L.

This species is described by Claparede and Lachmann as corresponding
in external form with Paramacium bursaria, but as differing from that
animalcule structurally by its non-possession of trichocysts and by the
presence of a single contractile vesicle only, which is situated near the
anterior body-half; the anal aperture is located on the ventral surface,
though not so far forward as in P. aurelia ; endoplast band-shaped, curved,
accompanied by an oval endoplastule.

HAB. — Stagnant water, among decaying vegetable matter.

Paramsecium glaucum, C. & L.

Body ovate or elliptical, rounded at each extremity, the anterior one
slightly the narrower, about twice as long as broad ; cortex enclosing tricho-
cysts ; colour glaucous green ; buccal groove longitudinal, the oral
aperture situated a little in front of the median line ; two posteriorly
situated, stellate, contractile vesicles. Length of body 1-147".

HAB. — Salt water : Norwegian coast (Claparede and Lachmann).

Paramsecium marina, S. K. PL. XXXII. FIG. 9.

Body elongate-ovate, subclavate, about five times as long as broad,
rounded and widest posteriorly, tapering and slightly curved in the anterior
region ; oral groove extending backwards to the centre of the body ; con-
tractile vesicle single, of large size, posteriorly situated ; endoplast ovate,
subcentral. Length 1-240". HAB. — Salt water.

This species was obtained in some abundance in the small rock pools refilled
only by the spring tides, at both Teignmouth and Anstey's Cove, South Devon, in
July 1879. The motion of the animalcules in these pools, as observed with the aid
of a pocket lens, was highly characteristic, consisting of progress backwards and
forwards for long distances, and in the same straight line, accompanied by rotation
on their longitudinal axes, after the manner of various Bacteria and Vibriones.

Supplementary Species.

The Paramadum inversum and P. ovale of Claparede and Lachmann are referable
to the genus Trichoda of Stein, while the Paramcecium microstomum of the same
authorities would appear to belong to the genus Isotricha. The Paramacium chry-
salis of Ehrenberg is now referred ^o the genus Pleuronema, and his Paramacium
colpoda to Colpidium.

GENUS II. LOXOCEPHALUS, Eberhard.

Animalcules free-swimming, persistent in shape, elongate-ovate or sub-
cylindrical, having an oblique constriction at a little distance from the
anterior extremity, and bearing in this region, on one or both sides, one or
more short, curved setae ; the anterior extremity somewhat obliquely truncate,
and bent slightly to one side ; one or more long, hair-like caudal setae
developed at the posterior extremity ; cilia of the cuticular surface fine, even
throughout ; endoplasm more or less granular and opaque ; oral aperture
ventral, subterminal, indistinct.

GENUS PL AC US. 489

Loxocephalus luridus, Eberhard. PL. XXXII. FIG. 16.

Body elongate-ovate, subcylindrical, three times as long as broad,
widest centrally, tapering gradually towards the two extremities ; the
oblique anterior constriction bearing on the side nearest the apical ex-
tremity two short, conspicuous, adcurved setae ; four long, straight, hair-like
caudal setae developed from the posterior termination ; endoplast sub-
spherical, situated in the median line at a distance of one-third of the entire
length from the anterior extremity ; endoplasm granular, very dark and
opaque. Length 1-75". HAB. — Infusions with vegetable matter.

This species is figured and described by Dr. Ernst Eberhard in the 'Oster-
Programm der Herzogl. Realschule zu Coburg' for the year 1862.

Loxocephalus granulosus, S. K. PL. XXVI. FIG. 47.

Body elongate-ovate or subreniform, two and a half times as long as
broad, widest posteriorly, the anterior end curved slightly towards the left,
the oblique anterior constriction bearing on each side, as viewed from a
dorsal aspect, a single, short, adcurved seta; a single, straight, hair-like
caudal seta projecting from the posterior termination ; contractile vesicle
situated in the median line at a distance of one-third of the length of the body
from the posterior extremity ; cilia short and fine throughout ; parenchyma
coarsely granular, dark and opaque. Length 1-428".

HAB. — Marsh water with decaying vegetation.

The animalcule connected with the above title was obtained by the author in
some abundance in marsh water from Le Marais, Jersey, November 1878, in com-
pany with Spirostomum ambigiium, Paramcecittm aurelia, Uroccntrum turbo, Pkuronema
chrysalis, and other pond-frequenting types. The general contour, as^een with
moderate magnification only, agrees so closely with that of Colpidium or Pleurochili-
dium, that at first sight the desirability of referring it to one of these two genera was
anticipated. On closer examination, however, it was found to be entirely wanting
in the special oral structure that distinguishes these latter. No trace of an undu-
lating membrane or of a pharyngeal passage could be detected, while even with a
magnification of eight hundred diameters the position of the oral aperture in the
antero-ventral region could be predicated only by the more active ciliary vibration at
that point. The two short adcurved setae projecting from the anterior constriction,
accompanied by the presence of a long hair-like posterior seta, demonstrate that we
have here an animalcule closely allied to the Loxocephalus luridus of Eberhard, but
from which, as a species, it may be at once distinguished by its considerably smaller
size, and by the diverse number and disposition of the setose appendages. When
disturbed the animalcules swim to and fro in a straight line with considerable
rapidity, but otherwise remain quiescent in some selected spot, numerous examples
being often found in close proximity. In consequence of the dense granular
character of the endoplasm, some difficulty was experienced in ascertaining the
position of the contractile vesicle and endoplast.

GENUS III. PLACUS, Cohn.

Animalcules free-swimming, ovate ; cuticular surface indurated, reticu-
late ; oral aperture inferiorly situated ; fine, short, vibratile cilia distributed
throughout the cuticular surface, none of a specialized charactef in the
neighbourhood of the mouth ; endoplast and contractile vesicle conspicuous,

VOL. II. C

490 ORDER HOLOTRICHA.

Placus striatus, Cohn. PL. XXVI. FIGS. 39 AND 40.

Body ovate, slightly flattened, about twice as long as broad, the two
extremities rounded ; oral aperture circular, situated on the ventral surface
at a short distance from the anterior extremity ; cuticular surface furrowed
obliquely in opposite directions, and so producing a reticulate aspect.
Endoplast spherical, central ; contractile vesicle posteriorly situated. Move-
ments swift, in a straight line, rolling or rotatory on its long axis. Length
1-780". HAB. — Salt water, among Conferva.

Excepting for the absence of the vibratory oral membrane, Cohn* regards this
form as most nearly resembling Glaucoma ; the indurated and reticulate cuticle at
the same time corresponds to some extent with that of Coleps.

GENUS IV. CONCHOPHTHIRUS, Stein.

Animalcules free-swimming, persistent in shape, ovate or suborbicular,
with a convex dorsal and flattened ventral surface ; oral aperture situated
within a more or less funnel-shaped fossa or depression on the ventral
surface, followed by a tubular, recurved pharynx ; cuticular surface indurated,
delicately striate and ciliate throughout ; cilia fine, thickly set, usually
presenting a tufted or matted aspect ; endoplast and contractile vesicle
conspicuous. Occurring within the body-mucilage of various Lamelli-
branchiate and Gasteropodous Mollusca.

Conchophthirus anodontae, Ehr. sp. PL. XXVI. FIG. 33.

Body elongate-oval, depressed, about twice as long as broad, bluntly
rounded at the two extremities ; oral fossa spacious, occupying the centre
of the ventral surface, the pharyngeal tract recurved, extending to within
a short distance of the posterior extremity ; contractile vesicle simply
spherical, subcentral ; endoplast globular, posteriorly located. Length of
body 1-200".

HAB. — The body mucilage of Anodontidae and other fresh-water
Mollusca.

This animalcule, selected by Stein as the type of the genus Conchophthirus, is
identical with the Leucophrys anodontce of Ehrenberg, and apparently also the
Plagiotoma acuminata of Claparede and Lachmann. The illustration here given of
this species is reproduced from T. W. Engelmann's "Zur Naturgeschichte der
Infusionsthiere," contained in the ' Zeitschrift fur Wissenschaftliche Zoologie ' for the
year 1861, where it is figured by way of comparison with Conchophthirus cttrtus,
described later on.

Conchophthirus Steenstrupii, Stein. PL. XXVI. FIGS. 34 AND 35.

Body broadly oval, depressed, equally rounded at the two extremities,
about one and a half times as long as broad ; oral fossa widely infundibular,
somewhat rectilinear, occupying the first third or quarter of the right-hand

* " Neue Infusorien im Seeaquarium," ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xvi.,
1866.

GENUS PRORODON. 491

lateral border of the ventral surface ; cuticular surface delicately striate
longitudinally, cilia closely set, long, fine, and matted ; the anterior ex-
tremity apparently bearing a small fascicle of longer setose cilia ; contrac-
tile vesicle spherical, subcentral, exhibiting at diastole minute, supple-
mentary peripheral lacunae ; endoplast consisting of as many as seven
nucleus-like corpuscles, disposed in a row parallel with the posterior and
right-lateral border. Length 186" to 1-270".

HAB. — Body-slime of Succinea amphibia, and also that of many land
snails, including Helix hortensis.

The more anterior location of the oral fossa, together with the animalcule's
separate habitat, serves to distinguish this form from the two accompanying repre-
sentatives of the genus.

Conchophthirus curtus, Eng.

Body shortly oval, nearly as broad as long, equally rounded at both
extremities, the dorsal surface highly convex, the ventral one flattened ;
oral fossa subcentral, very small, continued into a long, recurved, tubular
pharynx ; cuticular surface delicately striate longitudinally, clothed through-
out with long, fine, matted cilia ; endoplast oval, subcentral, contractile
vesicle located a little behind this structure, stelliform or rosette-shaped at
the time of diastole. Length 1-200."

HAB. — Mucilage of the fresh-water mussel Unio crassus, in company
with C. anodontce.

Although found in company with Conchophthirus anodonta, Engelmann considers
that the shorter or more orbicular, contour of the body, together with the smaller
comparative size of the oral fossa, distinguishes it sufficiently for separate specific
recognition ; the character of the contractile vesicle affords another point of
differentiation.

Fam. II. PRORODONTID-ffi, S.K.

Animalcules free-swimming, symmetrically ovate or cylindrical, entirely
ciliate ; oral and cuticular cilia alike in size and character ; oral aperture
terminal or lateral ; pharynx distinct, usually plicate or armed with rod-like
teeth.

This family group coincides most nearly with the Decteria of Max Perty (vol. i.
p. 204), which is restricted exclusively, however, to those genera in which the
pharynx is armed with rod-like teeth. By Stein, the very closely allied genera Proro-
don and Nassula are, as shown in his classificatory system, reproduced at page 210
of vol. i., distributed among his two very heterogeneous families of the Enchelina
and Paramaecina.

GENUS I. PRORODON, Ehrenberg.

Animalcules persistent in shape, symmetrically ovate, cylindrical or
slightly compressed, rounded at the extremities, entirely and evenly ciliate
throughout; the oral orifice situated at or closely adjacent to the anterior pole,
and the anal aperture at the opposite or posterior one; pharynx strengthened
by a special induration consisting usually of rod-like teeth, but sometimes

C 2

49 2 ORDER HOLOTRICHA.

taking the form of a simple corneous tube; contractile vesicle mostly single,
located close to the anal aperture ; cortical layer sometimes enclosing
trichocysts.

The apical position of the oral aperture alone distinguishes the representatives
of this genus from those of Nassula. Most of the species frequent pond and
stagnant water. Their motion in the water is rapid, and chiefly rotatory on the
longitudinal axis. One form only is as yet recorded as having a marine habitat.

Prorodon niveus, Ehr. PL. XXVI. FIGS. 36 AND 49.

Body elliptical, compressed, about twice as long as broad, oral aperture
terminal ; pharyngeal armature consisting of a short, compressed fascicle
of numerous closely approximated rod-like teeth ; endoplast band-like,
curved, often S-shaped ; contractile vesicle single, spherical, postero-terminal ;
no trichocysts ; colour white. Length of body 1-72".

HAB. — Bog water, amongst Conferva.

The large size of this animalcule, and the high development of the pharyngeal
armature, readily distinguish it from the other members of the genus. Seventy
and eighty-three of the characteristic rod-like teeth are reported by Ehrenberg as
being respectively present in the one half only of the rod-fascicles exposed to view in
two examples that were made the subject of careful examination.

Prorodon teres, Ehr.

Body ovate, cylindrical, twice as long as broad, slightly narrowed
anteriorly ; oral aperture exactly terminal ; pharynx enclosing an elongate
cylindrical fascicle of rod-like teeth ; endoplast ovate ; contractile vesicle
single, postero-terminal; no trichocysts. Length of body 1-140".

HAB. — Pond water.

The cylindrical fascicle with which the pharyngeal cavity of this species is
strengthened has been estimated to contain from twenty to as many as forty -five of
the characteristic rod-like teeth. Encystment, accompanied by the partition of
the animalcule into two equal halves within its cyst, has been reported by Cohn.*

Prorodon griseus, C. & L.

Body ovate, cylindrical, rounded at the two extremities, slightly the
widest anteriorly, from two to two and a half times as long as broad ;
cuticular surface finely and closely striate longitudinally; oral aperture
subterminal ; pharyngeal rod-fascicle large, cylindrical, slightly curved ;
endoplast oval, enclosing a small endoplastule ; contractile vesicle single,
postero-terminal, of large size ; colour clear brown when viewed as a
transparent object, white by reflected light ; no trichocysts. Length of
body 1-250". HAB. — Stagnant water : Berlin (Claparede and Lachmann).

Prorodon armatus, C. & L.

Body nearly globular, slightly compressed, oral aperture subterminal ;
pharyngeal rod-fascicle cylindrical, wide, and comparatively short ; endoplast

* 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. iii., 1853.

GENUS PRORODON. 493

elliptical, of small dimensions ; contractile vesicle single, postero-terminal,
communicating at the time of systole with three or four spherical lateral
sinuses ; numerous trichocysts enclosed in the cortex of the anterior half of
the body, none in the posterior one. Length 1-250". HAB. — Pond water.

Prorodon edentatus, C. & L. PL. XXVI. FIG. 43.

Body elongate-ellipsoidal, cylindrical, nearly three times as long as
broad, transparent, surface of cuticle longitudinally striate, striae separated
considerably from one another ; oral aperture terminal, slightly eccentric ;
pharyngeal armature consisting of a simple, conical, corneous tube developed
backwards to the centre of the body and gradually diminishing in size as it
approaches the posterior end ; endoplast oval, elongate ; contractile vesicle
single, spherical, postero-terminal ; no trichocysts ; cilia of the posterior
extremity longer than those of the general surface, produced in a tuft-
like manner. Length of body 1-250". HAB. — Pond water.

Prorodon marimis, C. & L.

Body elongate, cylindrical, from two to two and a half times as long as
broad, the cuticular surface not longitudinally striate ; oral aperture exactly
terminal ; pharyngeal tube simple, edentulate, very small and short ; con-
tractile vesicle postero-terminal; endoplast ovate; colour transparent,
enclosing numerous dark, refringent granules. Length of body 1-250".

HAB. — Salt water : Norwegian coast (C. & L.).

Prorodon margaritifer, C. & L. PL. XXVI. FIG. 44.
Body elongate-elliptical, subcylindrical, three times as long as broad,
slightly widest anteriorly ; cuticular surface finely and closely striate longi-
tudinally ; oral aperture subterminal ; pharyngeal tube large, consisting of
numerous, short, rod-like teeth ; contractile vesicles very numerous, com-
paratively small and spherical, distributed throughout the substance of the
cortical layer ; no trichocysts ; endoplast double, consisting of two obliquely
converging elliptical bodies, separated from one another at the nearest point
of convergence by a smaller spherical body which apparently represents
the nucleolus or endoplastule ; colour of the general substance of the body
clear brown, contents of the contractile vesicles pinkish. Length 1-75."
Habitat unrecorded.

In the number of its contractile vesicles this species stands almost alone
among those representatives of the class Infusoria with which we are as yet
familiar. The figure here reproduced from Claparede and Lachmann's treatise,*
shows over forty of these vesicles on that side only of the animalcule which is
exposed to view, so that very few short of one hundred may be accepted as
the total number of these structures contained within the cortical layer of a
single zooid. These vesicles do not appear to have any communication with
one another, but expand and contract independently. A closely similar but less
numerical development of the contractile-vesicular system has recently been
found by the author to obtain in Trachclius ovum. Claparede and Lachmann

* ' Etudes sur les Infusoires,' 1858.

494 ORDER HOLOTRICHA.

have remarked of the singular-shaped endoplast of this species that it is not, as in
most instances, imbedded within the cortical layer, but lies loosely in the semifluid
internal endoplasm, permitting the body to revolve freely over and around it. This
phenomenon of the revolution of the body over the endoplast has been reported
by Siebold in connection with other infusorial types, but has been explained by
Eckhard as being a mere optical illusion. Claparede and Lachmann are, however,
so thoroughly convinced of the free suspension of the endoplast in this instance,
that they are disposed to accept Siebold's statement as correct. It is a matter of
regret that the discoverers of this species have omitted to place on record both the
dimensions and habitat of this highly interesting type. Judging from the size of
three species of the same genus, Prorodon marinus, P. armatus, and P. griseus,
delineated in their treatise, it would appear to considerably exceed these in size
and to most nearly approach P. niveus.

Doubtful Species.

The Habrodon curvatus of Max Perty, ' Kleinster Lebensformen,' 1852, charac-
terized as follows, would appear to be rightly referable to the genus Prorodon :
" Body subcylindrical, slightly curved, thickened posteriorly, mostly truncate in front ;
oral aperture anterior, associated with a very delicate dental apparatus ; anal aperture
postero-terminal ; cilia disposed in longitudinal rows, colour grey or pale green ;
movements slow. Length 1-390" to 1-132". Hab. — Spring water, with Chara,
Bern."

GENUS II. NASSULA, Ehrenberg.

Animalcules ovate, cylindrical, flexible but not polymorphic, usually
highly coloured ; oral aperture lateral ; pharynx armed with a simple horny
tube, or with a cylindrical fascicle of rod-like teeth ; entire surface of cuticle
finely and evenly ciliate ; the cortical layer sometimes containing tricho-
cysts ; contractile vesicle single or multiple. Inhabiting fresh water.

A prominent characteristic of the genus Nassula is the normally bright colouring
of the parenchyma or body-contents — rose-colour, red, green, blue, yellow, and
violet being separately developed or variously combined in the several species.
In that form, N. ornata, with which the colour violet is more usually dominant,
this pigment occurs distributed in scattered vesicular patches, which are most
abundant in the anterior region. Ehrenberg was led to regard these coloured
vesiculae as glands possessing probably a biliary function. By Stein, however,
both the generally dispersed and vesicular aggregations of colouring matter are
pronounced to be merely the product of incepted food-material; certain Oscilla-
toriae devoured by one variety, N. ambigua, having been observed by him to pass
successively through the tints of green, blue, and red during the process of digestion.
Claparede and Lachmann, while endorsing Stein's views so far as relates to the
coloured material within the semifluid endoplasm, and which is in a constant state
of circulation, are inclined to attribute to the stationary pigment-corpuscles imbedded
within the cortical layer the character of organs whose special function is not as
yet determined. Stein has recently proposed to separate Nassula ornata, JV. rubens,
and all other members of this generic group in which trichocysts are abundantly
developed, under the distinct title of Acidophorus. Such importance is not, how-
ever, here conceded to the presence of these structures, their development being
subject to considerable variations even among individuals of the same species. The
distinct lateral location of the oral aperture serves to readily distinguish this genus
from Prorodon.

Nassula ornata, Ehr. PL. XXVI. FIG. 42.

Body ovate, cylindrical, two or three times as long as broad, brownish-
green, variegated with violet vesicles ; pharyngeal rod-fascicle forming an

GENUS NASSULA. 495

even, straight, undilated tube; contractile vesicle single, spherical, sub-
central ; numerous vesicular spaces, with violet-coloured contents, usually
present in the anterior region ; no trichocysts. Length of body 1-96".
HAB. — Pond water.

The Nassula elegans and N. conica of Ehrenberg appear to differ from this species
merely in the subordinate character of colour, the former variety being white or
greenish and the .latter yellow or brown.

Nassula flava, C. & L.

Body elongate, cylindrical, three or four times as long as broad, slightly
depressed in the antero-dorsal region ; colour mostly yellow or brick-red ;
pharyngeal armature consisting of numerous rod-like teeth, the tube they
form being much dilated at the distal end ; anterior extremity of the
cortical layer usually containing numerous violet-coloured corpuscles, which
do not circulate with the general contents ; contractile vesicles two in
number, simply spherical. Length of body 1-240" to 1-125".

HAB. — Pond water, among Oscillatoria.

This species, while differing from N. ornata Ehr., as explained by Claparede and
Lachmann, in the form of the pharyngeal tube and the possession of two contractile
vesicles, approaches it so closely in all other details as to render it doubtful
whether it must not be regarded as a mere local variety of that type.

Nassula ambigua, Stein. PL. XXVI. FIG. 41.

Body shortly oval or elliptical, cylindrical, equally rounded at both
extremities, not quite twice as long as broad ; pharyngeal armature con-
sisting of a simple horny tube dilated at its anterior extremity ; contractile
vesicle single, spherical or assuming a stellate outline, medianly located.
Length of body 1-240". HAB. — Pond water.

A species, apparently identical with this form, recently obtained by the author
from ditch water at St. Heliers, Jersey, exhibited numerous trichocysts in the
substance of its cortical layer, and was coloured deep green, more especially in the
posterior region, through the inception of food-particles. While the first example
observed showed apparently a simply tubular pharynx, other specimens, examined
with a higher magnification, revealed the presence of the rod-like teeth characteristic
of the two preceding forms.

Nassula rubens, C. & L.

Body elongate, cylindrical, three times as long as broad, equally rounded
at the two extremities, brick-red or rose colour ; pharyngeal armature con-
sisting of separate rod-like teeth, the tube formed by them being slightly
dilated anteriorly ; trichocysts large and abundant ; contractile vesicle
single, spherical, subcentral. Length 1-500". HAB. — Pond water.

This species is identified by Claparede and Lachmann with the Cyclogramma
rubens of Perty. The genus Cyclogramma, as instituted by the last-named author,
was distinguished from Nassula by the presence of concentric striae in or upon the
cuticular substance. These apparent striae are now shown to represent the im-
perfect optical aspect of the closely approximated trichocysts, as seen with an
insufficient defining power, that occur so abundantly in this and other species of the

496 ORDER HOLOTRICHA.

genus. While most usually of a brick-red hue, Claparede and Lachmann mention
that the colour in this species is sometimes entirely absent, while in other instances,
through the presence of enclosed Oscillatoriae, it assumes a brilliant glaucous hue.

Nassula lateritia, C. & L.

Body ovoid, cylindrical, twice as long as broad, rounded posteriorly, the
anterior border obliquely truncate ; pale red or rose colour ; mouth opening
on the truncate anterior portion; pharyngeal armature consisting of an
anteriorly dilated tubular fascicle of rod-like teeth ; contractile vesicles two
in number, spherical ; endoplast discoidal, posteriorly situated ; trichocysts
numerous, relatively smaller than in N. rtibens. Length 1-500".

HAB. — Pond water.

Nassula microstoma, Cohn.

Body persistent in shape, oblong, slightly compressed, the anterior
extremity bluntly rounded, the posterior one somewhat pointed ; a depressed
area, which conducts to the circular oral aperture, developed on one side,
near the anterior extremity ; pharyngeal tube obliquely directed, simple and
unarmed, dilated posteriorly ; endoplast subcentral, obliquely placed, having
an attached endoplastule ; contractile vesicle small, spherical, located at a
distance of one-third of the entire length of the body from the posterior
extremity ; surface of cuticle finely striate or furrowed longitudinally ; cilia
fine, set in these furrows, equally clothing the entire cuticular surface ; colour
flesh-red. Length 1-240". HAB. — Salt water.

Cohn * remarks that this type most nearly resembles the Prorodon marimis of
Claparede and Lachmann, and may possibly be identical with O. F. Miiller's Para-
mcerium chrysalis, or the Panophrys chrysalis or rubra of Dujardin.

Doubtful Species.

The Liosiphon Stromphii of Ehrenberg, separated from Nassula on account of
the great projection of the anterior region beyond the oral aperture, scarcely
appears to possess a sound claim for separate generic distinction. Its form is
obtusely ovate, colour green, length 1-432", hab. pond water ; the tubular pharyngeal
passage encloses a cylindrical or somewhat clavate fascicle of rod-like teeth, as
obtains among the majority of the members of the present genus.

GENUS III. CYRTOSTOMUM, Stein.

Animalcules ovoid or elliptical, highly contractile ; oral aperture lateral,
taking the form of a longitudinal cleft ; pharynx tubular, its wider anterior
extremity armed with two closely approximated rows of short, rod-like
teeth ; cilia of cuticular surface disposed in even longitudinal rows ; tricho-
cysts usually present. Inhabiting fresh water. ,

This genus, as founded by Stein on the Bnrsaria (Frontonia) leucas of Ehrenberg,
differs chiefly from Nassula in the highly elastic consistence of the cuticular invest-
ment, which allows the animalcules to assume a variety of polymorphic contours.

* " Neue Infusorien im Seeaquarium," ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xvi.
1866.

GENUS ISOTRICHA. 497

The oral apparatus, though described as consisting of two closely approximated
rows of rod-like teeth, is, as distinctly indicated in Ehrenberg's original drawings, a
mere ovate-shaped modification only of the subcylindrical rod-fascicle distinctive of
the genera Nassula and Prorodon.

Cyrtostomum leucas, Ehr. sp. PL. XXVI. FIG. 37.

Body ovoid or ellipsoidal, usually wider anteriorly, about twice as long
as broad ; cortical layer enclosing numerous trichocysts ; oral aperture
elongate-ovate, its lower extremity pointed. Length of body 1-144".

HAB. — Fresh water.

This species, accepted by Stein as the representative of the new genus Cyrto-
stomutn, is identified by that authority with both the Bursaria leucas and Bursaria
vernalis of Ehrenberg (Panophrys do. do. Dujardin), the latter form, as also attested
to by Claparede and Lachmann, being a mere variety coloured green through
the ingestion of chlorophyllaceous food-substances. An account of the minute
histology and behaviour of the trichocysts so abundantly developed in this species,
as carefully worked out and described by Professor Allman, is contained in the
section treating of these structures generally in pages 80-84 of the preceding
volume, while a reproduction of that authority's figures of these elements is
included in the supplementary plate at the end of the atlas devoted to the delinea-
tion of histological details.

.
. GENUS IV. ISOTRICHA, Stein.

Animalcules free-swimming, obovate, persistent in shape, depressed or
subcylindrical; oral aperture ventral, subterminal, followed by a short,
smooth, tubular, membranous pharyngeal passage ; anal aperture postero-
terminal ; cuticular surface clothed throughout with long, fine, densely
disposed cilia. Occurring mostly as endoparasites within the first stomach
or rumen of various higher Ruminantia.

In general contour and habits, and in their long, dense ciliary clothing, the
animalcules of this genus are reported as closely resembling the Opalinidse;
the presence of a well-defined oral aperture serves, however, at once to distinguish
them from the members of the last-named group.

Isotricha intestinalis, Stein.

Body obovate, slightly flattened, longitudinally striate ; oral aperture
ventral, situated within a semilunar depression at some little distance from
the anterior border ; cilia long and fine ; contractile vesicles numerous,
distributed chiefly in the anterior region ; endoplast elongate oval, asso-
ciated with a small, subglobose endoplastule. Dimensions unrecorded.

HAB. — Endoparasitic, within the first stomach or rumen of sheep and
cattle.

Isotricha prostoma, Stein.

Having the oral aperture at the anterior extremity, nearly in the axial
line. All other details, including habitat, corresponding with thoss.
/. intestinalis.

w/* • • >\

UJ LIBRARY

498 , ORDER HOLOTRICHA.

Isotricha (P) microstomum, C. & L. sp. PL. XXVI. FIG. 38.

Body subcylindrical, equally rounded at both extremities, slightly con-
stricted centrally ; about two and a half times as long as broad ; cuticular
surface finely striate longitudinally, entirely clothed with long, fine, even
cilia ; oral aperture minute, situated at a distance of one-third of the
length of the entire body from the anterior extremity, followed by a short,
tubular, backwards-directed pharyngeal tract ; contractile vesicle single,
spherical, located a little behind the centre of the right-hand border.
Length 1-250". HAB. — Salt water: Norwegian coast (C. & L.).

This species is referred by Claparede and Lachmann to the genus Paramacium,
from all the typical examples of which it, however, differs in its symmetrical
contour and in its simple tubular oral aperture, unassociated with any adoral
groove. This combination of characters accords so closely with those of Stein's
genus Isotricha that it becomes requisite either to refer it to that group, or, in virtue
of its non-endoparasitic habits, to establish a new genus for its reception. While
the former alternative commends itself most favourably for adoption, it must at
the same time be observed that the induration of the short tubular oesophagus is
alone wanted to convert this type into a normal member of the genus Nassula, and
it is just possible that such a structure has been overlooked by its observers.
Among the examples of this animalcule examined by Claparede and Lachmann
several were distinguished by their yellow-brown tint.

GENUS V. HOLOPHRYA, Ehrenberg.

Animalcules free-swimming, ovate or globose, elastic and changeable in
form, entirely ciliate ; the mouth situated at the anterior pole, and the anal
aperture at the opposite or posterior extremity ; pharynx simple, having no
corneous tube or rod-fascicle; no specially large cilia developed round
the oral aperture ; multiplying by transverse fission, and forming spherical
encystments. Chiefly inhabiting fresh water.

The members of this genus somewhat resemble those of Prorodon, the most
essential features of distinction being the unarmed character of the pharyngeal
passage and elasticity of the cuticle, which permits the animalcules, as in Cyrto-
stomum, to assume a great variety of outline.

Holophrya ovum, Ehr. PL. XXVI. FIG. 45.

Body ovate, more or less -cylindrical, about one and a half times as long
as broad ; surface of cuticle obliquely striate or corrugate ; cilia short, fine,
and closely set ; colour green or transparent ; oral aperture apical, its border
slightly projecting ; contractile vesicle single, spherical, situated posteriorly,
close to the anal aperture ; endoplast rounded or ovate, subcentral. Length
1-2 10". HAB. — Pond water, amongst Conferva.

Although an ovate outline represents the typical contour of this species, it
frequently assumes an inflated, subspheroidal shape, the characteristic cuticular
striae becoming entirely obliterated ; it is often impossible, under these conditions,
even to recognize the position of the mouth, the animalcule having the aspect of
a complete sphere, which may be either perfectly transparent or more or less
coloured with chlorophyll-granules, or opaque through the ingestion of food-particles.

GENUS HOLOPHRYA. 499

Holophrya discolor, Ehr.

Body ovate, pointed posteriorly, about twice as long as broad ; cilia
long, disposed in widely separated longitudinal rows ; parenchyma green or
colourless. Length 1-240". HAB. — Pond water.

Holophrya tarda, Quenn. PL. XXVI. FIGS. 59 AND 60.

Body when extended nearly three times as long as broad, elongate-
pyriform, somewhat flask-shaped, rounded posteriorly, tapering gradually
towards the narrower and truncate anterior extremity; cuticular surface
finely ciliate, striate longitudinally ; body in contraction subspherical,
with the longitudinal striations obliquely set ; contractile vesicle postero-
terminal ; endoplast elongate-ovate, stationed a little in front of the con-
tractile vesicle. Length 1-300". HAB. — Salt water.

This as yet single known salt-water species of the genus Holophrya is figured
and described by August Quennerstedt in his " Bidrag til Sveriges Infusoriefauna,"
contributed to the 'Acta Universitatis Lundensis' for the year 1865. So far
as its external contour and the relative form and position of the endoplast and
contractile vesicle are concerned, it would appear to be most nearly related to the
Holophrya Kessleri of Mereschkowsky next described.

Holophrya Kessleri, Mereschk.

Body contractile and variable in form, elongate-ovate, subcylindrical,
sometimes slightly wider anteriorly, about twice as long as broad ; cuticular
surface alternately grooved and ribbed longitudinally, finely ciliate through-
out ; parenchyma transparent or with a yellowish tinge ; contractile vesicle
large, posteriorly situated ; endoplast band-like, subcentral. Length 1-170"
to 1-130".

HAB. — Fresh water : Lake Onega (Mereschkowsky), among aquatic
vegetation.

This species is distinguished, according to Mereschkowsky,* by the ribbed char-
acter of the cuticular surface and the band-like contour of the endoplast, both of
which characters are nevertheless shared by the salt-water Holophrya tarda of A.
Quennerstedt. When viewed end-on, these longitudinal ribs are found to range from
twenty-five to thirty in number, the animalcule under such circumstances presenting
an almost melon-like appearance. It does not appear that these ribs become
obliquely twisted when the animalcule is contracted, as obtains in H. tarda.

Holophrya brunnea, Duj.

Body elongate-cylindrical, equally rounded at the two extremities, two
and a half times as long as broad ; colour brown. Length of body 1-125".
HAB. — Pond water.

This form, in common with Holophrya ovum and H. discolor, assumes after
feeding a subglobose or perfectly spherical contour.

* " Studien iiber Protozoen des nordlichen Russland," ' Zeitschrift fur Wissenschaftliche
Zoologie,' Bd. xvi., 1878.

500 ORDER HOLOTRICHA.

Supplementary Species.

The Holophrya coleps of Ehrenberg, thus characterized : — " Body oblong, cylindri-
cal, rounded at both extremities ; colour whitish. Length 1-430" to 1-280" "
is identified by Stein with the Coleps inermis of Perty, and elevated by him to the
rank of a new genus, distinguished by the name of Plagiopogon.

Holophrya lateralis, S. K. PL. XXVI. FIG. 46.

Body cylindrical, evenly ovate or elliptical, a little over twice as long as
broad ; cuticular cilia conspicuous, arranged in numerous closely approxi-
mated, even, longitudinal rows ; contractile vesicle lateral, situated a little
in advance of the median line ; endoplast inconspicuous ; endoplasm
enclosing innumerable, minute, spherical corpuscles, in addition to the
ordinary digestive vacuoles. Length i-ioo".

HAS.— Fresh water : Bombay (H. J. C.).

An animalcule answering to the above diagnosis, and possessing the charac-
teristic terminal oral and anal apertures of the genus Holophrya, is figured and
briefly described, without name, in the manuscript notes kindly placed at the author's
disposal by Mr. H. J. Carter. The species differs essentially from all previously
described members of the genus in the lateral instead of terminal location of the
contractile vesicle. The flexibility of the integument of this type was demonstrated
by the flattened or contorted shapes it assumed in passing and pressing against
confervoid filaments or other objects in the water.

GENUS VI. OTOSTOMA, Carter.

Animalcules free-swimming, ovate, subcylindrical, entirely ciliate ; oral
aperture inferior, subterminal, conducting to a short, recurved, indurated
pharynx, the contour of which, in profile, resembles that of a human ear ;
anal aperture, endoplast, and contractile vesicles conspicuous.

Excepting for the peculiar conformation of the pharyngeal tube, the single type
of this genus corresponds essentially with the genus Nassula ; a still more marked
divergence in the same direction is noticeable in Cohn's new generic type, Hdico-
stoma, next described.

Otostoma Carter!, S. K. PL. XXVI. FIGS. 55-58.

Body ovate, rounded at each extremity, not. quite twice as long as
broad, slightly narrower anteriorly ; oral aperture situated in a depression
on the ventral surface, at a distance of about one-third of the length of the
entire body from the anterior extremity ; pharyngeal tube ear-shaped,
longitudinally plicate, recurved towards the posterior extremity ; anal
aperture postero-terminal ; cilia of cuticular surface short and even, dis-
posed in fine parallel longitudinal lines ; endoplast fusiform, subcentral ;
contractile vesicles two in number, separate from one another, often, as in
Paramcecium aurelia, exhibiting a stellate outline. Length i-ioo".

HAD. — Fresh water, among Nitella: Bombay (H. J. C.).

Mr. H. J. Carter, in his brief description of this interesting form,* having omitted
to confer upon it any other than a generic title, the author has much pleasure in

* 'Ann. Nat. Hist.,' Feb. 1856.

GENUS HELICOSTOMA. 501

connecting the name of its discoverer with its future specific denomination.
Although, as already intimated, the contour and habits of the animalcule agree
closely with those of Nassula and Helicostoma, certain points have been recorded by
Mr. Carter concerning its developmental manifestations which invite special atten-
tion. According to this observer the matured individuals become encysted within
the internodes of semi-decayed Nitellse, and then split up into two, four, or eight
cleavage masses, each of which is subsequently liberated from the cyst in a form
altogether identical with the parent Otostoma, but of smaller dimensions, and possess-
ing at this early stage a single contractile vesicle only. This process of multiplication
by encystment and segmentation, while of but rare occurrence among the more highly
organized Ciliata, commonly obtains among the Infusoria Flagellata, treated upon in
the preceding volume. Mr. Charles Stewart, of St. Thomas's Hospital, has recently
reported to the author the occurrence of an animalcule apparently indistinguishable
from Otostoma Carteri, from the neighbourhood of Plymouth, Devonshire. The
Sisyridion cochliostoma of Ernst Eberhard * is evidently closely allied to, if not
identical with, this same type.

GENUS VII. HELICOSTOMA, Cohn.

Animalcules free-swimming, elastic, more or less ovate, finely ciliate
throughout ; oral aperture ventral, circular, conducting to a tubular pharynx,
which, after proceeding obliquely backwards to the centre of the body,
terminates in a helicoidal flexure.

Excepting for the peculiar prolongation of the oesophagus with its terminal
helicoidal flexure, this generic type corresponds closely with the genus Nassula,
an intermediate form between the two being supplied by Mr. Carter's genus
Otostoma.

Helicostoma oblonga, Cohn. PL. XXVI. FIG. 54.

Body oblong or almond-shaped, rounded posteriorly, pointed anteriorly,
usually somewhat flattened, three or four times as long as broad ; cuticular
surface finely striate longitudinally and transversely; cilia short and fine,
evenly distributed, sometimes vibrating irregularly, and presenting a tufted
aspect ; oral aperture situated at a distance of about one-fourth of the length
of the whole body from the anterior extremity, pharyngeal tube continued
obliquely backwards to the centre of the body, and there forming a loop-
like or helicoidal twist ; endoplast subcentral ; contractile vesicle postero-
terminal. Length 1-125" to 1-75".

HAB. — Salt water. Movements swift, rotatory.

This species, described, in company with many other interesting marine types,
by Dr. Ferdinand Cohn in the ' Zeitschrift fur Wissenschaftliche Zoologie ' for the
year 1866, is referred to by its discoverer as apparently coinciding to some
extent with the Leucophra signata of O. F. Mu'ller, but of which the figure and
description given are not sufficiently explicit for actual identification. The transverse
striae of the cuticular surface, referred to in the foregoing diagnosis, are much less
conspicuously developed than those taking a longitudinal direction, and are to be
defined only with a careful adjustment of a high magnifying power, constituting in
this respect a test-object equal to that of the cross-striation of the diatom Pleurosigma
attenuatum.

' Oster-Programm der Realschule zu Coburg,' 1862.

502 ORDER HOLOTRICHA.

Fam. HI. TRACHELOPHYLLID-S3, S. K.

Animalcules free-swimming, ciliate throughout, more or less flask-
shaped ; oral and cuticular cilia alike, the oral aperture perforating the
extremity of the narrower anterior region, which is frequently highly
elastic and extensile.

GENUS I. TRACHELOPHYLLUM, C. & L.

Animalcules elastic, flattened, lanceolate or flask-shaped, having an
attenuate neck-like portion, the apical extremity of which is separated by
an annular constriction from the preceding part, and is perforated at its
apex by the oral aperture, as in the genera Lacrymaria and Trachelocerca,
but has no circlet of larger cilia ; pharyngeal passage tubular, conspicuously
developed ; contractile vesicle single, situated close to the postero-terminal
anal aperture.

Claparede and Lachmann have founded the genus Trachelophyllum on the type
first described by Perty under the title of Trachdius apiculatum, separating it from
the last-named generic group on account of the terminal position of the oral aperture.
The animalcules are further distinguished from those of Lacrymaria, which they still
more nearly approach, by their compressed form and the absence of the annular
circlet of stouter cilia at the anterior or oral region. As a consequence of their
flattened contour, their movement in the water differs considerably from those of
the cylindrical Lacrymaria. This in the type-species, T. apiculatum, consists
chiefly of a smooth, gliding motion, after the manner of Chilodon and Loxo-
phyllum, in place of rotation on their axis as obtains in Lacrymaria and Phialina.
The neck in Trachelophyllum, while possessing a considerable amount of elasticity,
is inferior in this respect to Trachelocerca.

Trachelophyllum apiculatum, Perty sp. PL. XXVI. FIGS. 61 AND 62.

Body flattened, lanceolate ; neck long, slender, and highly extensile,
nearly equal in length to the body, perforated throughout the greater
portion of its length by a narrow, straight, somewhat obscure pharyngeal
tract, the walls of which are faintly striate longitudinally ; cuticular surface
entirely but thinly clothed with moderately long cilia, whose action is
somewhat irregular and independent ; contractile vesicle single, spherical
or rosette-shaped, posteriorly situated ; endoplasts multiple, ovate, two or
four in number. Length of body 1-144." HAB. — Pond water.

This animalcule is identical with the Trachelius apiculatum of Perty. From two to
as many as four nuclei or endoplasts were observed in the specimens as examined
by Claparede and Lachmann, though the former and smaller number only is
ascribed to it by Wrzesniowski. The character and varied aspect of the contractile
vesicle under the respective conditions of systole and diastole, and during the
passage of excreta through the terminal anal aperture, has formed the subject
of careful investigation by the last-named authority,* the results arrived at yielding
the strongest possible evidence in demonstration of the non-possession by this

* A. Wrzesniowski, "Anatomic der Infusorien," ' Archiv fur Mikroskopische Anatomic*
Bd. v., 1869.

GENUS ENCHELYODON. 503

structure of a differential bounding wall or membrane, as also of its non-occupation
of a restricted position in the substance of the cortex. At the time of fullest
diastole a variable number of minute transparent lacunae filled with water make
their appearance round the border of the contractile vesicle, communicating to it
a rosette-shaped 'contour, and remain as small independent vacuoles after the
contents of the central reservoir have been discharged, these then coalesce, and,
increasing in size, assume the same form and pursue a like course as the water
globule or vacuole just discharged. The food-matter, after the extraction of its
nutrient properties, is collected in the form of a globular pellet at the posterior
extremity of the body, and on its way towards and through the anal aperture
temporarily dislodges the contractile vesicle, forcing it to a considerable distance
forwards from its original position, but to which it again returns after the evacuation
of the excreta.

Trachelophyllum pusillum, C. & L.

Body elongate, flask-shaped, the anterior or neck-like portion very little
narrower than the remainder of the body, four and a half times as long as
broad ; contractile vesicle single, postero-terminal ; endoplasts two in number,
elongate-ovate. Length of body 1-625". HAB. — Stagnant water.

Claparede and Lachmann regard this form as probably identical with the
Trachelius pusillus of Perty.

GENUS II. ENCHELYODON, C. & L.

Animalcules free-swimming, elastic and changeable in form ; ovate or
pyriform, not produced anteriorly in a neck-like manner ; oral aperture
apical, followed by a well-developed membranous pharynx, the walls of
which are mostly longitudinally plicate ; anal aperture postero-terminal ;
cuticular surface finely and entirely ciliate throughout. Inhabiting salt and
fresh water.

In constructing this genus upon the type next described, Claparede and
Lachmann left it in some doubt whether the walls of the conspicuous tubular
pharynx were simply membranous and longitudinally plicate, or whether they were
indurated or strengthened by a cylindrical fascicle of rod-like teeth, as in Nassula
and Prorodon. Assuming the balance of evidence to be in favour of the latter
of these two hypotheses, they placed it in close vicinity to Prorodon, and from
which, indeed, they represent it as differing chiefly in the greater elasticity
and finer ciliation of the cuticular investment, and in its slower movements.
Wrzesniowski, however, who has more recently made this type the object of a
special investigation,* has decided that the pharynx is membranous and longi-
tudinally plicate, as half-anticipated by Claparede and Lachmann, this being demon-
strated by the circumstance that the tube with its plications becomes bent upon
itself, or in a sinuous manner, during the contractions of the animalcule. Accepting
Wrzesniowski's interpretation, the natural position of Enchelyodon is evidently close
to that of Trachelophyllum, from which it would, indeed, appear to differ only in the
absence of a differentiated and elastic neck-like portion.

Enchelyodon farctus, C. & L. PL. XXVI. FIGS. 51-53.

Body elastic, ovate and somewhat flattened, slightly narrowest anteriorly,
more than twice as long as broad ; pharyngeal passage long and narrow,

* ' Archiv fur Mikroskopische Anatomic,' Bd. v., 1869.

504

ORDER HOLOTRICHA.

extending backwards to about one-third of the length of the body, its walls
plicate longitudinally, the anterior border projecting slightly beyond the
front margin of the body ; contractile vesicle single, spherical or rosette
shaped, situated posteriorly, close to the anal aperture ; endoplast band-like,
sinuous ; cuticular surface longitudinally striate ; cilia very short and fine.
Length of body 1-125". HAS.— Bog water: Berlin (C. & L.).

The contractile vesicle of this species has been shown by both Claparede and
Wrzesniowski to exhibit phenomena closely corresponding with what has been
already described of Trachelophyllum apiculatum, a portion of the accumulated
fluid being driven at the time of systole into minute rounded sinuses, the contents
of which afterwards coalesce together, and, increasing in volume, present all the
characteristics of the preceding vacuole. These metamorphic phenomena exhibited
by the contractile vesicle in Trachelophyllum and Enchelyodon, are directly com-
parable with the stellate modifications of this same structure already recorded of the
two genera Paramacium and Otostoma.

As shown by Wrzesniowski, a minute pore or aperture places the central lacuna
of the contractile vesicle of Enchelyodon farctus in direct communication with the
outer water. The aspect of this vesicle, in its fully dilated rosette-shaped condition,
showing its central pore-like aperture, is reproduced from Wrzesniowski's delineations
at PL XXVI. Fig. S3-

Enchelyodon elongatus, C. & L. PL. XXXII. FIG. 17.

Body attenuate, clavate, four or five times as long as broad, the anterior
half narrowest ; pharynx simple, short, and tubular ; contractile vesicle
single, spherical, posteriorly located ; endoplast central, oval ; cilia fine,
short, and evenly distributed. Length unrecorded.

HAB. — Salt water : Norwegian coast (C. & L.).

Although not mentioned in the description, Lachmann's figure of this species
indicates the presence of several symmetrically placed reflected setae, four on each
side, at the anterior extremity or oral region of the body. Should these setae
really exist, this form would seem to demand a generic title separate from that of
Enchelyodon for its reception.

GENUS III. UROTRICHA, C. & L.

Animalcules free-swimming, ovate or elliptical, entirely ciliate, motion
of cilia irregular and independent; oral aperture apical, terminal, a single
long, projecting springing-hair or seta developed at the posterior extremity.
Inhabiting fresh water.

The motion of the cilia in the representatives of this genus is peculiar, and
serves at a glance to distinguish them from those of the ordinary Holotrichous
types. Instead of vibrating in rhythmical cadence, each cilium waves in-
dependently and apparently without any order, the ciliary system a;A a whole
consequently assuming a comparatively irregular and untidy aspect. In creating
the genus Urotricha, Claparede and Lachmann remark that Professor Johannes
Muller had indicated the possible identity of their Urotricha farcta with the
Pantotrichum lagenula of Ehrenberg. M. Lieberkuhn, however, has supported
them in regarding the two forms as separate. Having frequently encountered the
animalcule described by Ehrenberg under the last-named title, the author is likewise
enabled to establish its distinctness from the species introduced by the Genevan
authorities, though it is obviously desirable to refer it to the same generic group.
The original genus Pantotrichum of Ehrenberg includes, in addition to P. lagenula,

GENUS UROTRICHA. 505

various minute entirely ciliate forms too indistinctly characterized for present
identification, and in none of which is mention made of the terminal springing-
hairs upon which the genus Urotricha is mainly founded.

Urotricha farcta, C. & L. PL. XXVII. FIG. 2.

Body ovate or ellipsoidal, surface of cuticle coarsely and obliquely
striate ; cilia short and evenly distributed, posterior springing - hair
obliquely directed when at rest, about equal to the body in length ; oral
aperture perforating a small circular prominence at the anterior extremity.
Contractile vesicle single, spherical, posteriorly situated ; endoplast ovate,
subcentral. Length 1-1250". HAB. — Pond water and in infusions.

The movements of this animalcule are of two kinds, and somewhat remarkable.
In its more ordinary mode of progression it swims slowly in a forward direction,
describing circles of a considerable diameter, the organs of propulsion on such
occasions being the irregularly vibrating cuticular cilia ; now and then, however,
this more even locomotion is interrupted by a spasmodic leap to one side or in some
other direction, the motion in this instance being accomplished by the posterior
seta or springing-hair. According to its discoverers, the oral aperture of this
species is capable of slight protrusion anteriorly in a lip-like manner, and in a way
apparently according with that characteristic of Trachelophyllum apiculatum and
Enchelyodon farctum ; its walls are at the same time highly elastic, and permit the
passage of food-masses almost equal in size to its own body.

Urotricha lagenula, Ehr. sp. PL. XXVII. FIG. i.

Body flask-shaped or pyriform, attenuate in front, rounded posteriorly,
from one and a half to twice as long as broad ; cuticular surface smooth ;
cilia longest in the anterior region, moving independently ; posterior spring-
ing-hair always directed backwards in a straight line, exceeding the body in
length ; contractile vesicle single, spherical, posteriorly located. Length
1-570". HAB. — Pond and marsh water.

This species, apparently identical with the Pantotrichum lagenula of Ehrenberg,
differs from the preceding type, not only in its larger size, but in its flask-shaped
contour, in the greater development of the cilia in the anterior region, and in
the uniformly straight direction of the posterior springing-hair, which has, moreover,
a greater proportional length. In common with Urotricha farda, its movements
through the water consist of slow rotation on its longitudinal axis in circles
and in a forward direction, varied by occasional leaps from side to side after the
manner of a Halteria or Uronema. In examples obtained from marsh water in the
neighbourhood of Le Marais, Jersey, in company with Paranuzcium bursaria,
numerous green chlorophyll-granules occupied almost the entire space of the internal
endoplasm; this colouring-matter was doubtless derived from the inception of
zoospores, Thecomonads, and other chlorophylloid organisms which abounded in
the same locality. The almost invariable occurrence of this form in company
with Hal'-ria grandinella, has afforded the author grounds for suspecting that
Urotricha lagenula may eventually prove to be a developmental phase only of the
last-named animalcule.

Fam. IV. COLEPID-ffi, Ehrenberg.

Animalcules free-swimming, symmetrically ovate, persistent in form,
ciliate throughout, oral cilia slightly larger than those of the general
cuticular surface.

VOL. II. D

506 ORDER HOLOTRICHA.

GENUS I. COLEPS, Ehrenberg.

Animalcules more or less evenly ovate, persistent in shape, cuticular
surface usually longitudinally and transversely furrowed, and thus divided
into numerous symmetrical quadrangular facets or interspaces ; the quad-
rangular facets smooth and indurated, the narrow intervening furrows soft
and clothed with cilia ; oral aperture apical, terminal, surrounded with cilia,
of slightly larger size than those of the general surface; anal aperture
situated at the opposite or posterior extremity, the anterior and posterior
margins usually mucronate. Dividing by transverse fission. Inhabiting
salt and fresh water.

The genus Coleps is usually cited as one of the few ciliate infusorial
groups whose members may be described as perfectly symmetrical ; many of the
representatives of the family of the Prorodontidse or Trachelophyllidte already
described possess, however, an equal claim to such distinction. The cuticular
ornamentation of the various species of the genus Coleps has been somewhat
diversely interpreted by independent observers. Perty and Dujardin maintained the
opinion that the quadrangular facets are indurated, and the narrow intervening
furrows soft and clad with cilia. Claparede and Lachmann, however, upheld the
view first expressed by Ehrenberg, to the effect that the furrows are indurated, and
form a continuous symmetrical trellis-work, and that the quadrangular facets are of
softer consistence and support the cilia. Having recently examined examples of the
typical species, Coleps hirtus, with considerable care and the aid of the highest
available magnifying power, the present author unhesitatingly adopts the interpretation
of Dujardin and Perty. The facility and rapidity with which the animalcules of
this genus divide by transverse fission is of itself a point in favour of the view here
supported, for while the existence of a continuous trellis-like induration of the
cuticular • surface would offer a considerable obstacle to such transverse division,
it takes place naturally and with the greatest ease along the line of one of the
previously existing and softer intersecting furrows. Diesing, on very insufficient
grounds, has proposed to separate this genus into three, abandoning the original title
of Coleps altogether, and substituting in its place that of Pinacocoleps for C. inaimnis,
Cricocoleps for C. amphacanthus, while all the rest, including C. hirtus and Stein's
Plagiopogon eoleps, are collated together under the generic name of Dictyocoleps.
The artificial character of such a plan of grouping is self-apparent.

Coleps hirtus. PI. XXVII. FIGS. 3 AND 4.

Body ovate, subcylindrical, more or less barrel-shaped, about twice as
long as broad, rounded posteriorly, slightly narrower and truncate in front ;
the anterior margin denticulate, three spinous processes or cusps developed
at the posterior extremity ; cuticular surface divided into quadrangular
areas and presenting a reticulate aspect ; endoplast spherical, subcentral ;
contractile vesicle single, posteriorly situated, colour whitish or light brown.
Length 1-500" to 1-400".

HAB. — Pond water, among duckweed and Conferva.

This widely distributed species is subject to some variation in contour and aspect.
One of these varieties having a more elongate outline has received from Ehrenberg
the title of Coleps elongates, and another, with green-tinted parenchyma, that of
C. viridis ; both, however, are now accepted as being merely local phases of the
present type. The active scavengering habits and voracity of Coleps hirtus have been

GENUS COLE PS. 507

the subject of remark by numerous observers, a crushed Entomostracon, or any other
dead or decaying organic substance contained in the water abounding with this
animalcule, being surrounded and devoured with an amount of happy despatch
that, comparing small things with great, would scarcely disgrace a troop of jackals
collected around some desert carrion. It has been further remarked that the
contour of these animalcules becomes considerably distended after their enjoyment
of such a meal, a fact which of itself substantially supports the view here adopted
as to induration of the quadrangular areas only of the cuticle, such a distension being
altogether irreconcilable with a continuous and trellis-like hardening of the same
surface. In the examples recently examined by the author, it was noted that when
the animalcules were feeding or otherwise stationary, the cuticular cilia exhibit a
continuous irregular and altogether independent vibratory action ; the vigorous
natatory movements, on the contrary, appeared to be accomplished through the
agency of the more powerful oral cilia. It was further certified, in the course of
this examination, that the cortex or body-substance immediately subjacent to the
sculptured cuticle was independently and sparsely striate or grooved in a longitudinal
direction, the body in such case, regarded independently of the external layer,
presenting an elongate, ribbed, melon-like contour.

During the process of transverse fission the animalcules of this species, as
shown at PI. XXVII. Fig. 4, exhibit an altogether abnormal aspect. While the two
extremities retain their usual corrugated appearance, the newly developed central
area, having a median constriction, is entirely smooth, or marked only by the deeper
longitudinal furrows just referred to. So also, when the two moieties become
entirely separated, one half of each of these remains for a considerable interval
smooth and transparent, the anterior and posterior halves of the same animalcule so
contrasting with one another as to suggest the simile of a smooth acorn projecting
from its rugose cup.

Quite recently, May 1880, the author has obtained in abundance, from a
pond near Acton, in company withj:he Flagellate types Trepomonas agilis and Tra-
chelomonas volvocina, a variety of this form or a most closely allied species, in which
no cusps whatever were developed at the posterior extremity, the size, quad-
rangular corrugation, and deeper longitudinal lines or furrows being, in' common
with all other essential structural details, identical with what obtains in C. hirtus.
At the same time the consistence of the cortical layer seemed to be thinner and
more transparent than usually obtains in that species, permitting a clearer view
of the internal contents, which were chiefly coloured green through the ingestion of
food-matter. While the comparative length and breadth in the examples examined
averaged in most instances the proportions of two to one, much shorter and almost
subspheroidal specimens were not unfrequently encountered. This well-marked
variety should perhaps be properly referred to the genus Plagiopogon, next described.

Coleps uncinatus, C. & L. PL. XXVII. FIG. 6.

Body ovate, slightly flattened ventrally, two and a half times as long as
broad ; the anterior margin bearing two recurved uncini on the more
flattened ventral side, four acuminate cusps developed at the posterior ex-
tremity. Contractile vesicle single, posteriorly situated ; endoplast discoidal,
central. Length of body 1-380". HAB. — Fresh water.

Coleps fusus, C. & L. PL. XXVII. FIG. 5.

Body fusiform, subcylindrical, nearly four times as long as broad; the
anterior margin truncate, denticulate, attenuate and pointed posteriorly ; no
posterior cusps. Length 1-300". HAB.— Salt water.

D 2

508 ORDER HOLOTRICHA.

In their brief description and illustration of this type, Claparede and Lach-
mann mention that the rugose induration of the cuticular surface does not extend
quite to the posterior extremity of the body, but leaves a short, soft, terminal portion
exposed. This species was originally obtained by M. Lachmann at Glesnoes, on
the Norwegian coast.

Coleps incurvus, Ehr.

Body oblong, subcylindrical, slightly curved, terminating posteriorly in
five points. Length 1-430". HAB. — Fresh water, among Conferva.

Coleps amphacanthus, Ehr.

Body shortly ovate, cuticular surface divided by transverse furrows into
numerous annular indurated segments, the anterior margin unequally den-
ticulate, three strong spines or cusps at the posterior extremity. Length
1-280". HAB. — Fresh water.

GENUS II. PLAGIOPOGON, Stein.

Animalcules free-swimming, persistent in shape, oval, subcylindrical,
longitudinally furrowed ; oral aperture anteriorly siftiated, surrounded by a
circle of stiff setose cilia ; fine, hair-like, vibratile cilia clothing the remain-
ing cuticular surface ; no apical or posterior spines ; contractile vesicle and
anal aperture posteriorly located.

Plagiopogon coleps, Stein. PL. XXVII. FIG. 7.

Body ovate, subcylindrical, a little over twice as long as broad, longi-
tudinal furrows rather widely separated, the intervening spaces finely striate
transversely. Length 1-300". HAB. — Salt and fresh water.

This typical species of the genus Plagiopogon is founded by Stein * upon the
Holophrya coleps of Ehrenberg and the Coleps inermis of Perty. As delineated by
these two authorities, the animalcule resembles a Coleps hirtus devoid of posterior
spines, and having its surface furrowed in a longitudinal direction only.

GENUS III. POLYKRIKOS, Biitschli.

Animalcules free-swimming, persistent in shape, subcylindrical or barrel-
shaped ; oral aperture terminal, having issuing from it a long bristle-
like seta ; numerous annular shortly ciliate grooves transversely encircling
the body ; endoplasm enclosing irregularly disposed trichocysts (?).

Polykrikos Schwartzii, Butschli. PL. XXVII. FIGS. 8-10.

Body barrel-shaped, subcylindrical, slightly narrowed and truncate at
the two extremities, about twice as long as broad ; transverse ciliary zones,
eight to twelve or more in number, converging forwards on one side so as to
form an obtuse angle parallel with the projection of the succeeding ring ; the
border of the oral aperture four-lobed ; a long stiff seta, similar to the oral
one, produced obliquely forwards from the body at a distance of about

* 'Prager Lotos,' Bd. ix., 1859.

GENUS ENCHELYS, 509

one-third of its entire length from the anterior extremity ; trichocysts large
and conspicuous, irregularly disposed (?) ; endoplasts two in number,
elongate-ovate, placed usually one behind the other; contractile vacuole
posteriorly situated. Multiplying by transverse fission. Length 1-200".
HAB. — Salt water, Norwegian coast, and also at Kiel in brackish water.

This single representative species of the genus Polykrikos as established by
Biitschli, accords so closely in general contour, and in the position of the mouth, with
the members of the genus Coleps, the annulation of the cuticle more particularly ap-
proximating that of C. amphacanthus, that it appears desirable to retain it provisionally
in the same family group. The long seta projecting from the oral cleft is possibly
the homologue of the seta common to various members of the Hypotrichous genus
Trochilia. The feature usually regarded as the most abnormal and important in this
type is the enormous size of the contained trichocysts and the perfect correspondence
of these structures with the nematocysts or thread-cells of the Crelenterata or sea-
anemones and hydroid zoophytes. The impression conveyed by a reference to
Butschli's original description and drawings of these structures,* reproduced at
PI. XXVII. Figs 9 and 10, are, it must be confessed, not unmingled with the
suspicion that these so-called trichocysts have an entirely adventitious origin. Their
disposition within the interior of the endoplasm is altogether irregular, and such as
would occur if incepted as food-material. The species, furthermore, possesses
a marine habitat, and not improbably feasts upon the debris of defunct zoophytes in
the same manner as the more familiar Coleps hirtus preys upon the residual
detritus of fresh-water organisms. The thread-cells of the Coelenterate structures
would in the former instance be extensively engulfed, and would, under such
circumstances, present the aspect accredited to them by Biitschli. Until, therefore,
further evidence is forthcoming proving the extrusion of these so-called trichocysts
from the cuticular surface of Polykrikos, their admission in the foregoing diagnosis
must be regarded as purely provisional.

Fam. V. ENCHELYID^E, S. K.

Animalcules free-swimming, more or less ovate, ciliate throughout, oral
cilia slightly larger than those of the general cuticular surface ; cuticle soft
and flexible ; oral aperture terminal or lateral ; the anterior extremity of
the body never prolonged in a neck-like manner.

The group of the Enchelyidae, as here defined, while corresponding to some
extent with that of the Enchelia and Enchelina of Ehrenberg and Stein, has a much
more restricted limitation, the long extensile-necked Trachelocerca, Prorodon and its
allies, and Coleps with its indurated integument, being excluded and referred to
independent families.

GENUS I. ENCHELYS, Ehrenberg.

Animalcules free-swimming, elastic and changeable in shape, pyriform
or globose ; oral aperture situated at the termination of the narrower and
usually oblique truncate anterior extremity ; anal aperture at the opposite
or posterior termination ; surface of cuticle entirely but very finely ciliate ;
cilia longer and more easily distinguishable in the region of the mouth.
Inhabiting marsh and stagnant water.

* ' Archiv fur Mikroskopische Anatomic," Bd. ix., 1873.

5 I O ORDER HOLOTRICHA.

The animalcules of this genus, while somewhat resembling those of Holophrya,
are to be distinguished from the latter by their pointed and obliquely truncate
anterior extremity, and by the fringe of larger cilia that encircles the oral region.
The diagnoses and figures of the several species, as given by Ehrenberg, represent
them as having no cilia on the general surface of the integument, these structures,
while present, being so fine that they are liable to be overlooked unless glasses of
the highest defining power are employed in their examination. From Trichoda,
with which the animalcules of this generic group also closely correspond in form
and habits, they are to be distinguished by the absence of a vibratile membrane in
association with the oral fossa. The genus Enchdys of Dujardin does not cor-
respond with that of Ehrenberg, but includes forms rightly referable to the genus
Cydidium.

Enchelys farcimen, Ehr. PL. XXVII. FIG. 15.

Body transparent, pyriform, slightly curved, attenuate and obliquely
truncate anteriorly, inflated posteriorly, about one and a half times as long
as broad ; contractile vesicle single, spherical, posteriorly located; endoplast
oval, subcentral. Length of body i-iooo" to 1-430".

HAB. — Stagnant water and infusions.

The author has encountered a species agreeing in every respect with this form
but of smaller dimensions, in hay-infusions, the largest examples not exceeding the
thousandth part of an inch in length. The characteristic movements of these
animalcules consisted, when feeding, of routing about, snout downwards, among
the vegetable debris, as shown in the accompanying figure, and at other times
of swimming slowly through the water rotating on their longitudinal axis. In
common with the members of the genus Holophrya, this and the other species of
Endielys become considerably distorted through the inception of food-substances,
that may even exceed themselves in bulk, and also assume at will an entirely
spherical outline. In this latter condition the oral aperture becomes completely
obliterated, the position of the contractile vesicle only under these circumstances
assisting in the distinction of the anterior from the posterior region of the body.

Enchelys pupa, Ehr.

Body inflated, attenuated anteriorly, frequently filled with green gifanules.
Length 1-140". HAB. — Stagnant bog water.

Enchelys arcuata, C. & L. PL. XXVII. FIG. 14.

Body pyriform, attenuate anteriorly, perfectly transparent, cilia of general
surface very short and fine ; contractile vesicles numerous, four or five in
number, arranged in an arcuate manner along the ventral margin of the
body ; endoplast elongate-oval, subcentral. Length 1-300".

HAB. — Bog water.

Doubtful Species.

The so-called Hematozoon from the blood of Ceylon red deer, described and
figured by Dr. Boyd Moss in the ' Monthly Microscopical Journal ' for October
1871, is apparently referable to the genus Enchelys. The animalcules there
delineated exhibit roughly the characteristic aspect of the members of this genus,
though the cilia, probably through imperfect illumination, were visible only upon
the more pointed anterior half of the body. Their dimensions would appear to
correspond most closely with the smaller size of those of E. farcimen. While the
evidence given by Dr. Moss strongly favours the supposition that these ciliate

GENUS METACYSTIS— PERISPIRA— ANOPHR VS. 511

animalcules occupy a permanent position within the vital fluid of the mammal
named, further corroborative testimony in the same direction is much to be
desired.

GENUS II. METACYSTIS, Cohm

Animalcules free-swimming, symmetrically ovate or elongate, persistent
in form ; the entire cuticular surface clothed with fine vibratile cilia, with
the exception of a bare vesicular-like posterior portion ; oral aperture
anteriorly situated, encircled by a fringe of stouter cilia.

Metacystis truncata, Cohn. PL. XXVII. FIGS. 11-13.

Body ovate or elongate, subcylindrical, the posterior third or fourth
smooth and vesicular-like, the remaining portion transversely annulate, and
finely ciliate ; the anterior extremity abruptly truncate, bearing a circlet of
long, incurved cilia ; endoplast spherical, central. Length of most elongate
specimens 1-900". HAB. — Salt water, among decaying algae.

As recognized by Cohn in his description given of this species,* it would seem
by no means improbable that it is identical with the marine type figured and
described by O. F. Miillerf under the title of Trichoda paxillus, but which does
not appear to have been encountered by any subsequent observer.

GENUS III. PERISPIRA, Stein.

Animalcules free-swimming, symmetrically ovate, persistent in shape
but not encuirassed ; oral aperture at the anterior extremity ; cuticular surface
entirely and finely ciliate; a raised border, bearing the adoral cilia,
extending in a spiral manner from the anterior extremity round the body
towards the posterior end ; anal aperture and contractile vesicle postero-

terminal.

Perispira ovum, Stein. PL. XXVII. FIG. 18 (?).

Body ovate, longitudinally striate, about twice as long as broad, oral
aperture presenting the form of a transverse fissure; endoplasm usually
filled with chlorophyll-granules. Dimensions unrecorded.

HAB. — Fresh water.

Stein suggests that this species is possibly identical with the Holophryoa vum of
Ehrenberg; the elastic character of the parenchyma and cuticular covering in that
type, as compared with Stein's diagnosis, would seem, however, to scarcely favour this
interpretation. The accompanying figure, PI. XXVII. Fig. 18, represents an ani-
malcule apparently closely allied to it if not identical with Stein's species, delineated
in the manuscript notes of Bombay Infusoria kindly placed at the author's
disposal by Mr. Carter ; the conspicuously larger size of the adoral spire of cilia
affords perhaps sufficient grounds for its recognition as a second species of the
genus Perispira.

GENUS IV. ANOPHRYS, Cohn.

Animalcules free-swimming, persistent in shape but highly flexible,
elongate-ovate, rounded posteriorly, the anterior extremity pointed, more or

* " Neue Infusorien im Seeaquarium," ' Zeitschrift fur Wissenschaftliclie Zoologie,' Bd. xvi., 1866.
t ' Animalcula Infusoria,' 1786.

5 I 2 ORDER HOL O TRICHA .

less curved ; oral aperture ventral, remote from the apical extremity, of
oblong shape, followed by a short, tubular pharynx ; cuticular surface entirely
ciliate ; a fascicle of longer and stouter cilia issuing from the oral cleft ;
endoplast and contractile vesicle conspicuous.

According to Cohn, excepting for the absence of the minute enclosed oral mem-
brane, the representatives of this genus closely correspond with those of Trichoda as
modified by Stein ; the chief distinction between the two being that, while in Triehoda
the oral cilia form a small wreath round the subterminal buccal aperture, in Anophrys
they depend in a fascicular manner from this structure. The still closer affinity of
the type-form of this generic group with Colpoda is self-evident.

Anophrys sarcophaga, Cohn. PL. XXVII. FIGS. 16 AND 17.

Body elongate-ovate or clavate, subcylindrical, rounded posteriorly,
pointed and curved anteriorly, from three to four times as long as broad ;
pale amber colour ; oral aperture situated on the ventral surface at a distance
of one-third of the length of the entire body from the anterior extremity,
bearing a fascicle of about eight or nine large cilia ; cuticular surface
furrowed longitudinally and transversely ; the cilia clothing the pointed
anterior extremity of larger size than those of the remaining portion of the
body, which are very fine and difficult to see ; endoplast central, spherical,
of large size ; contractile vesicle postero-terminal. Length 1-400".

HAB. — Salt water, with decaying animal matter.

As recognized by Cohn,* this species, excepting for the character of the oral cilia,
closely resembles the Trichoda (Leucophrys) carnium of Ehrenberg, a species occur-
ring in putrescent infusions, and in water from manure-heaps ; the oral aperture in
this latter type would seem, however, to be more nearly terminal. Reference is
made by Cohn to a long tail-like seta at the posterior extremity, but is not indicated
in his drawings. The fascicle of oral cilia in rapid motion is described as present-
ing the appearance of an undulating membrane.

GENUS V. COLPODA, Ehrenberg.

Animalcules free-swimming, persistent in shape, ovate or reniform,
compressed ; oral aperture ventral, lying in a cleft-like depression at some
little distance from the anterior extremity, having no undulating membrane,
but giving origin to a brush-like tuft of longer cilia ; pharynx absent or
rudimentary ; cilia of the general surface very fine, sometimes conspicuous
only towards the anterior extremity of the body. Inhabiting fresh and
salt water and infusions.

Colpoda cucullus, Ehr. PL. XXVII. FIGS. 19-23.

Body subreniform, one and a half times as long as broad, rounded and
inflated posteriorly, pointed anteriorly and recurved towards the ventral
aspect ; cilia of the oral region projecting in a tongue-shaped or tuft-like
manner from the oral fossa, the shorter cilia of the general surface con-
spicuous only towards the anterior extremity of the body; endoplast

* 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xvi., 1866.

GENUS TILLINA. 513

spherical, subcentral; contractile vesicle spheroidal, of large size, posteriorly
located. Length of body 1-280".
HAB. — Fresh water and infusions.

The distinction between this form and the Colpoda cuculhis of Dujardin, or
Colpidium cuculhis of Stein, is explained in the description given of the last-named
species. Although appearing under ordinary magnification, and formerly pronounced
to be ciliated only at the anterior extremity, there is no longer room for doubt that the
entire surface of the body of this animalcule is also finely ciliate. The multiplica-
tion by fission of this species has been described at length by the last-named author,
this process in all instances, according to Stein's observations, being preceded by
encystment. Within its cyst the animalcule divides variably into either two, four,
eight, or as many as sixteen, spore-like bodies, which ultimately escape through the
rupture of the wall of their prison-house in a form which, while smaller, is in all
respects identical with that of the parent animalcule. Similar reproductive pheno-
mena have been recorded in connection with the genus Otostoma, but are at the
same time rare among the Ciliata, though of almost universal occurrence among
the more simple Flagellata. No act of conjugation or fusion of two animalcules is
mentioned by Stein as necessarily preceding the process of encystment and sporular
form of multiplication as above described.

Colpoda parvifrons, C. & L.

Body ovate, nearly twice as long as broad, rounded at both extremities
but widest posteriorly, the anterior end not recurved ventrally ; the outer
surface of the body distinctly though finely ciliate; contractile vesicle
posteriorly situated but not precisely terminal as in C. cuculhis. Length of
body 1-600". HAB. — River water : Spree, near Berlin (C. & L.).

Colpoda pigerrima, Cohn. PL. XXVII. FIG. 24.

Body elliptical, pointed at each extremity, about three times as long as
broad, the anterior end most attenuate and curved towards the ventral
aspect ; oral cleft at a distance of about one-third of the entire length of
the body from the anterior extremity; cuticular surface subdivided by
longitudinal and transverse striations into minute quadrate areas ; cuticular
cilia very short and fine, of equal size throughout, oral cilia forming a
projecting recurved tuft; contractile vesicle situated close to the base of
the oral cleft. Length 1-780".

HAB. — Sea water with decaying animal matter.

The greater proportional length, surface ornamentation, and position of the
contractile vesicle readily distinguish this type from the two preceding species.

GENUS VI. TILLINA, Gruber.

Animalcules free-swimming, persistent in shape, subreniform ; oral
aperture ventral, followed by a long, curved pharynx ; cuticular surface
entirely clothed with very fine vibratile cilia, a circle of longer cilia developed
round the oral aperture and continued down the pharyngeal
endoplast and contractile vesicle conspicuous.

'- ^^ f ^

'«&£

lujtUBRARYJ'

• \ /

5 1 4 ORDER HOL 0 T RICH A .

Tillina magna, Gruber. PL. XXXII. FIG. 13.

Body subreniform or bean-shaped, compressed, rather over twice as long
as broad ; an irregular, broad, lobate process developed from the dorsal
aspect of the posterior extremity and interrupting the symmetry of this
region ; oral aperture ventral, subcentral, followed by a tubular, strongly
recurved pharynx, whose walls are conspicuously ciliate throughout ; oral
and pharyngeal cilia considerably larger than those covering the general
cuticular surface ; cuticular surface smooth, or finely and sparsely striate
longitudinally, its deeper layer apparently striate radially, an aspect due
most probably to the enclosure of trichocysts ; endoplast elongate-ovate,
situated in the anterior body-half; contractile vesicle posteriorly located,
intrenching partly on the irregular lobate process. Length 1-125".

HAB. — Fresh water.

This species, described by Dr. August Gruber, together with several other
interesting forms, in the ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxxv., 1879,
and translated in the 'Journal of the Royal Microscopical Society' for April 1880, is
regarded by its discoverer as exhibiting a type of structure intermediate between
Paramarium and Colpoda. In the peculiar form of pharynx, however, it much
more closely approaches Conchophthirus, but is necessarily referred to the present
family group on account of the more conspicuous development of the oral cilia.
Reproduction accompanied by encystment and subdivision into four equal spore-like
masses after the manner of Colpoda, has been observed. In the accompanying
drawing the anterior and posterior regions have been accidentally reversed.

Fam. VI. TRACHELOCERCnXZE, S.K.

Animalcules free-swimming, flask-shaped or elongate, soft and flexible,
ciliate throughout, the oral cilia slightly exceeding in size those of the
general cuticular surface ; the anterior extremity usually prolonged in a
neck-like manner, an annular groove or furrow often present near the apical
extremity ; oral aperture terminal or subterminal.

GENUS I. TRACHELOCERCA, Ehrenberg.

Animalcules highly elastic and changeable in form, the anterior portion
produced as a long, flexible, narrow, neck-like process, the apical termination
of which is separated by an annular constriction from the preceding part,
and is perforated apically by the oral aperture ; the entire cuticular
surface finely and evenly ciliate, a circle of longer cilia developed round
the oral region. Anal aperture postero-lateral or subterminal. Contractile
vesicles usually multiple, irregularly distributed. Inhabiting fresh and salt
water.

The diagnosis of the genus Trachelocerca as above given, and as constructed in
accordance with the results of more recent investigation, differs materially from that
first introduced by Ehrenberg. In accordance with the representations of this last-
named authority, the cuticular surface of the animalcules of this genus was entirely
devoid of cilia, and the oral aperture, instead of being situated at the apical extremity
of the anterior neck-like prolongation, as is now determined, was pronounced to be
located in the annular groove that separates the extreme anterior portion from the

GENUS TRACHELOCERCA. 515

remainder of the body, and which antero-lateral position of the mouth forms the
essential characteristic of the genus Phialina.

By Dujardin, and Claparede and Lachmann, it has been considered desirable to
amalgamate the genus Trachelocerca with that of Laerymaria, and to retain the last-
named title only, the single hitherto well-characterized member of the former genus
T. olor, being represented by them as differing too slightly from the ordinary
Lacrymarice to claim independent generic recognition. It has been decided
here, however, to retain both of these two titles, numerous animalcules being
now known that form collectively two natural groups, between which it is easy
to discriminate when thus separated, but whose specific identification would be
attended with much inconvenience were they collectively compared. In pursuance
of this decision, all those forms are retained in the genus Trachelocerca which agree
with T. olor in the possession of a specially elongate and highly extensile neck-like
anterior portion, in mostly having several irregularly distributed contractile vesicles,
and in the usually subterminal position of the anal aperture. In Laerymaria, on
the other hand, as typified by the L. lagenula of Claparede and Lachmann, there is
no specially elongate and elastic neck, the contractile vesicle is single and postero-
terminal, and the anal aperture exactly terminal and immediately behind the con-
tractile vesicle. It is further a fact of note that all the short-necked specific forms
hitherto discovered, and here referred to the genus Laerymaria, are strictly inhabi-
tants of salt water. While thus readily distinguishable in their adult conditions, a
developmental phase of Trachelocerca olor is presently shown to correspond in a
remarkable manner with the typical adult condition of Laerymaria lagenula.

Trachelocerca olor, Mull. sp. PL. XXVII. FIGS. 29-31.

Body subfusiform, usually attenuate posteriorly, the neck-like anterior
portion exceedingly elastic and contractile, often, in extension, equal to four
or five times the length of the body ; cuticular surface finely ciliate, obliquely
striate in two directions ; contractile vesicles two or three in number ; endo-
plast double, with a distinct endoplastule. Length of extended body
1-140". HAB. — Pond water.

This species was one of the earliest known infusorial forms, it having been
first figured and described by Baker in the year 1752 under the title of the " proteus,"
while in Miiller's works it receives the three names of Vibrio pro fats, V. olor, and
V. cygnus ; its relegation to the genus Trachelocerca was subsequently accomplished by
Ehrenberg. The aspect of the animalcules of this species, as they swim gracefully
through the water, extending and contracting their attenuate and wonderfully exten-
sile necks, or thrusting them from side to side in search of food among the con-
fervoid filaments or vegetable debris which they usually affect, is, as implied by
its specific title, not unlike that of a swan, or is perhaps still more suggestive
of the restored figures of the long-necked mesozoic Plesiosauri, contained in
popular geological treatises. It has been frequently observed by the present
author that two individuals of this species are almost invariably found in close
proximity, and appear to be guided in all their movements by a certain com-
munity of action. The Trachelocerca viridis, T. linguifera, and T. biceps, and also
the Laerymaria proteus of Ehrenberg, are regarded by Claparede and Lachmann
as varieties only, or imperfectly observed examples, of this exceedingly protean
and variable species. In this manner the first-named is distinguished merely by
the presence of engulfed and incorporated chlorophyll-granules ; T. biceps would
be a monstrosity with a double neck, or a zooid undergoing longitudinal fission ;
while the variety with a rounded posterior extremity, described under the title
Laerymaria proteus, probably represents an animalcule whose contour is abnormally
rounded and inflated by the ingestion of food-particles. The Trachelocerca linguifera
of Perty, said to differ from T. olor in the form of the oral region, which is described
as being surmounted by a movable flap or tongue-like process, practically corre-

5 1 6 ORDER HOLOTRICHA.

spends with the normal aspect of this region in the present species. Claparede and
Lachmann observe of the terminal oral region of this animalcule that the circlet of
oral cilia is capable of being adpressed against the distal extremity, and assists in
the prehension of food-particles. Under high magnification the walls of the conical
oral fossa are shown to be longitudinally striate, and are probably plicate in a
manner closely corresponding, though in a more marked degree, to what obtains in
the two genera Trachelophyllum and Enchelyodon.

In a gathering containing this animalcule, T. olor, in abnormal abundance,
examined by the author so recently as February 1880, it was observed that a form
corresponding in external contour with the marine Lacrymaria lagenula of Claparede
and Lachmann, was equally plentiful; furthermore, that every intermediate con-
dition, having gradually lengthened and more or less flexible neck-like prolonga-
tions, were intermingled, the two extreme forms being thus closely amalgamated with
one another. Finally, by patient watching, the short, stiff-necked Lacrymaria-\\k.Q
zooids were found to develop into the long and graceful necked Trachdocercce, the
primary simply flask-shaped zooid gradually acquiring a distinct attenuate and
extensile neck, the two being thus demonstrated to be transitional phases only of the
same species. The observation of this type being still further prolonged, it was at
length determined that the short-necked zooids were the derivatives by transverse
fission of an ordinary long-necked animalcule, and represented the hinder moiety of
the fissive process pending the subsequent rapid development of the characteristic
neck. .

Trachelocerca versatilis, Mull. sp. PL. XXVII. FIG. 33.

Body attenuate fusiform, pointed posteriorly ; neck long and thread-
like, its distal extremity expanded and conspicuously ciliated underneath ;
cilia of the general cuticular surface exceedingly fine and difficult to detect.
Length, when extended, 1-40"; retracted, 1-120".

In the autumn of the year 1870, a salt-water species of Trachelocerca was obtained
by the author at Bognor, Sussex, evidently identical with the form briefly characterized
as above by both O. F. Miiller and Dujardin under the respective titles of Trichoda
and Lacrymaria versatilis. Unfortunately, the amount of attention requisite for the
framing of a more complete diagnosis was not bestowed upon it at the time.
Compared with T. olor, with which Perty has proposed to identify this species, it
may, however, be stated that the body was much more narrow and attenuate, and
the distal extremity of the neck or oral region proportionally thicker ; the subter-
minal circle of oral cilia was likewise observed to be more obliquely set, a circum-
stance communicating to this region, when seen in profile, the aspect of being
ciliated underneath, attested to by the authorities quoted. In the great length and
elasticity of the neck-like prolongation this species rivals the form previously
described.

The salt-water Trachelocerca sagitta of Ehrenberg, briefly described as of fusiform
contour, with a very long neck, colour white, head terminal and opaque, length 120",
would seem to correspond closely with Trachelocerca versatilis, or may be identical
with Cohn's T. phcenicopterus.

Trachelocerca phcenicopterus, Cohn. PL. XXVII. FIG. 32.

Body elongate, ribbon-like, flattened, highly elastic and retractile, finely
annulate transversely, prolonged anteriorly into an attenuate, trans-
parent neck, and posteriorly into a long, pointed, tail-like portion ; oral
aperture terminal, circular, with a rigid annular border, followed by a funnel-
shaped pharyngeal cleft ; the distal end of the neck slightly widened, its

GENUS LA CR YMA RIA . 517

extremity abruptly truncate ; contractile vesicles multiple, lineally disposed.
Length of body when most extended 1-24", retracted 1-60".
HAB. — Salt water.

The rigid annular border surrounding the apical extremity in this form would
seem to take the place of the conical prominence in the ordinary species, unless it is
that Cohn's figure and description apply to examples in which at the time of
examination this usually conspicuous structure was concealed by invagination.
Although a single contractile vesicle only is seen in the figure here reproduced
from Cohn's original account of this species,* the two other examples delineated by
this authority exhibit respectively two and eight of these structures, and which in the
last instance are disposed at even intervals throughout the centre of the thicker
central region of the body. In one example the endoplasmic layer has a vacuolar
or reticulate aspect somewhat analogous to that of Trachdius ovum.

Trachelocerca tenuicollis, Quenn.

Body elongate-lanceolate, pointed posteriorly ; neck long and very
slender, scarcely dilated at the apex ; cuticular surface finely ciliate, feebly
striate longitudinally ; contractile vesicle posteriorly situated ; endoplast
subcentral. Length in extension 1-75". HAB. — Salt water.

GENUS II. LACRYMARIA, Ehrenberg.

Animalcules free-swimming, more or less cylindrical, clavate or flask-
shaped, moderately elastic, the anterior end narrowest, the apical extremity
conical in outline, and separated from the remaining portion of the body by
an annular constriction, the intervening region not produced into a separate,
slender, and highly elastic neck-like region, as in Trachelocerca ; oral aperture
surrounded by one or more ciliary circlets, perforating the apical extremity of
the anterior conical prolongation ; the cuticular surface finely and entirely
ciliate ; contractile vesicle single, postero-terminal ; anal aperture situated
immediately behind the contractile vesicle. Mostly inhabiting salt water.

The Lacrymaria lagenula of Claparede and Lachmann is here adopted as the
type-form of this genus, to which two additional forms possessing the same broad
general characters are here added. The Lacrymaria proteus, L. olor, L. gutta,
L. rugosa, L. tornatilis, and L. farcta, of Ehrenberg, Perty, and Dujardin, are long
flexible-necked animalcules, referable, so far as it is possible to identify them, to the
genera Trachelocerca and Amphileptus.

Lacrymaria lagenula, C. & L. PL. XXVII. FIG. 34.

Body clavate or flask-shaped, attenuate anteriorly, nearly four times as
long as broad ; cuticular surface obliquely striate, finely and entirely ciliate,
a single circlet 'of longer cilia surrounding the oral region ; contractile vesicle
single, spherical, postero-terminal ; endoplast elongate-oval, subcentral.
Length of body 1-350". HAB. — Salt water : Norwegian coast (C. & L.).

As suggested by its discoverers, the contour of this animalcule corresponds
remarkably with that of a soda-water bottle, the posterior inflated portion answering

'Neue Infusorien im Seeaquarium," 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xvi., 1866.

5 1 8 ORDER HOLOTRICHA .

to the body, the more attenuate anterior portion to the neck, while the conical
extremity, separated off by the annular ciliated groove or furrow, may be said to
represent the cork. Under the name of Lacrymaria versatilis Quennerstedt * has
figured and described a marine animalcule which agrees closely with the form under
notice, excepting that its contour is slightly more slender and attenuate, the length
equalling as much as six times that of the greatest breadth. It has the same elon-
gate, bottle-shaped contour ; the cuticular surface is obliquely channelled or striate
in a similar manner, and the endoplast and contractile vesicle correspond similarly
in both character and position. Quennerstedt proposes to identify this variety, or
possibly independent type, with the Trichoda versatilis of O. F. Miiller, which is,
however, undoubtedly rightly referable to the preceding genus. This is shown both
by Miiller's description in the following terms of the movements of the animalcule
in the water : " Motus natando celerrimus, collum hinc et illinc pro lubilu dirigit"
and by his additional indication in the figures of the species of the attenuate and
extensile character of the neck.

Lacrymaria coronata, C. & L. PL. XXVII. FIG. 28.

Body elongate-clavate, slightly narrowed anteriorly, nearly five times as
long as broad ; two ciliary circlets developed around the apical extremity,
the anterior one bearing the longest cilia, each occupying an annular
groove or furrow; surface of cuticle obliquely striate, entirely and finely
ciliate ; contractile vesicle spherical, postero-terminal ; endoplast elongate,
band-like. Length of body 1-150".

HAB. — Salt water, Norwegian coast.

The double circlet of cilia at the apical extremity and band-like form of the
endoplast, independently of the greater porportionate length of the body, assist in
distinguishing this type from the preceding one. The characteristic apical region
only of this animalcule is delineated in the accompanying figure.

Lacrymaria Cohnii, S. K. PL. XXVII. FIGS. 25-27.

Body highly elastic and changeable in form, when extended oblong
cylindrical, slightly broader and somewhat truncate anteriorly, about four
times as long as broad, contracting from this to an almost spherical con-
tour, the posterior third often flattened out and twisted like the blade of a
ship's screw ; surface of cuticle finely ciliate throughout, faintly striate lon-
gitudinally ; body usually opaque through the enclosure of numerous fat-
like corpuscles; contractile vesicle largely developed, postero-terminal.
Length 1-240". HAB. — Salt water.

The above specific title is herewith conferred upon the form figured and described
by Cohn, in his 'Neue Infusorien im Seeaquarium,' 1866, under the title of Lacry-
maria lagenula C. & L. From this last-named type it is evidently totally distinct.
The flask-like contour, with a tapering anterior extremity distinctive of that form,
would appear to be never assumed by the present animalcule, but in its place a highly
remarkable screw-like shape, which would scarcely have escaped the attention of
Claparede and Lachmann in connection with their species ; the surface of the cuticle
in Cohn's type is, further, entirely wanting in that conspicuous oblique striation,
and the general substance of the body would appear to be much more soft and con-
tractile. The figures given by Cohn, here reproduced, entirely support the views here
held relative to the invertile nature of the apical portion of the conical anterior

* ' Sveriges Infusoriefauna," tab. i. fig. 5, 1867.

GENUS PHIALINA . 519

prolongation; in two instances this part, Figs. 26 and 27, is shown to project con-
spicuously beyond the oral fringe of cilia, while in the other, Fig. 25, these cilia
seem to issue from the apical extremity itself, an aspect which would necessarily
result from the withdrawing inwards of this structure. The Trichoda ambigua of
O. F. Miiller * would seem to agree with this type in the flattened screw-like contour
of the posterior region of the body, and is possibly identical with it. At the same
time the body of Miiller' s species would appear to have a more elongate and
vermiform shape, and it is apparently not capable of contracting into a globular form.
Like the present species, it is an inhabitant of salt water.

GENUS III. PHIALINA, Ehrenberg.

Animalcules free-swimming, subcylindrical or flask-shaped, slightly
elastic, narrowest anteriorly, a portion of the yapical region separated from
the rest of the body, as in Trachelophyllum and Lacrymaria, by a circular
groove, and bearing a circlet of longer, usually reflected cilia ; the oral
aperture situated in the anterior annular groove, and not terminal as in the
two last-named genera ; cuticular surface finely and entirely ciliate ;
contractile vesicle single, adjacent to the postero-terminal anal aperture.

With the exception of the antero-lateral, instead of apical position of the mouth,
the animalcules of this genus correspond essentially with those of Lacrymaria, and,
unless the exact position of this aperture is seen and determined, are liable to be
confounded with them.

Phialina vermieularis, Ehr. PL. XXVII. FIGS. 36.

Body subcylindrical, ovate or pyriform, narrowest anteriorly, two and a
half times as long as broad, the -apical portion in advance of the annular
furrow short and broadly cylindrical, its anterior margin truncate and bear-
ing a single circlet of cilia, these cilia usually directed backwards ; oral
aperture opening on the annular furrow ; surface of integument smooth,
finely and entirely ciliate ; contractile vesicle single, spherical, postero-
terminal ; endoplast ovate, subcentral, obliquely directed. Length of body
1-240". HAB. — Pond water.

The lateral position of the mouth of this animalcule has been very clearly indicated
by Ehrenberg, but, as intimated by Claparede and Lachmann, the figure referred to
most probably depicts an example observed at the moment of engulfing food, the
organ at other times being difficult to recognize. By Ehrenberg and various earlier
writers the cuticular surface of Phialina, as in the case of Lacrymaria, Trachclocerca,
and other forms, is described as being entirely glabrous. More recent observation,
assisted by the employment of superior magnifying lenses, has, however, determined
the presence of fine cilia throughout its whole extent. The aspect of Phialina
vermieularis, with its reflected anterior circlet of larger cilia only visible, has been
not inaptly compared with that of a minute Echinorhynchus.

Doubtful Species.

The Phialina viridis of Ehrenberg, PI. XXVII. Fig. 37, is suspected by Claparede
and Lachmann to be a coloured variety only of P. vermieularis ; according to
Ehrenberg's figures, however, the body also is differently proportioned, the posterior

* 'Animalcula Infusoria,' p. 200, pi. xxviii. figs. 11-16, 1786.

520 ORDER HOLOTRICHA.

extremity being slightly narrower than the shoulder portion of the bottle-shaped
body, while the projecting neck is more attenuate. Colour bright green. Length
1-288".

GENUS IV. MARYNA, Gruber.

Animalcules ovate or cup-shaped, with an anterior projecting funnel-
shaped neck, which is cleft on its ventral aspect and fringed along its
anterior edge with a single row of long cilia ; finer vibratile Cilia distri-
buted over the whole cuticular surface ; oral aperture situated at the base of
the anterior cleft, followed by a fissure-like pharyngeal passage. Habits
social, secreting and inhabiting a common tubular zoothecium, to the walls'
of which they are not permanently united.

Maryna socialis, Gruber. PL. XXXII. FIGS, n AND 12.

Zoothecium dichotomously branched, granular and finely striate trans-
versely, narrower or constricted at the commencement of each bifurcation ;
colour light brown or yellowish; contained zooids projecting slightly from
their respective thecae ; cup-shaped, one and a half times as long as broad ;
the posterior border rounded, the anterior one truncate, with a centrally
developed, ventrally cleft, funnel-like neck, a cleft on the ventral aspect of
the anterior border corresponding with that in the neck ; pharynx continued
backwards to within a short distance of the posterior border; ante-
rior wreath of cilia very long and fine ; contractile vesicle situated near the
termination of the ventral cleft ; endoplast unobserved. Length 1-165".

HAB. — Salt water.

The position of this animalcule is obviously near Lacrymaria and Phialina,
from both of which it most conspicuously differs in its social habits and construction
of a common zoothecium. A translation of the original description of this species, as
figured and described by Dr. Gruber,* in common with various other, interesting
infusorial forms, is given in the ' Journal of the Royal Microscopical Society ' for April
1880. A closely corresponding branching zoothecium is constructed by the Hypo-
trichous type Stichotricha socialis, described by Dr. Gruber in the same serial.

GENUS V. LAGYNUS, Quennerstedt.

Animalcules free-swimming, elastic, more or less flask-shaped ; oral
aperture terminal, followed by a longitudinally plicate tubular pharynx ;
a circle of longer cilia surrounding the oral aperture, but not, as in Tra-
chelocerca and Lacrymaria, set in a distinct annular groove or furrow ;
general cuticular surface entirely ciliate ; contractile vesicle and endoplast
conspicuous.

Quennerstedt f has adopted as the type of this genus the Lacrymaria elegans of
Engelmann, | adding to it a second species observed by himself. The peculiar
structure of the pharyngeal tube, which approximates that of Trachelophyllum and

* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxxv., 1879.

t ' Sveriges Infusoriefauna,' 1867.

\ " Zur Naturgeschichte der Infusionsthiere," ' Zeit. Wiss. Zool.,' Bd. xi., 1862.

GENUS CHCENIA. 521

Enehelyodon, and the entire absence of a separated conical prolongation at the
anterior extremity, supply ample grounds for its generic isolation from Lacrymaria.

Lagynus elegans, Engl. sp. PL. XXVII. FIG. 35.

Body elastic, flask-shaped, about three times as long as broad, rounded
and widest posteriorly, produced anteriorly in a neck-like manner ; oral
aperture at the apex of this neck-like portion conducting to a funnel-shaped
longitudinally plicate pharynx ; cuticular surface coarsely ciliate, traversed
longitudinally by faint, widely separated striations, the more attenuate
neck-like portion exhibiting three or four transverse annulations ; con-
tractile vesicle single, postero-terminal : endoplast central, ovate, associated
with a laterally attached endoplastule. Length 1-150" to 120".

HAB. — Fresh water.

Conjugation, effected by the close application of the oral surfaces of two indi-
vidual zooids, was in one instance observed by Engelmann.

Lagynus laevis, Quenn.

The form and proportions of this animalcule, as figured by Quennerstedt, cor-
respond closely with those of L. elegans, but the cuticular cilia are much finer, and
the narrower, neck-like portion is not interrupted, as in that species, by transverse
annulations.

GENUS VI. CHCENIA, Quennerstedt.

Animalcules free-swimming, highly elastic, elongate or vermicular ; oral
aperture at the anterior extremity, widely dilated during the passage of food-
substances, otherwise inconspicuous ; cuticular surface ciliate throughout,
a brush-like tuft of larger cilia surrounding the apical or oral extremity.

Chcenia teres, Duj. sp. PL. XXVII. FIGS. 41-44.

Body linear-lanceolate or vermicular, highly flexible, ranging, according
to degree of extension, from about eight times to as much or more than
twenty-three times as long as broad, the posterior extremity obtusely
rounded, the anterior one conically pointed ; cuticular surface finely ciliate,
faintly striate longitudinally ; oral cilia forming a forward-directed, brush-like
tuft, a few slightly longer cilia developed at the posterior extremity ;
contractile vesicle single, postero-terminal. Length variable, 1 1 50" to 1 100"
when contracted, 1-50" to 1-30" when fully extended.

HAB. — Salt water.

In describing this type, and instituting a new genus for its reception, Quenner-
stedt * confers upon it the title of Chcenia vorax, but at the same time suggests the
possibility of its being identical with one of those widely diverse forms, the Enchelys
farcimen of Ehrenberg, the Enchelyodon elongates of Claparede and Lachmann, or
the Trachelius teres of Dujardin. Having recently encountered this animalcule in
sea water at St. Heliers, Jersey, the author is satisfied that Quennerstedt's con-
jecture with reference to the last-named species, is correct, and hence the specific
name originally given to it by Dujardin is here retained. In the examples personally

* ' Sveriges Infusoriefauna,' 1867.
VOL. II. E

522 ORDER HOLOTRICHA.

examined it was observed that the animalcules possessed the capacity of extend-
ing to a much greater length than is indicated in Quennerstedt's drawings, which
must be accepted as a comparatively contracted state ; the new figure, PL XXVII.
Fig. 40, as here given, more correctly illustrating its typical and fully extended con-
dition. The elasticity of the oral region is well represented in Quennerstedt's
delineations reproduced at Figs. 43 and 44.

The Trathelius striatus of Dujardin * is apparently a fresh-water variety of the
genus Chcenia ; its shape and proportions are identical with those of C. teres, but it is
of much smaller size.

Fam. VII. TRACHELIIDJE, Ehr.

Animalcules free-swimming, ovate or elongate, highly elastic, ciliate
throughout ; oral cilia slightly larger in size than those of the general
cuticular surface ; oral aperture situated at the base of a more attenuate
and often trunk-like anterior prolongation.

GENUS I. TRACHELIUS, Ehrenberg.

Animalcules free-swimming, ovate or subglobose, the anterior portion
produced in a snout or trunk-like manner, the oral aperture being situated at
the base of this anterior prolongation ; pharyngeal tract ^apparently ramify-
ing within the interior of the body, and presenting the aspect of a branched
alimentary canal, such appearance, however, being entirely due to the
highly vacuolar or reticulate character of the internal sarcode or endoplasm ;
anal aperture postero-terminal ; cuticular surface entirely and finely ciliate,
oral cilia differing but slightly in size from those of the general surface.

This genus is now limited to those forms only that coincide with Trachdius ovum
in the possession -ef an apparent internally ramified alimentary tract The numerous
other species formerly placed in it by the older writers are chiefly assignable to the
genera Amphileptus and Loxophyllum.

Trachelius ovum, Ehr. PL. XXVII. FIG. 38.

Body subglobose or ovoid, prolonged anteriorly in the form of a short,
flexible, trunk-like appendage, whose length does not exceed, and rarely
equals, the diameter of the body ; oral aperture succeeded by a short,
conical, longitudinally plicate pharynx, which is apparently continued as a
wide, central, longitudinal and tubular prolongation, giving off at right
angles numerous smaller, lateral, ramifying diverticula ; cuticular cilia fine,
distributed in even longitudinal rows ; contractile vesicles numerous ; endo-
plast ovate or band-like, subcentral. HAB. — Bog water.

The possession by this species of a complex and profusely ramifying cesopha:
geal canal, as first reported by Ehrenberg, and since maintained by Lieberkuhn and
Claparede and Lachmann, is not endorsed in this volume. In examples obtained
in bog water from Dartmoor, Devonshire, in August 1879, and examined by the
present author, the suspicion hitherto maintained that the endoplasmic substance
would be found to be highly vacuolate, somewhat as in Loxodes rostrum, and thus
lend a branched, intestine-like appearance to the intervening granular sarcode, was

' Histoire des Zoophytes Infusoires,' pi. vii. fig. 15, 1854.

GENUS A MPHILEP TUS. 523

entirely confirmed. The oral aperture, situated at the base of the anterior snout-like
prolongation, is followed by a short, conical, longitudinally plicate pharynx, as in
various specjes of Amphileptus, and there the oral system terminates. The more
granular or solid endoplasmic layer is at the same time usually developed more
conspicuously in a straight axial line backwards from the termination of the
pharynx, and receives all food-matters that pass through the oral aperture. Thus
physiologically, though not morphologically, it performs the part of an alimentary
tract. More slender ramifying diverticula from the main axial trunk are given off
at frequent but irregular intervals, their ultimate twigs spreading out upon and
anastomosing with the inner layer of the cortex. The closest resemblance to
this special modification of internal structure is encountered in the Flagellate
genus Noctiluca. In Loxodes there is no such distinct radiating disposition of the
internal endoplasm, this element being simply honeycombed by the intercalation
of irregularly developed ovate or subspheroidal lacunae. The number of contractile
vesicles possessed by this animalcule, while approached by Amphileptus gigas, is
surpassed only by the Prorodon margaritifera previously described ; they are very
minute, spheroidal, distributed throughout the peripheral region of the body, and
contract quite independently. On an average, it was estimated that as many
as fifty of these vacuoles were possessed by each single animalcule. Excepting for
the highly differentiated internal structure of the present type, it may be said to
accord in all essential points with the representatives of the genus Amphileptus
next described.

Supplementary Species.

The Trachdius trichopho^a of Ehrenberg, a"hd also the more recently recorded
Trachefais dendrophilus of the same authority, are Flagellate types referable to the
genus Astasia.

GENUS II. AMPHILEPTUS, Ehrenberg.

Animalcules highly elastic, ovate or elongate, usually more or less
flattened or compressed, the anterior region produced in the ferm of a trunk-
like appendage, at the base of which the oral aperture is situated ; cuticular
surface entirely and finely ciliate ; a comb- or mane-like row of longer cilia
often present on the inferior border of the trunk-like prolongation ; anal
aperture postero-terminal or subterminal ; contractile vesicles single or
multiple, trichocysts frequently present. Mostly inhabiting fresh water.

A signal service has been rendered by Claparede and Lachmann by their
amalgamation, under the generic title of Amphileptus, of the various forms originally
distributed by Ehrenberg and Dujardin among the separate genera Amphileptus,
Dileptus, and Trachelius, all of these, with the exception of Trachelius ovum, pre-
senting no features sufficiently distinctive for separate generic recognition. Almost
all the animalcules referable to this generic group are of large size, and are easily
recognized by the presence of the anterior trunk-like prolongation. This appendage
is completely under the control of its owner, being thrust hither and thither as the
creature progresses through the water, or carried stiffly in an arched, neck-like
manner. As seen under the last-named conditions, their appearance is so forcibly
suggestive of that of various long-necked aquatic birds as to have won for them the
several specific titles of Amphileptus eygnus, anas, and anaticula. From the long-
necked TracJielocerccz, with which they are most liable to be confounded, the repre-
sentatives of the genus Atnphilepttis may be readily distinguished by the position of
the mouth, which is at the base instead of at the apex of the trunk-like appendage.
Although normally of a more or less flattened form, these animalcules frequently
become distorted through the inception of food, assuming under such conditions
a cylindrical or almost spheroidal contour.

E 2

524 ORDER HOLOTRICHA.

Amphileptus gigas, C. & L. PL. XXVII. FIG. 68.

Body elongate-lanceolate, compressed or subcylindrical, attenuate pos-
teriorly ; the anterior trunk-like appendage equalling from one-fifth to one-
half or even the total length of the entire body, its inferior surface bearing
cilia of larger size, and enclosing throughout an even row of trichocysts ;
cuticular surface striate longitudinally ; pharynx conical, longitudinally
plicate ; contractile vesicles numerous, spherical, distributed throughout the
body-sarcode, frequently in a distinct row along the dorsal border ; endo-
plast band-like, S-shaped. Length 1-25" to 1-16." HAB. — Fresh water.

This species, which was found in tolerable abundance by Claparede and Lach-
mann in the neighbourhood of Berlin, represents one of the largest known infusorial
forms ; the number of contractile vesicles possessed by a single animalcule, as
recorded by these authorities, approaches that of Trachdius ovum and Prorodon
margaritifer, previously described, many being met with even in the anterior trunk-
like process. Wrzesniowski * has recently proposed to distinguish the two extreme
short and thick, and slender varieties of this animalcule, as encountered by himself
respectively at Grogec and Warsaw, by the subspecific names of Dileptus (Amphi-
leptus) gigas grojecensis and D. (Amph?) gigas varsaviensis. In the former of these the
proboscis never exceeds one-half of the length of the body proper, while in the second
and more attenuate form (see PI. XXVII. Fig. 68) this organ equals or even surpasses
the body in length. It was further observed by this authority that the short infundi-
bulate pharynx in the first-named variety was distinctly plicate, while in the second one
it was perfectly smooth. In no instance, even with the assistance of various reagents,
was Wrzesniowski successful in demonstrating the existence of a nucleus or endo-
plast in the numerous examples that fell under his observation ; the characters of
this structure, as given in the foregoing diagnosis, being derived from Claparede
and Lachmann's description. Wrzesniowski, on the other hand, records an instance
of multiplication by fission which was effected centrally in an oblique direction.
The habits of Amphileptus gigas, as attested to by the same observer, are essenti-
ally predatory; living food only is appreciated, and consists chiefly of other
Infusoria, such as Stylonychia histrio and S. pustulata, and various Rotiferae. These
are seized and at once transferred to the oral aperture with the assistance of the pro-
boscis, as the animalcule pursues its way through the water. Its powers of natation
are highly developed and unceasingly employed, locomotion consisting chiefly of
swift progression in a straightforward direction, accompanied by rotation of the
body on its long axis, the proboscis meanwhile being thrust around in a tentative
manner in search of prey. As figured by Wrzesniowski, the contractile vesicles .
are by no means so numerous as reported by Claparede and Lachmann, numbering
at the outside less than twenty, the greater portion of which are distributed in an
even row from one extremity to the other of the dorsal border.

Amphileptus cygrms, C. & L.

Body lanceolate, compressed ; the trunk-like prolongation flattened, equal
to the body in length, bearing cilia of slightly larger size on its inferior
surface ; posterior extremity of body attenuately pointed ; contractile vesicle
single, spherical, of large size, situated near the base of the proboscis.
Length of body, including the trunk, 1-60". HAB. — Pond water.

Amphileptus anas, Mull. sp.

Body elongate, subcylindrical, attenuate posteriorly ; trunk-like process
equal to one-half of the length of the entire body, thick and obtuse ; con-
* "Infusorien von Warschau," 'Zeit. Wiss. Zool.,' Bd. xx., 1870.

GENUS AMPHILEPTUS. 525

tractile vesicle single, spherical, situated near the posterior extremity ;
endoplasts two in number, round or ovate ; cuticular cilia disposed in even
longitudinal lines. Length of body 1-280" to 1-120".
HAB. — Pond water and infusions.

This species corresponds with the Trachelius anas of Ehrenberg, and with the
Trichoda anas and T. index of O. F. Muller. Through the inception of vegetable
food-particles it is frequently coloured bright green, examples so tinted representing,
probably, the type upon which Ehrenberg conferred the title of Amphileptus viridis,

Amphileptus vorax, Ehr. sp.

Body elongate-pyriform or clavate, rounded posteriorly ; the anterior
trunk-like portion thick and obtuse, not equalling one-half of the body in
length, flexible and curved in various directions ; oral aperture situated
towards the centre of the body, and at some little distance from the base of
the proboscis ; endoplast single, ovate. Length of body 1-120".

HAB. — Pond water, among Conferva.

This species is referred by Ehrenberg to the genus Trachelius.

Amphileptus moniliger, Ehr.

Body elongate-ovate, rounded posteriorly ; trunk-like process short ;
endoplast ribbon-like or moniliform. Length of body 1-96" to 1-72".
HAB. — Fresh water, amongst Lemncs.

Amphileptus anser, Ehr. PL. XXVII. FIGS. 39 AND 40.

Body elongate-lanceolate, pointed posteriorly ; trunk-like process equal-
ling the body in length; contractile vesicle single, spherical, posteriorly
situated ; endoplasts ovate, two in number. Length of body 1-120".

HAB. — Fresh water, among decaying vegetation.

According to Claparede and Lachmann, the pharynx of this animalcule presents
a longitudinally striate aspect, as in Amphileptus gigas. Although it was left
undetermined by these authorities whether these apparent striations were due to
membranous plications or to the presence of separate rod-like indurations, as in the
genus Prorodon and CMlodon, there appears to be but little doubt that the former of
these two premises may be accepted as the correct one.

Amphileptus margaritifer, Ehr.

Body elongate-fusiform, trunk-like process slender, equalling the body
in length ; contractile vesicles numerous, usually disposed in a necklace-like
manner along the dorsal border, sometimes a few others scattered irregu-
larly throughout the remaining portions of the body ; cuticular cilia fine and
inconspicuous. Length 1-72". HAB. — Fresh water.

Although the numerous contractile vesicles of this species were not recognized
as such by Ehrenberg, but are figured and described rather as accessory vacuoles
possessing some digestive function, their existence and true nature, as above
intimated, has been fully confirmed by the investigations of Claparede and
Lachmann.

526 ORDER HOLOTRICHA.

Amphileptus meleagris, Ehr. sp. PL. XXVII. FIGS. 45 AND 46.

Body lanceolate, compressed ; trunk-like process short and thick, scarcely
prominent ; oral aperture situated towards the centre of the body ; con-
tractile vesicles numerous, including a row of ten or twelve arranged along
the dorsal border ; endoplasts two in number, centrally located. Length
of body 1-96" to 1-60". HAB. — Fresh water.

This species is identical with the Trachelius meleagris of Ehrenberg, but not
with the Amphileptus meleagris of the same authority, this latter form being referable
to the genus Loxophyllum. An interesting phenomenon connected with the life-
history of this animalcule is recorded by Claparede and Lachmann. By various
previous investigators its occurrence, in association with cyst-like bodies attached
to the extremities of the branches of Epistylis plicatilis and other Vorticellidae, had
been noted, and by some of these, including notably D' Udekem, it was supposed that
the ciliated Amphileptus was a transitional condition of the Peritrichous type. The
Genevan authorities quoted have demonstrated, however, that the Amphileptus repairs
to the Epistylis colony for the express purpose of satisfying its hunger, and having
detached, swallowed, and digested a selected victim, fixes itself to and becomes
encysted at the extremity of the vacant stem. From this encystment the animalcule,
after a short interval of repose, makes its exit, sometimes in the simple condition
under which it entered, but more often in an augmented form, through its having
divided by segmentation within the cyst into two or four portions, each of which,
while of smaller calibre, corresponds entirely in form and structure with the original
single zooid. This interesting observation of Claparede and Lachmann has been
confirmed by various recent observers. An instance of an example attacking and
devouring a simple Vorticella, and then developing its characteristic cyst upon the
extremity of the semi-retracted and spirally curved pedicle of its victim, has been
noted by the present author. A Rhizopodal type, Vampyrella gomphonematis,
has been lately shown by Professor Haeckel to devour in a somewhat identical
fashion the cell-contents of the frustules of a species of Gomphonema, and upon
the branching pedicle of which diatom it afterwards affixes itself and becomes
encysted.

Amphileptus longicollis, Ehr.

Body dilated and rounded posteriorly, attenuate and trunk-like ante-
riorly ; the oral aperture situated nearer to the posterior than to the
anterior extremity of the body ; a conspicuous border of larger cilia de-
veloped on the lower surface of the trunk-like portion ; contractile vesicles
numerous, consisting of nine or ten vacuoles arranged in a line along the
dorsal border. Length of body 1-120" to 1-96".

HAB. — Pond water, amongst Conferva.

Amphileptus anaticula, C. & L.

Body pyriform, widest and subspherical posteriorly, tapering towards
the anterior extremity ; the trunk-like process attenuate, equal to one-third
of the length of the entire body, covered with longer cilia than those of the
general surface ; contractile vesicle single, postero-terminal ; endoplast single,
rounded. Length 1-570" to 1-280".

HAB. — Fresh water, among Confervas.

Except when feeding, the oral aperture of this species appears only as a
small depression at the base of the attenuate proboscis ; but in its elasticity and

GENUS LOXOPHYLL UM. 527

capacity to engulf organisms of considerable size it surpasses the ordinary repre-
sentatives of the genus. Among the figures given by Claparede and Lachmann
an example is delineated that has thus devoured a Peridinium whose diameter was
nearly equal to its own previous to the ingestion of its prey.

Amphileptus gutta, Cohn.

Body elongate-pyriform, rounded and widest posteriorly ; the anterior
extremity pointed, uncinate, curved towards the ventral aspect ; the dorsal
margin convex, the ventral one concave ; oral aperture situated on the
ventral surface at a distance of about one-third of the length of the body
from the anterior extremity ; pharynx taking the form of a smooth, conical,
corneous tube ; cuticular surface striate longitudinally, densely clothed
with short, fine, even cilia, no differentiation apparently exhibited by those
clothing the anterior or oral regions; contractile vesicle single, postero-
terminal ; endoplasm enclosing numerous large, spherical water-vacuoles ;
numerous refringent, nucleus-like corpuscles scattered throughout the
cortical layer ; movements constant in a forward direction, rotating on its
long axis. Length 1-200". HAB. — Salt water.

In general contour this species would appear to closely resemble Ehrenberg's
Trathelius (Amphileptus) vorax.

Amphileptus sphagni, Ehr.

Body depressed, linear-lanceolate, the rostrum or trunk-like portion cari-
nate, truncate, one-quarter the length of the body ; posterior extremity tail-
like, acutely pointed, the median region of the body coloured green, with
enclosed spheroidal corpuscles, elsewhere transparent ; cuticular cilia form-
ing spiral series. Length 1-576" to 1-144".

HAB. — Bog water, amongst Sphagnum, near Berlin.

This species, imperfectly described by Ehrenberg under the above title,* is
possibly referable to one of the other several genera into which his generic group
Amphileptus has been more recently divided.

Supplementary Species.

Among the species that must be referred with some degree of doubt to the
genus Amphileptus, and which are not sufficiently well characterized for exact
identification, are the Dileptus granulosus, Acineria incurvata et acuta, and the
Trachclius falx of Dujardin, and also the Amphileptus papillosus of Ehrenberg.
The Amphileptus fasdola of this last authority, referred by Claparede and Lachmann
to the genus Loxophyllum, will be found under the generic heading Litonotus.

GENUS III. LOXOPHYLLUM, Dujardin.

Animalcules free-swimming, flattened and leaf-like, flexible, finely and
entirely ciliate ; the anterior extremity usually more attenuate and elastic ;
oral aperture opening on the ventral border, the anal aperture situated
close to the posterior extremity; contractile vesicle single or multiple,

* 'Bericht Akad. Berlin,' 1853.

528 ORDER HOLO TRICHA .

frequently complex through the addition of lateral diverticula; tricho-
cysts usually present.

The animalcules of this genus most nearly resemble those of Amphileptus, but
are much more flattened in shape, while the anterior extremity, though usually more
flexible and attenuate, is not developed so as to form a separate trunk or proboscis.
As instituted by Dujardin * the genus Loxophyllum included only the Amphilept^ls
meleagris of Ehrenberg, his diagnosis as constructed thereon including such forms
only in which the margins of the leaf-like body are sinuous or undulate, and the
cuticular cilia distributed in widely separated parallel rows. As shown, however, by
Claparede and Lachmann, these last-named characters have merely a specific value.
In common with the other representatives of the Tracheliidce the members of the genus
Loxophyllum are apt to become distended and inflated, through the inception of
food-particles, though at the same time not to such an extent as to completely dis-
guise their normal lamellate contour, a thin flattened marginal border at all times
remaining conspicuous. The Loxophyllum fasciola of Claparede and Lachmann,
identical with the Amphileptus fasciola of Ehrenberg and the Dileptus folium of
Dujardin, has been removed, in accordance with the recent discoveries of
Wrzesniowski, to the Hypotrichous genus Litonotus.

Loxophyllum meleagris, Ehr. sp. PL. XXVII. FIG. 52.

Body leaf-like, obliquely lanceolate, highly elastic, about three times as
long as broad, the anterior extremity pointed and curved towards the
dorsal aspect ; the dorsal border crenulate ; oral aperture situated on the
ventral side close to the anterior extremity ; contractile vesicle spherical,
postero-terminal, communicating with a canal-like prolongation, that extends
along the dorsal margin nearly to the anterior extremity of the body ;
cuticular cilia disposed in distinct longitudinal parallel rows ; endoplast
single, ribbon-like, or forming a moniliform chain of bead-like nodules ;
trichocysts abundantly developed, usually forming a continuous series along
the ventral border. Length 1-75". HAB. — Pond water.

This species, which is identical with the Amphileptus meleagris of Ehrenberg, is
the type upon which Dujardin instituted the present genus. The Trachelius
meleagris of the first authority is, as already mentioned, referable to the genus
Amphileptus. According to the recent researches of Wrzesniowski,f considerable
differences exist between animalcules referable to this type obtained from separate
localities. Thus, while at Warsaw the examples gathered conformed entirely with
the diagnosis above given, those at Grogec were of extremely attenuate proportions,
no less than seven or eight times as long as broad, and exhibited a further important
difference in the number and arrangement of the trichocysts. The latter structures
formed not only a continuous row throughout the ventral border but were also present
in bundles on the dorsal one ; these bundles, again, were not distributed in regular
order, but one occupied a position corresponding with the projecting portion of each
marginal undulation. This so-called variety, seeming to merit separate specific dis-
tinction, the present author is disposed, in honour of its discoverer, to provisionally
confer upon it the title of Loxophyllum Wrzesniowskii. The character of the con-
tractile vesicle of L. meleagris, with its diverging canals, and also that of the endoplast,
is well illustrated in Wrzesniowski's excellent figures of this species. The breaking
up of the primary band-like contour of this latter structure results in the production
of a number of fragments of variable size which, while apparently scattered at random

* ' Histoire des Zoophytes Infusoires,' Paris, 1854.

t ' Archiv fiir Mikroskopische Anatomic,' Bd. v., 1869.

GENUS L OXOPHYLL UM. 529

through the body-substance, remain, as in Loxodes rostrum, connected with one
another through the medium of a hyaline cord-like filament or funiculus. The
employment of reagents such as iodine and carmine tincture is requisite for the
satisfactory demonstration of this phenomenon. The peculiar canal-like modification
of the contractile vesicle, while occurring frequently among the higher Heterotricha,
has not, with the exception of Haptophrya, been yet reported of any other Holo-
trichous form. It evidently represents a more specialized development, through
coalescence, of the dorsal row of spherical vesicles common to many species of the
preceding genus, and shared likewise by Loxophyllum setigerum.

Loxophyllum armatum, C. & L. PL. XXVII. FIG. 53.

Body leaf-like, semicircular, having no attenuate anterior portion, the
posterior termination revolute ; oral aperture situated at a distance of one-
third of the entire length from the anterior extremity, the dorsal border
entire, not undulate ; the ventral margin arcuate, containing abundant
trichocysts ; cuticular surface finely ciliate, the cilia disposed in even longi-
tudinal rows ; contractile vesicle spherical, posteriorly located, sometimes
exhibiting a stellate outline, or dividing at the time of systole into two
segments. Increasing by transverse fission. Length 1-150".

HAB. — Bog water : Berlin (C. & L.).

With the aid of the large trichocysts which arm the ventral border, this species
has been observed by Claparede and Lachmann to paralyze and capture other
smaller animalcules.

Loxophyllum lamella, Ehr. sp>

|

Body elongate, linear-lanceolate, attenuate anteriorly, rounded poste-
riorly ; the dorsal margin not crenulate ; contractile vesicle single, postero-
terminal ; endoplast double ; no trichocysts. Length 1-200".
HAB. — Fresh water.

This species is identified by Claparede and Lachmann with the Trachelius
lamella of Ehrenberg, but not with the many forms similarly named by Dujardin, and
which, together with the Trachelius stricta of the same writer, they consider, while
possibly belonging to the genus Loxophyllum, as too insufficiently characterized for
identification.

Loxophyllum rostratum, Cohn.

Body leaf-like, highly elastic and retractile ; the ventral surface flattened,
the centre of the dorsal one convex, surrounded by a thin, transparent, lami-
nate border ; rounded posteriorly, developed anteriorly into a flexible, pointed,
dorsally reflected, uncinate prolongation or rostrum ; cuticular surface deli-
cately furrowed longitudinally, clothed throughout with fine cilia, those in
the region of the uncinate anterior prolongation slightly longer than the
others ; the centre of the dorsal border conspicuously undulate, a row of
trichocysts extending from this undulated border half-way to the apical
extremity of the rostrum ; one, two, or three contractile vesicles posteriorly
situated ; endoplast double, centrally located ; a row of refringent bodies
frequently present near the base of the dorsal border. Length 1-144".

530 ORDER HOLOTRICHA.

HAB. — Salt water ; movements smooth and even, or rotating on its long
axis.

The general contour of this species, as recently figured and described by Cohn,*
closely resembles that of the fresh- water type Loxophyllum meleagris.

Loxophyllum setigerum, Quenn.

Body flattened, irregularly rhomboidal, widest centrally, most attenuate
anteriorly ; the dorsal border nearly straight, neither undulate nor bearing
trichocysts, the ventral one strongly and gibbously arcuate, three or four
seta-like structures projecting irregularly from its posterior half; contractile
vesicles numerous, forming a continuous row down the dorsal margin.
Endoplast moniliform. Length 1-150". HAB. — Saltwater.

Fam, VIII. ICHTHYOPHTHIRIID.2E, S.K.

Animalcules adherent, more or less ovate, ciliate throughout, oral cilia
of larger size than those of the general cuticular surface, oral region
adhesive, acetabuliform.

GENUS I. ICHTHYOPHTHIRIUS, Fouquet.

Animalcules more or less ovate, highly elastic, entirely ciliate, oral
orifice terminal, situated in the centre of an adherent, discoidal, acetabuli-
form area, the inner margin of which bears numerous inwardly projecting,
setose cilia. Endoplast and contractile vesicles conspicuously developed.
Occurring as parasites on the epidermal surface of various fishes.

Ichthyophthirius multifiliis, Fouquet. PL. XXXII. FIGS. 1-8.

Body subglobose or ovate, flexible and elastic ; cuticular surface finely
and evenly ciliate throughout, the cilia arranged in fine, intercrossing,
obliquely parallel rows ; an aspect as of trichocysts underlying the entire
cuticle apparent in the younger zooids ; adhesive suctorial disc apical,
minute, and cup-like, its inner surface bearing about twenty, inwardly
radiating, larger, setose cilia ; contractile vesicles numerous, minute, scat-
tered throughout the cortical layer ; endoplast band-like, curved ; endoplasm
densely granulate. Length 1-150".

HAB. — Parasitic on the common Trout, Salmo trutta, and other soft-
skinned fresh-water fish.

The occurrence of this animalcule as a parasite of various fresh-water fish, in
eluding more notably the Loach, Cobitis fossilis, was notified by MM. F. Hilgendorf
and A. Paulicki of Hamburg, in the ' Centralblatt ' for January 1869. The account
then given of it was, however, very incomplete, and the animalcule was pro-
visionally referred to Ehrenberg's genus Pantotricha. The first full description of this
type, accompanied by the bestowal upon it of the distinctive title above given, did
not appear until some years later, when M. Fouquet figured and described it at
length in the ' Archives de Zoologie Expe'rimentale,' torn. v. pp. 159-165, for the year
1876. According to thfs authority, the species had then for the last ten years proved
very destructive to the young trout raised in the artificial basins of the fish-houses

* " Neue Infusorien im Seeaquarium, " ' Zeit. Wiss. Zool.,' Bd. xvi., 1866.

GENUS ICHTHYOPHTHIRIUS. 5 3 1

of the College de France, the inflammation of the epidermal tissues induced by their
presence in large quantities proving fatal within a very short interval. In a
fish affected by these parasites, prominent, rounded, milk-white spots are to be
observed on the eyes, fins, branchiae, or general cuticular surface, in depressions
in which, when examined with the aid of the microscope, the animalcules will
be found lodged, sometimes singly and in other instances in great numbers. Each
animalcule is fixed to the bottom of the depression by the apical adhesive disc, and
rotates backwards and forwards from right to left and left to right upon its longitu-
dinal axis, by the movement apparently of the cilia of the cuticular surface, and thus
bores it way deeper into the skin of its victim. The reproductive phenomena of this
species, as recorded by Fouquet, are highly interesting. Arriving at maturity, the
animalcules become detached from their host, and falling to the bottom of the water,
encyst and become divided by repeated segmentation, accompanied by a like division
of the endoplast, into a morula-like mass consisting of at least a thousand ovate
ciliated bodies which ultimately escape from the ruptured cyst, and grow by degrees
to the parent form. This reproductive process occupies an interval of from forty to
fifty hours. At first, the young animalcules thus developed, PI. XXXII. Figs. 5 and 6,
are much more elongate than the parent zooids, and have no apical suctorial disc ;
the endoplast is likewise simply ovate, and accompanied by an endoplastule which
disappears a little later, while the contractile vesicle" is single and laterally developed.
The close correspondence of this form of multiplication with the sporular reproductive
process of the simpler Flagellata is eminently noteworthy. The two or three months
extending from the end of May till August are those in which the young trout are
most liable to be affected by the attacks of this Infusorium. The placing of frag-
ments of tiles or other substances against which the fish can rub themselves, and
thus get rid of their puny assailants, supplemented by the maintenance of the water
at ^a low temperature, are recommended as the best checks to their inroads.

Some uncertainty would seem to exist respecting the precise import of the
suctorial organ developed at the apical extremity of Ichthyophthirius. According to
Fouquet, this structure does not constitute a perfect oral apparatus, it consisting
merely of a circular opening, bordered by larger cilia, which leads into a small
cul-de-sac, and is not continued into the deeper substance of the body. Carmine
administered in a pulverized condition was not assimilated, a circumstance, correlated
with the structural peculiarities just cited, Fouquet considers sufficient to indicate
that the animalcule is strictly mouthless, and that the apical acetabuliform organ,
while possibly representing a degraded oral aperture, is subservient merely for the
purposes of adhesion. Viewed in this light, the animalcule is regarded as possessing
probable affinities with the Opalinidae, in which group, indeed, one genus, Hap-
tophrya, is distinguished by its possession of a somewhat analogous acetabuliform
organ. It is at the same time worthy of remark that the densely granular character
of the endoplasm of Ichthyophthirius, as indicated by Fouquet's figures — certain of
which are further distinguished by the incorporation of so-called pigmentary cor-
puscles— is highly suggestive of the presence of extraneously derived, solid nutriment
To this it may be added that all mouthless organisms, in the strict sense of the term,
are, so far as known, essentially endoparasites, subsisting by absorption on the
nutrient juices provided within the intestinal viscera of the hosts they respectively
inhabit. Under these circumstances it has been considered advisable to at least
provisionally retain the present highly interesting type among the ordinary Stoma-
tocle Holotrichous Ciliata, apportioning it there, with reference to its remarkable
oral or pseud-oral system, an independent family distinction.

Fam. IX. OPHRYOGLENID-aE, S. K.

Animalcules free-swimming, ciliate throughout, oral and cuticular cilia
uniform in size ; oral aperture terminal, lateral or ventral, situated at the
bottom of a distinct oral fossa or vcstibulum, within which is enclosed a
vibratilc flap or membrane.

532 ORDER HOLOTRICHA.

With the Ophryoglenidse commences an important and extensive series of the
Holotrichous Ciliata, distinguished in all instances by the possession of a more or
less extensively developed membraniform appendage, in addition to the usual com-
plement of cuticular and oral cilia. Where such a supplementary membrane is
extensively developed, as in the genera Lembus and Proboscella, there can be but little
doubt that we have foreshadowed the system of conspicuously larger adoral cilia
characteristic of the ordinary Heterotricha, and which system not unfrequently
originates as a similar simple band-like membrane. A partial recognition of the
natural affinity of the membrane-bearing Holotricha is recorded by Stein in his
classification scheme, reproduced at p. 210 of vol. i. He at the same times places
the genus_Pafiofl/irys among the ordinary Paramsecina, while all the rest are collected
together in the single family group of the Cinetrochilina, without regard to the
essentially distinct plans upon which, in so many of these genera, the membraniform
appendage is constructed.

GENUS I. OPHRYOGLENA, Ehrenberg.

Animalcules free-swimming, persistent in shape, more or less ovate and
depressed, having a convex dorsal and flattened ventral surface, the oral
fossa opening on the ventral aspect at a little distance from the anterior
extremity, enclosing an ovate, vibratile, flap-like membrane ; anal aperture
subterminal ; general surface of the body entirely and evenly ciliate ; no
larger adoral cilia ; cortical layer usually containing thickly set trichocysts ;
endoplast and contractile vesicle conspicuous. Inhabiting pond and bog
water.

An additional and leading distinction of the genus Ophryoglena, as instituted by
Ehrenberg, is the presence, near the anterior extremity of the body, of a coloured
eye-like pigment-spot. More recent investigation has, however, shown that this
character is altogether subordinate, such a pigment-spot not being constant, either
with respect to its presence or location, even among zooids of the same species.

Ophryoglena acuminata, Ehr.

Body ovate, flattened, pointed and acuminate posteriorly, little over one
and a half times as long as broad ; colour brown ; oral fossa extending back-
wards to about the centre of the body ; a scarlet pigment-spot usually
present near the anterior extremity; contractile vesicle single, spherical,
situated in the median line towards the anterior extremity; endoplast
rounded, located a short distance behind the contractile vesicle. Length
1-180". HAB. — Bog water.

The habits of this animalcule are essentially phytophagous ; the diatom Navicula
gracilis, which, according to Ehrenberg, is an especially favourite food, being often
found in great numbers within the body-substance.

Ophryoglena atra, Ehr. PL. XXVI. FIGS. 63 AND 64.

Body ovoid, flattened, pointed posteriorly, nearly twice as long as
broad ; colour very dark and opaque, usually with a bluish pigment-spot
near the anterior extremity ; oral fossa broad and deep, extending back-
wards to nearly one-half of the length of the entire body, the membranous
flap occupying the posterior half of its cavity ; contractile vesicle single

GENUS PANOPHRYS. 533

situated a little in advance of the median line, presenting at diastole a
stellate outline ; the cortical layer containing abundant closely set tricho-
cysts. Length 1-180". HAB. — Bog water.

Ophryoglena oblonga, Stein.

Body ovate, rounded posteriorly ; oral fossa elliptical, straight, set more
forwards than in Q. atra ; endoplast spheroidal, no endoplastule ; eye-like
pigment-spot usually present. HAB. — Fresh water.

Ophryoglena caeca, Stein.

Form, and position of oral aperture coinciding with C. oblonga, but
larger and thicker ; endoplast oval, having an attached endoplastule ; no
eye-like pigment-spot. HAB. — Fresh water.

This and the preceding form are briefly characterized by Stein as above in
the ' Sitzungsberichte der konigl. Bohmischen Gesellschaft der Wissenschaften ' for
December 1860.

Ophryoglena Wrzesniowskii, Mereschk. sp.

Body scarcely twice as long as broad, transparent, somewhat variable
in form, more or less evenly ovate, rounded at each extiemity, the posterior
end usually slightly the wider; oral fossa situated a little to the right
of the median line at a short distance from the anterior extremity, en-
closing apparently two opposed membranous flaps ; cuticular surface
longitudinally striate, finely ciliate throughout ; the cortical layer com-
pletely filled with large, closely approximated, rod-like trichocysts ; con-
tractile vesicle single, located close behind the oral fossa; endoplast
spherical, subcentral. Length 1-175".

HAB. — Fresh water : river Dwina and Lake Onega (Mereschkowsky).

This species is figured and described by Mereschkowsky, in his account of the
Infusoria of Northern Russia,* as a species of Glaucoma; from his figure and
diagnosis given, it is however evident that the animalcule is a true Ophryoglena,
differing but slightly from the common forms O. atra and O. acuminata. The bilabiate
aspect of the oral membrane, upon which alone its claim for admission to the first-
named genus is based, has been frequently noted by the author in connection with
the last-named types.

Supplementary Species.

The Ophryoglena flavicans of Ehrenberg, and O. citreum of Claparede and Lach-
mann, characterized by the presence of a fringe of larger cilia round the oral
aperture, are here referred to the genus Panophrys of Dujardin. The Ophryoglena
griseo-virens of Perty, is apparently a variety only of O. atra.

GENUS II. PANOPHRYS, Dujardin.

Animalcules ovoid, more or less persistent in shape; oral aperture
situated at the bottom of a pocket-like fossa, which originates on the

* ' Archiv f. Mikrosopische Anatomic,' Bd. xvi., 1878.

534 ORDER HOLOTRICHA.

ventral surface near the anterior extremity, its outer margin bordered by a
spiral circle of cilia of larger size than those which cover the general surface
of the body ; the upper portion of the posterior extremity of the oral
fossa bearing an undulating membrane. A coloured eye-like pigment-spot
often present near the anterior extremity ; the cortical layer frequently
containing trichocysts.

The conspicuous fringe of larger adoral cilia serves to distinguish the representa-
tives of this genus from those of Ophryoglena, with which they otherwise closely
correspond ; the spiral disposition of these adoral cilia separates it in a distinct
manner from the succeeding genus Cydotricha.

Panophrys flavicans, Ehr. sp. PL. XXVI. FIGS. 65 AND 66.

Body elongate-ovoid, convex above, flattened beneath, rounded
anteriorly, pointed at the posterior extremity, about twice as long as broad ;
colour yellow; entrance to oral fossa subterminal, crescentic, associated
with a spirally winding axloral fringe of larger cilia, its cavity capacious,
extending back to within a short distance of the median line ; an
anterior red eye-like pigment-spot usually present; the cortical layer en-
closing numerous evenly developed trichocysts ; endoplast oval. Length
1-144". HAB. — Bog water.

This species, which constitutes the type-form of the genus Panophrys of Dujardin
and Stein, is identical with the Ophryoglena flavicans of Ehrenberg.

Panophrys flava, Ehr. sp.

Body normally pear-shaped, flattened, narrowest posteriorly, little over
twice as long as broad, flexible and somewhat changeable in form ; colour
yellow ; adoral cilia spirally arranged ; no eye-like pigment-spot nor tricho-
cysts. Length 1-96". HAB. — Fresh water.

While most nearly resembling Panophrys flavicans, Claparede and Lachmann
remarks that it is readily distinguished from that species by its non-persistent shape,
and by the absence of a pigment-spot and trichocysts. It was first described by
Ehrenberg under the title of Bursaria flava, but subsequently transferred to the
present genus by Dujardin.

Panophrys chrysalis, Duj.

Body ovoid or oblong, depressed, rounded at the two extremities, twice
as long as broad, margin of oral fossa projecting ; cortical layer apparently
armed with trichocysts. Length of body 1-138". HAB. — Saltwater.

Supplementary Species.

The species described by Ehrenberg under the two titles of Bursaria leucas and
Bursaria vernalis, referred to the genus Panophrys by Dujardin, has been selected by
Stein as the type of the new genus Cyrtostomum, previously described. Other forms,
included in the genus Panophrys by Dujardin and Perty under the titles of P. rubra,
farcta, conspicua, sordida, zonalis, griseola, and paramecioides, are characterized too
insufficiently for present identification.

GENUS CYCLOTRICHA—TRICHODA. 535

GENUS III. CYCLOTRICHA, S. K.

Animalcules free-swimming, more or less ovate, persistent in shape,
entirely ciliate ; oral aperture ventral, situated at the bottom of a pocket-
shaped oral fossa, the entrance to which is surrounded by a simple and
entire circlet of cilia, larger than those of the general cuticular surface,
the further confines of oral fossa supporting a watchglass-shaped undulating
membrane.

This genus is herewith established for the reception of the Ophryoglena citreum
of Claparede and Lachmann. From Ophryoglena and Meniscostomum it is to be
distinguished by the larger calibre of the oral cilia, in comparison with those of the
general surface ; their simply circular disposition serves at the same time to separate
it from Panophrys.

Cyclotricha citrea, C. & L. sp. PL. XXVI. FIGS. 67 AND 68.

Body lemon-shaped, pointed at each extremity, about one and a quarter
times as long as broad ; the entrance to the oral fossa situated at a distance
of one-quarter of the total length from the anterior extremity of the body ;
the adoral cilia forming a simple circular fringe ; no pigment-spot or tricho-
cysts ; endoplast elongate, band-like ; contractile vesicle single, spherical,
located near the dorsal margin. Length of body 1-225".
- HAB. — Bog water.

GENUS IV. TRICHODA, Mullen

Animalcules free-swimming, elastic, but more or less persistent in shape,
ovate or pyriform ; oral aperture situated at the pointed and obliquely
truncate anterior extremity, approached by an ovate oral fossa, whose
inner wall gives attachment to a single, vibratile, flap-like membrane ;
cuticular surface finely ciliate throughout, a circlet of larger cilia sur-
rounding the entrance to the oral fossa. Especially abundant in putrid
infusions.

The animalcules of this genus, while corresponding closely in external contour
and habits with those of Enchelys, are to be distinguished from them by the presence
of the minute vibratile membrane that is enclosed within the oral fossa. Trichoda, in
common with Enchelys, was originally distinguished by Ehrenberg with reference to
the apparent absence of cilia throughout the general surface of the cuticle. Fine
body cilia are now known to exist in all the species.

Trichoda pura, Ehr. PL. XXVII. FIG. 47.

Body elongate-pyriform or clavate, slightly curved towards the ventral
aspect, about three times as long as broad, widest and rounded posteriorly,
tapering gradually towards the anterior extremity; oral fringe of cilia alone
conspicuous, those of the general cuticular surface very fine ; endoplast
spherical, subcentral ; contractile vesicle posteriorly located. Length
1-720".

536 ORDER HOLOTRICHA.

HAB. — Pond water and vegetable infusions in company with Cyclidium
glaucoma.

This species, in common with Enchelys farrimen, is one of the most abundant
Ciliate types developed in hay and other vegetable infusions, the attraction
there being the abundant harvest of monadiform animalcules upon which it in
like manner feeds voraciously. The cuticular surface in this animalcule is exceed-
ingly soft and flexible, permitting it to assume the most protean contortions as it
forces its way among the vegetable debris contained in the infusion. When swim-
ming freely in the water, it moves swiftly forwards or backwards in a straight line, or
progresses leisurely, mouth downwards, after the manner of an Enchelys.

Trichoda carnmm, Ehr. sp.

Body elliptical, slightly narrower anteriorly, rather over twice as long as
broad, the oblique oral fossa of considerable dimensions ; oral and cuticular
cilia conspicuous ; contractile vesicle single, postero-terminal ; endoplast
subcentral, spheroidal ; colour white. Length 1-430".

HAB. — Animal macerations, and water from dung-hills.

This species is identical with the Leucophrys carnium of Ehrenberg.

Trichoda pirum, Mull. sp.

Body pyriform, widest posteriorly, narrowest and pointed anteriorly,
twice as long as broad ; cuticular and oral cilia conspicuous, oral fossa not
so distinct as in T. carnium; colour white. Length 1-1250" to 1-400".

HAB. — Pond water, with Euplotes charon, and Polytoma uvella.

This animalcule is apparently identical with the form first described by Bory de
St. Vincent under the name of Enchelys pyriformis, and since referred by Ehrenberg
to the genus Leucophrys. It was originally figured by O. F. Miiller under the title
of Kolpoda pirum. It would seem highly probable, as already suggested by Dujardin,
that Ehrenberg's Trichoda carnium must be also accepted as a synonym of this
species.

Doubtful Species.

The four following species, referred by Ehrenberg to the genus Trichoda, are too
meagrely described for present identification. No evidence as to their possessing
vibratile oral membranes being recorded, they might with equal justice be referred
to the genus Enchelys.

Trichoda nasamomum, Ehr. — Body cylindrical, extremities equally obtuse ; mouth
large, elongated laterally. Length 1-288".

Trichoda ovata, Ehr. — Body ovate, turgid, attenuated anteriorly ; mouth small,
lateral. Length 1-480". HAB. — Egypt.

Trichoda (?) athiopica, Ehr. — Body oblong, attenuated posteriorly; under side
flat ; mouth large. Length 1-600".

Trichoda asiatica, Ehr. — Body oval, oblong, cylindrical, rounded at both ends ;
mouth small. Length 1-800".

The Trichoda angulata of Dujardin — thus defined : Body oblong, obliquely
angular, often containing one or more superficial vacuoles. Length 1-300".
Inhabiting water with decaying plants — is apparently, from the figure given, allied
to or identical with Colpoda cucullus.

GENUS V. LEMBADION, Perty.

Animalcules free-swimming, persistent in form, more or less ovate,
entirely ciliate; oral fossa terminal, capacious, its right side supporting

GENUS COLPIDIUM. 537

an ovate undulating membrane, its left one ciliatc ; the posterior extremity
of the body usually bearing supplementary setose cilia.

Lembadion bullinum, Perty. PL. XXVII. FIG. 54.

Body ovate, compressed, nearly twice as long as broad, slightly widest
posteriorly ; oral fossa capacious, extending through two-thirds of the entire
length of the body; two long hair-like setse projecting from the posterior
extremity ; endoplast spherical, posteriorly located ; contractile vesicle
single, situated near the centre of the right lateral border. Length 1-240"
to 1-192". HAB. — Marsh water.

This species was formerly referred, even by Stein, to the family of the Bursarina,
the undulating membrane which that authority has since demonstrated to exist
within the oral fossa being then regarded as a fringe of larger adoral cilia. For such
larger adoral cilia this membrane has likewise been mistaken by Claparede and
Lachmann, who have consequently placed it in their treatise next to the genus
Bursaria. These last-named investigators remark that under disturbing or uncon-
genial influences the animalcules of this species swim rapidly backwards, turning
upon their long axis, while, when seeking for food or moving at leisure, they
progress slowly forwards without any revolving action. Ernst Eberhard* represents
this type as bearing three postero-terminal setae.

Doubtful Species.

The Lembadion (?) duriusculum of Perty is a doubtful form, certainly not referable
to the genus under notice, and whose exact relationship cannot at present be decided.
Its diagnosis, as given by Perty, is as follows : Body persistent in form, elliptical,
colourless, with usually a keel or ridge along its upper surface ; the under surface
somewhat concave ; cilia very fine ; movements sluggish. Length 1-720" to 1-620".
HAB. — Fresh water.

GENUS VI. COLPIDIUM, Stein.

Animalcules free-swimming, entirely ciliate, persistent in form, more of
less kidney-shaped ; oral aperture inferior, subterminal, pharynx supporting
throughout its length an undulating membrane which projects exteriorly
in a tongue-like manner.

Colpidium cucullus, Schrank sp. PL. XXVII. FIG. 49.

Body kidney-shaped, narrower1 and curved towards the ventral aspect
anteriorly, two or three times as long as broad ; cuticular cilia distributed
in even longitudinal rows ; endoplasts two in number, rounded, subcentral ;
contractile vesicle located near the centre of the dorsal border. Length
1-500" to 1-250". HAB. — Fresh water and infusions.

This species was first figured and described by Schrank, 'Fauna Boica,' 1803,
under the title of Colpoda cucullus. It is identical with the Parameaum kolpoda of
Ehrenberg, and Claparede and Lachmann, and with the Kolpoda cucullus of Dujardin,
but not with the Colpoda cucullus of Ehrenberg, which is a more simple-formed
animalcule, having a conspicuous tuft of oral cilia but no vibratile membrane.

* ' Osterprogramm zu Coburg,' 1862.

VOL. II. F X/

/CV'o0 °< v

-*.•-»- >
LIBRARY

538 ORDER HOLOTRICHA.

Chilodon cucullulus, a second species, which also corresponds closely with this type
in its reniform external contour, is easily distinguished from it by the cylinder
of rod-like teeth with which the pharynx is armed, and by the unilateral dis-
tribution of its cilia. According to Ehrenberg, Colpidium cucullus sometimes pos-
sesses two closely approximated contractile vesicles, as well as a double endoplast.
It is one of the commonest forms developed in vegetable infusions.

GENUS VII. PLAGIOPYLA, Stein.

Animalcules free-swimming, persistent in shape, ovate or subcylindrical,
ciliate throughout ; oral fossa ventral, located slightly in advance of the
median line, sometimes approached by a transversely directed groove, its
inner border bearing a narrow, non-projecting, undulating membrane, fol-
lowed by a short tubular pharynx ; anal aperture postero-terminal ; the
cortical layer often enclosing trichocysts.

The enclosure of the undulating membrane within the oral fossa distinguishes this
generic type from Colpidium.

Plagiopyla nasuta, Stein. PL. XXVII. FIGS. 50 AND 51 (?).

Body subreniform, rounded at each extremity ; oral fossa pocket-
shaped, produced at right angles to the cuticular surface to the centre of
the body, enclosing an elongate, tongue-shaped, undulating membrane,
not followed by a distinct pharyngeal passage ; trichocysts conspicuous ;
endoplast elongate-oval, located in the right body-half behind the peri-
stome ; contractile vesicle postero-terminal ; anal aperture subterminal.
Length 1-240" to 1-190". HAB. — Fresh water.

This typical species of the genus Plagiopyla is described by Stein as somewhat
resembling Pleuronema chrysalis, but without the longer ventral cilia or extensile
membrane. The animalcule figured by Quennerstedt * under the title of Para-
mcecium cucullus, corresponds so nearly with Stein's diagnosis of the present species
that the Swedish authority's delineations are herewith reproduced as probably
representing the same type.

Plagiopyla (?) Garten, S. K. PL. XXVI. FIG. 69.

Body elliptical, cylindrical, equally rounded at the two extremities,
about twice as long as broad ; oral aperture situated nearly midway between
the centre and the anterior extremity of the body, enclosing a minute,
lunate, undulating membrane, followed posteriorly by a conically pointed
tubular pharynx ; the anal aperture lateral, situated on the same side as
the mouth, midway between the median line and the posterior extremity;
cuticular cilia short, disposed in even longitudinal rows ; contractile vesicle
lateral, subcentral, located on the opposite side to the oral and anal aspect ;
endoplast undetermined. Length 1-125".

HAB. — Fresh water : Bombay (H. J. C).

* 'Sveriges Infusoriefauna,' 1867.

GENUS MENISCOSTOMUM. 539

This species, figured and briefly described by Mr. H. J. Carter in his manuscript
notes under the title of Paramxcium ?, as also the form next described, would perhaps
be more rightly referred to the genus Ophryoglena, though in all essential details,
with the exception of the transverse groove-like approach to the oral aperture, it
would seem to conform with Stein's diagnosis. While no mention is made of the
lunate vibratile membrane within the oral fossa, its presence is clearly indicated in
Mr. Carter's sketch as here reproduced. The backward continuation of the
pharyngeal cleft beyond the attachment of the enclosed vibratile membrane, both in
this and the succeeding species, in addition to the smaller size and more ventral
location of the oral aperture, distinguishes them from the ordinary members of the
genus Ophryoglena.

Plagiopyla (P) fusca, Quenn. sp. PL. XXVI. FIG. 70.

Body persistent in shape, elliptical, evenly rounded at each extremity,
twice as long as broad ; cuticular surface delicately striate longitudinally,
finely ciliate throughout, the cortical layer enclosing closely set trichocysts ;
oral aperture opening a little in advance of the median line, enclosing
a conspicuous undulating membrane, followed by a short, backward directed,
tubular pharynx; contractile vesicles two in number, small, spheroidal,
one stationed in the anterior, and the other in the posterior third of the
body ; endoplast oval, subcentral. Length 1-200". HAB. — Salt water.

This animalcule is figured and described in connection with the above specific
name, by Quennerstedt * as a new form of Panophrys ; the non-existence, however,
of a fringe of larger cilia round the oral aperture necessitates its removal from that
genus, while the construction of the oral aperture and pharyngeal passage indicates
its close affinity with the type last described.

GENUS VIII. MENISCOSTOMUM, S. K.

Animalcules free-swimming, ovate, persistent in shape, entirely ciliate ;
oral fossa lateral, shallow, meniscoidal, enclosing a narrow, lunate, vibratile
membrane, no cilia of larger size round its outer border, and not followed
by a tubular pharynx ; contractile vesicles usually two in number.

This new generic appellation is here instituted for the reception of a single
Holotrichous type whose form and structure, while most closely approaching that of
the preceding genera Ophryoglena and Plagiopyla, differs from the former in the
simple cup-like contour of the oral fossa, and from the latter by the absence of
an accompanying tubular pharyngeal passage. The cup-like oral fossa, as seen in
profile, presents a very characteristic aspect, appearing under such conditions as
a clean-cut lunate notch in the antero-lateral border, as shown in the figure illustrative
of the single type described.

Meniscostoxnum stomioptycha, Eck. sp. PL. XXVII. FIG. 48.

Body obtusely ovate or elliptical, evenly rounded at both extremities,
about twice as long as broad ; oral fossa forming a shallow circular exca-
vation at a distance of one-third of the entire length of the body from the
anterior extremity, its inner border bearing a lunate vibratile membrane ;-
cuticular cilia even, forming dense longitudinal series ; contractile vesicles

* ' Sveriges Infusoriefauna,' 1869.

F 2

540 ORDER HOLOTRICHA.

two in number, of large size, assuming at full diastole a stellate contour,
situated in the same median line towards the anterior and posterior regions
of the body ; endoplast elongate-ovate, longitudinally disposed, located a
little to the rear of the oral fossa. Length 1-288" to 1-180".
HAB. — Fresh water.

This species was first figured and described by Eckhard * under the name of
Paramcecium stomioptycha, and has been referred to later on by Ehrenberg \ in
connection with the same title. Although the surface ciliation and character of the
contractile vesicles accord closely with those of certain Paramcecia, the oral
structure, as delineated in Eckhard's original drawing, herewith reproduced, is
essentially distinct.

GENUS IX. CHASMATOSTOMA, Engelmann.

Animalcules free-swimming, persistent in shape, ovate or kidney-shaped,
somewhat flattened ; cilia long, matted, equally distributed ; oral fossa
situated near the centre of the flattened ventral surface, enclosing a minute
undulating membrane.

While the contour of the body, the matted character of the cilia, and the position
of the oral fossa in this genus correspond closely with those of Conchophthirus , the
possession of a supplementary undulating membrane indicates its affinity with
Ophryoglena and Meniscostomum.

Chasmatostoma reniforme, Eng. PL. XXVI. FIG. 48.

Body kidney-shaped, about one and a half times as long as broad,
obtusely rounded at each extremity, the anterior one slightly the narrower,
the dorsal surface convex, the ventral one flattened ; oral fossa subcentral,
small, and of ovate contour ; undulating membrane attached to the right
inner side of the oral cavity ; cilia long, fine, and thickly set over the entire
cuticular surface, presenting a tufted or matted aspect ; contractile vesicle
postero-terminal, rosette-like during systole ; endoplast spherical, situated
in front of the contractile vesicle. Length 1-400".

HAB. — Fresh water, with Colpoda cucullus,

This species is figured and described by T. W. Engelmann in the ' Zeitschrift fur
Wissenschaftliche Zoologie,' Bd. ii., for the year 1862.

GENUS X. PLEUROCHILIDIUM, Stein.

Animalcules free-swimming, persistent in shape, not encuirassed, sub-
reniform and flattened, entirely ciliate ; oral fossa antero-ventral, ear-shaped,
having attached to its right margin a narrow undulating membrane ; tricho-
cysts often present.

This and the following genus, Ptychostomum, were instituted by Stein in the
' Bohmischen Sitzungsbericht,' Bd. ii., for the year 1860. Unfortunately, no figures
of either of the several specific forms referred to these genera have as yet been
published.

* 'Wieg. Archiv,' p. 219, Taf. vii. fig. 4, 1846.
t 'Bericht Akad. Berlin,' 1853.

GENUS PTYCHOSTOMUM. 541

Pleurochilidium strigilatum, Stein.

Body subreniform, depressed, the anterior extremity narrowest, obliquely
truncate, turned toward the right, the margin of this region crenulate ;
endoplast spherical, subcentral ; contractile vesicle situated posteriorly,
close to the right-hand border ; trichocysts large and scattered. Length
1-700". HAB. — Fresh water, among Lemna.

GENUS XI. PTYCHOSTOMUM, Stein.

Animalcules free-swimming, persistent in shape, not encuirassed,
asymmetrical, more or less ovate, depressed or plano-convex, the right-
hand margin convex, the left one concave, the posterior margin obliquely
truncate, oral aperture ventral, located towards the anterior extremity, anal
aperture situated on the left-hand side of the posterior extremity. Occur-
ring as endoparasites within the intestinal viscera of various Annulosa
and Mollusca.

Ptychostomum ssenuridis, Stein.

Body subovate, slightly depressed ; the right border convex, the left one
indented centrally; the ventral surface flat, the dorsal one convex, the
obliquely truncate posterior extremity curved towards the left in a spur-like
manner ; oral aperture subtriangular or acetabuliform, antero- ventral ; anal
aperture tubular, located near the left posterior border, enclosing a bristle or
lappet-like structure ; cuticular surface longitudinally striate, entirely ciliate,
cilia long and fine ; endoplast elongate-ovate, transversely placed ; contrac-
tile vesicle situated close to the right posterior margin, rosette-shaped at
systole. Length 1-288". HAB. — Alimentary tract of Scsmiris variegata.

The bristle or lappet-like organ described by Stein as situated within the anal
tube, is so anomalous that it appears an open question whether the so-called acetabu-
liform mouth is not an independent sucker or acetabulum, as in Haptophrya,
permitting the animalcule to fix itself to any desired point of the intestinal wall of
its host, and the so-called anal tube, with its bristle or undulating membrane,
an oral system corresponding closely with that of Panophrys, Microthorax, or
Trochilia.

Ptychostomum paludinarum, Stein.

Similar in shape to P. sanuridis, but the posterior extremity on the
right side obliquely truncate, bounded by a narrow undulating border,
which is at its left angle reflected inwards and projects to a short extent
upon the ventral surface ; oral aperture anteriorly located, cleft-like, occupy-
ing a transverse semicircular furrow that is parallel with the anterior margin
of the body ; endoplast elongate-oval, subcentral ; contractile vesicle single,
spherical, located immediately behind the endoplast. Length 1-168".

HAB. — Intestinal tract of Paludina impara and P. similis.

Diesing, ' Prothelminthen,' 1866, has proposed to distinguish this species
generically from the preceding animalcule under the title of Hysterocineta, but until

542 ORDER HOLOTRICHA.

figures and further details of the form and structure of the two specific types are sup-
plied such a separation is premature. Stein suggests that the posterior membranous
border in this species is possibly the analogue of the membranous sucking-disc of
the Trichodinopsis paradoxa of Claparede and Lachmann, which occurs under similar
conditions within the intestinal tract of Cydostoma elegans. On the other hand, it
would appear to exhibit an affinity with the genus Conchophthirus. The position
and structure of the so-called anal aperture, which exhibits so remarkable a modi-
fication in the preceding species, has not been determined in the present form.

Fam. X. PLEURONEMID-ffi, S. K.

Animalcules free-swimming, more or less ovate, ciliate throughout ; oral
cilia diverse in character to those of the cuticular surface; oral aperture
terminal or ventral, supplemented by an extensile and retractile hood-
shaped membrane or velum.

GENUS I. PLEURONEMA, Dujardin.

Animalcules ovate; oral aperture situated in a depressed area near
the centre of the ventral surface, supplemented by an extensile hood-
shaped transparent membrane or velum, which is let down or retracted at
the creature's will ; numerous longer vibratile cilia stationed at the entrance
of the oral cavity ; the general surface of the body clothed with long, stiff,
hair-like setae, occasionally accompanied by a few additional and longer
setae at the anterior extremity ; no abnormally developed posterior or caudal
seta ; the cortical layer usually containing trichocysts ; contractile vesicle
single, anteriorly situated.

By but few of the investigators of the Infusorial class of the Protozoa, up to the
present date, has the structural organization of the genus Pleuronema and its
allies been correctly estimated. The type of the genus, the Paramcerium chrysalis of
Ehrenberg, as first separated by Dujardin and subsequently studied by Perty and
Claparede and Lachmann and De Fromentel, has been altogether misinterpreted.
All these authorities agree in characterizing this form as being distinguishable from
Param&riunii merely in the development around the ventrally situated oral fossa of
numerous, abnormally long, recurved, retractile and vibratile cilia. That the outermost
of these so-called recurved vibratile cilia truly mark the peripheral contour of a
delicate hyaline membrane, has been conclusively ascertained by the present author,
and it is gratifying to find that Stein, in the very brief reference he makes to the
genus in the second volume of his ' Organismus,' expresses a corresponding view. This
interpretation of the characteristics of the genus was arrived at so long since as the year
1870, before having access to Stein's observations, and has been reconfirmed upon
innumerable occasions. An identical type of structure has likewise been found by
the author to obtain among the representatives of the genera Cyclidium and Uronema
of Dujardin, and exists also apparently in the genus Baonidium of Fresenius. This
transparent extensile membrane is by no means identical in form or function with
the tremulous flap or membrane possessed by the ciliate animalcules previously
described. Among these, this oral membrane has mostly an independent vibra-
tory action, and is immediately subservient to the purpose of bringing food-particles
to the mouth. In the case of Pleuronema, on the other hand, such membrane
is not vibratory, but fulfils the purpose of an exquisitely constructed bag-like trap,
raised or lowered at will, into which food-particles are swept by the action of the
special longer cilia stationed close to the mouth and enclosed within its borders. In

GENUS PLEURONEMA. 543

form, and in the manner of its extension and retraction, this membranous trap maybe
appropriately compared with the extensile hood of a carriage or an outside window-
shade, forming, when expanded, a capacious hood-shaped awning, and when not in
use being packed away in neat folds close around the animalcule's mouth. Some
distant homological relationship not improbably subsists between the hood-like
membrane of Pleuronema and its allies, and the delicate funnel-shaped membrane
characteristic of the recently discovered and extensive group of collared flagellate
Infusoria described in the preceding volume.

Pleuronema chrysalis, Ehr. sp. PL. XXVII. FIG. 55.

Body elongate-ovoid, compressed, from two to two and a half times as
long as broad, convex above, slightly concave beneath, subequally rounded
at the two extremities ; oral fossa situated near the centre of the ventral
surface, followed by a tubular pharyngeal passage ; the extensile membrane
or velum largely developed, its depth in full extension corresponding with
that of the body. Fine hair-like setae equal in length to one-half of the
diameter of the body, developed in even longitudinal rows over the whole
cuticular surface ; contractile vesicle anteriorly located ; endoplast sphe-
roidal, subcentral. Length 1-360" to 1-192". HAB. — Fresh water.

This species is identical with the Paranuzcium chrysalis of Ehrenberg, but is
referred to the present genus by Dujardin under the title of Pleuronema crassa.
Its habits are eminently social, closely resembling those of the more minute
Cyclidium glaucoma, but it is much less active. When first transferred to the stage
of the microscope for examination the animalcules rush to and fro across the field,
their setose cilia being the only appendages visible. In a little while, however,
they become quiescent, and letting down their delicate hyaline traps or vela, angle
for their accustomed food, often remaining anchored, as it were, in one spot for an
hour or more at a time. When disturbed, they spring briskly from one side to the
other with the aid of their fine body setae, after the manner of Cyclidium.

Pleuronema marina, Duj.

Body elongate-ovoid, slightly compressed, three times as long as broad,
obtusely pointed at each extremity ; the cuticular surface finely striate
longitudinally. Length 1-250". HAB. — Sea water.

Claparede and Lachmann have proposed to regard this form as identical with
P. chrysalis, but its average larger size and longer proportions, as given by Dujardin,
together with its marine habitat, seem sufficient to warrant its separate specific recogni-
tion. According to the figure given by its discoverer, the oral membrane is not
relatively so large as in P. chrysalis; the vibratile cilia of the oral system, on the
other hand, appear to be more extensively developed.

Pleuronema natans, C. & L.

Body subspherical, scarcely longer than broad, oral fossa very large and
deep ; extensile oral membrane or velum protrusible to a short distance
only ; fine short setae distributed throughout the cuticular surface. Length
of body 1-300". HAB. — Freshwater.

544 ORDER HOLOTR1CHA.

Pleuronema coronata, S. K. PL. XXVII. FIG. 56.

Body ovoid, compressed, twice as long as broad, extremities subequally
rounded, or slightly wider anteriorly ; oral fossa almost central ; cuticular
surface dotted with short, fine, rigid cilia or setae, whose length equal one-
sixth only of the diameter of the body ; a few supplementary, consider-
ably longer, fine, rigid setae projecting at various angles from the anterior
.extremity. Length of body 1-290". HAB. — Freshwater.

The author, not concurring with Claparede and Lachmann in referring the form
answering to the above diagnosis, and as figured by those authorities, to the Pleu-
ronema chrysalis of Ehrenberg, Dujardin, and Perty, a new specific title has been
created for its reception. The contour of its body is shorter and thicker than that of
P. chrysalis, from which it may also be readily distinguished by the short character
of the setae of the general cuticular surface and by the presence of supplementary
longer setae at the anterior extremity. The Pleuronema chrysalis, as figured by
Quennerstedt,* is apparently also identical with this type.

GENUS II. CYCLIDIUM, Ehrenberg.

Animalcules free-swimming, persistent in form, ovate, more or less com-
pressed ; oral aperture ventral, supplemented by a hood-shaped extensile
membrane ; body clothed with fine, rigid, hair-like setae, one or more abnor-
mally long caudal setae developed at the posterior extremity; contractile
vesicle single, posteriorly situated ; cortical layer not containing tricho-
cysts. Inhabiting salt and fresh water.

This genus, originally instituted by Ehrenberg, corresponds with the Atyscum
and Enchelys, in pars, of Dujardin, both of which are now accepted as comprising
forms fundamentally identical with Cyclidium glaucoma. Claparede and Lachmann,
as well as Stein, have further proposed to incorporate with this genus the Uronema of
Dujardin — a decision, however, from which the present author dissents, he having
frequently met with an animalcule which, while accurately corresponding with
Dujardin's Uronema marinum, differs essentially from Cyclidium as here defined, in
the character of the body cilia. The long caudal seta, and the situation of the
contractile vesicle, serve at the same time to distinguish the animalcules of this
genus from those of Pleuronema, which they otherwise closely resemble. The
several known species of Cyclidium are exceedingly minute, and require the employ-
ment of the higher magnifying powers of the compound microscope for the satis-
factory illustration of their characteristic membraneous trap. All the species are
very agile, springing about rapidly when disturbed by aid of the stiff setae with which
the general surface of their cuticle is beset, while at other times they progress
forwards leisurely by means of the vibratile cilia adjacent to the oral fossa.

Cyclidium glaucoma, Ehr. PL. XXVII. FIGS. 57 AND 58.

Body ovate, compressed, somewhat reniform, convex above, concave
beneath, little over twice as long as broad ; the oral aperture situated a
little in advance of the centre of the ventral surface ; setae of the general
surface very long and fine, their length equalling or exceeding that of the
breadth of the body, disposed in even longitudinal lines, the posterior or
caudal seta conspicuous, twice the length or more of those of the general

* ' Sveriges Infusoriefauna,' Lunds Universitets Ars-skrift, Tab. I. fig. 19, 1871.

GENUS CYCLIDIUM. 545

surface ; contractile vesicle postero-terminal ; endoplast spheroidal, sub-
central. Length of body 1-1250". HAB. — Pond water and infusions.

This species is one of the first Ciliate animalcules that makes its appearance in
hay or other vegetable infusions, in which it often swarms in countless numbers.
In addition to being essentially social in its habits, a certain community of action
appears to be maintained between the numerous individuals that are found together.
In this manner the springing to one side of a single zooid in the crowd is sure to
be responded to by another one in its vicinity, and the whole assemblage is pre-
sently set whirling and sporting together like a colony of house-flies in the genial
sunshine. As with flies, moreover, a strong light apparently offers a remarkable
attraction to these animalcules, it having been observed on many occasions that
they crowd to that portion of the microscopic field which is illuminated by the small
but brilliant pencil of light produced by the achromatic condenser when employing
a -jVmch object-glass, and follow it as different portions of the field are brought into
its focus by the stage movements. This tendency to assemble in the area of
strongest illumination was exhibited to an equal extent during the employment
of either lamp-light or ordinary daylight.

When actively darting about or swimming leisurely forwards, the characteristic
membraneous trap or velum of this species is, as in the case of Pleuronema, stowed
snugly away in transverse folds around the margin of the mouth, but is at once
lowered again to its full extent when, the moment's sport being over, the little
creatures come to anchor. The rapid multiplication of this form is chiefly
accomplished by the process of transverse fission, in connection with which it has
been observed that the characteristic membraneous velum takes its share. In young
individuals developed from germs, it was, however, ascertained by the author that
the extensile membrane, as in Uronema, does not make its appearance until the
animalcule has attained its adult dimensions, its aspect prior to this matured condi-
tion closely resembling that of Dujardirfs Enchclys triquetra, and which, in com-
pany with the Alyscttm saltans of that authority, and the Pletironema cyclidittm of
Claparede and Lachmann — wrongly represented as having the contractile vesicle
and characteristic seta at the anterior extremity — must undoubtedly be identified
with the immature state of the present species. Presuming the last-named form
to be distinct, Stein has proposed to confer on it the title of Cyclidium Clapartdi.

Cyclidium citrellus, Cohn sp. PL. XXVII. FIG. 59.

Body ovate or lemon-shaped, somewhat compressed, flattened ventrally
in the neighbourhood of the subcentral oral aperture, tapering abruptly at
the two extremities, about twice as long as broad ; surface of the integu-
ment faintly striate longitudinally, cuticular setae fine and evenly distributed,
not equalling the breadth of the body in length ; one long and two shorter
caudal setae developed at the posterior extremity ; contractile vesicle
postero-terminal. Length 1-600". HAB. — Salt water.

The presence of the two supplementary caudal setae, as well as the symmetrical
lemon-like contour of the body of this species, seem to distinguish it readily from the
preceding form ; by Cohn, who describes it under the title of Pleuronema citrellus^
the hood-shaped oral membrane is represented as a mere long, recurved seta.

Cyclidium arboreuxn, Ehr.

Body minute, suborbicular, ventral border slightly excavate, dorsal
surface rugose; cilia hair-like, scattered throughout. Length 1-1200".
HAB. — Among moss on trees.

546 ORDER HOLOTRICHA.

It is almost impossible to decide whether this species, briefly characterized as
above by Ehrenberg,* is rightly referable to the genus Cyclidium, or even in such a
case whether, though smaller, it is specifically distinct from C. glaucoma,

GENUS III. URONEMA, Dujardin.

Animalcules free-swimming, ovate or elongate, persistent in shape ; oral
aperture ventral, supplemented externally by an extensile trap-like mem-
brane or velum ; the general surface of the body covered with vibratile cilia ;
one or more long caudal setae developed at the posterior extremity.

This genus is readily distinguished from Pleuronema and Cyclidium by the
character of the appendages of the general cuticular surface, which, in this instance,
consist of flexible vibratile cilia in the place of stiff, hair-like setae.

Uronema marinum, Duj. PL. XXVII. FIGS. 60 AND 61.

Body elongate ovate, crenulate or rugose, from two and a half to three
times as long as broad, rather thicker posteriorly ; cilia of the general surface
of even length throughout, dispersed in parallel rows, about five of which
are exposed to view by the body as seen in profile ; caudal seta equalling
the body in length; contractile vesicle posteriorly located; endoplast
spherical, subcentral. Length 1-800".

HAB. — Vegetable infusions in salt and fresh water.

In its earlier condition this animalcule closely resembles the immature state of
Cyclidium glaucoma, it possessing no trap-like membrane, which is an after develop-
ment. In some of the youngest examples observed, only the longer oral cilia
were visible, the general surface of the body being apparently completely naked,
closely corresponding, in this condition, with the figure given by Dujardin of his
marine Acomia cydidium.\ Dujardin's Enchelys corrugatum,% again, an inhabitant
also of sea water, is likewise indistinguishable from the young of Uronema. The
extensile hood-shaped membrane in this species is smaller and far more difficult to
discern than in Cyclidium or Pleuronema, the animalcules but rarely presenting the
profile view requisite for its conspicuous exhibition. Although most abundantly
developed in salt water, a form, agreeing in all essential details with the present
species, has been recently obtained by the author from fresh water.

GENUS IV. B^EONIDIUM, Perty.

Animalcules free-swimming, persistent in form, elongate-ovate, or sub-
cylindrical ; the anterior border obliquely truncate, perforated by the oral
aperture, bearing circumferentially an extensile hood-like membrane or
velum.

Bseonidium remigens, Perty. PL. XXVII. FIG. 64.

Body elongate, subcylindrical, straight or more or less curved, from three
to four times as long as broad, the posterior extremity rounded, the anterior
one obliquely truncate, perforated by the oral fossa, and bearing an extensile
hood-like membrane or velum, whose width equals that of the breadth of

* 'Bericht Akad. Berlin,' 1853.

t Dujardin, ' Hist, des Zoophytes Infusoires,' pi. vii. fig. 5, 1841.

J Ibid., pi. vii. figs. lie and \\b.

GENUS LEMB US. 547

the body, numerous long vibratile cilia enclosed within the hood-like
membrane; cuticular cilia setose; endoplasm usually enclosing green
granules. Length 1-840" to 1-650". HAB. — Fresh water, among Chara.

The presence of an undulating membrane at the anterior extremity, correspond-
ing closely with that of Pleuronema, while suspected by Perty, is more conclusively
demonstrated by the figures and description of Fresenius,* from which the accom-
panying illustration is derived. According to the two authorities quoted, it swims
through the water, revolving on its long axis, creeps slowly, or springs from one
side to the other after the manner of Cyclidium, aided, apparently, under the last
conditions, by its setose cuticular cilia. Multiplication by transverse fission is
reported by its original discoverer.

Fam. XI. LEMBIDJE, S. K.

Animalcules free-swimming, elongate or vermicular, ciliate throughout,
oral and cuticular cilia diverse in character; oral aperture ventral, asso-
ciated with a prolonged crest-like membranous border.

The members of this very natural family group are characterized by the peculiar
crest- or sail-like contour of their supplementary adoral membranes. As yet but two
generic forms, Lembus and Proboscella, can be included in it. Both represent the
fruits of the most recent investigation.

GENUS I. LEMBUS, Cohn.

Animalcules free-swimming, elongate - clavate or vermicular, highly
elastic ; oral aperture ventral, subcentral, an extensile, subtriangular or
band-like, undulating membrane produced along a furrow on the ventral
surface, which extends from the anterior extremity backwards to the oral
aperture, cilia of larger size than those of the cuticular surface usually
developed along its inner border ; contractile vesicle conspicuous, posteriorly
located. Inhabiting salt water.

With reference to the peculiar modification of its characteristic undulating mem-
brane, the genus Lembus occupies among the Holotrichous Infusoria a position
corresponding to that held by Condylostoma and Blepharisma with relation to the
higher Heterotricha. Three species are now added to the type form introduced by
Cohn.

Lembus velifer, Cohn. PL. XXVII. FIGS. 62 AND 63.

Body elongate, lanceolate or clavate, from five to eight or ten times as
long as broad ; undulating membrane and adoral furrow commencing at a
short distance from the anterior extremity, extending backwards through
two-thirds of the length of the entire body, this portion of the body narrow
and linear, the posterior third cylindrical, more or less rounded posteriorly.
Adoral cilia long and fine, produced beyond the outer border of the undu- .
lating membrane; cilia of the cuticular surface rather longer towards the
anterior extremity ; surface of the posterior half of the body finely annulate
transversely; contractile vesicle posteriorly located. Length 1-480" to
1-240".

* ' Beitrage zur Kenntniss Mikroskopischer Organismen,' Frankfurt, 1858.

548 ORDER HOLOTRICHA.

HAB. — Salt water. Locomotion rapid, forwards or backwards in a
straight line, with the undulating membrane rapidly vibrating ; sometimes
stationary.

Cohn* compares the contour of the animalcules of this species, with their undu-
lating membranes expanded, to that of small boats with their sails spread ; multi-
plication by transverse and longitudinal fission, but chiefly the latter, was observed.
The attenuate anterior extremity of the body in advance of the oral region is de-
scribed as being very elastic, and capable of flexure in various directions, so much so,
indeed, that, divested of the characteristic undulating membrane, this type would
closely resemble a minute Loxophyllum or Amphileptus. Cohn suggests the probable
identity of this species with the Vibrio verminus of O. F. Muller, and also, perhaps,
with the Cyclidium elongatum of Claparede and Lachmann. While there can be little
doubt that this latter form should be rightly referred to the genus Lembus, the
description and figure supplied by its describers would appear to indicate its claim
to separate specific recognition. No indication is given of the transverse annulations
of the posterior body-half, nor of a difference in calibre between the cilia that clothe
the general cuticular- surface and those developed along the oral furrow which is so
distinctly observable in Cohn's species. Muller's type, on the other hand, may be
more readily identified with the form upon which the new genus Proboscella is here
established.

Lembus pusillus, Quennerstedtf

Body elongate, subcylindrical, about three times as long as broad,
rounded at each extremity, the anterior one slightly narrower ; undulating
membrane extending backwards to a distance of about one-half of that
of the entire body, not supplemented by a fringe of conspicuously larger
adoral cilia ; cuticular surface striate longitudinally, evenly and finely ciliate
throughout; contractile vesicle postero- terminal. Length 1-900" to 1-625".

HAB. — Salt water.

The longitudinal direction of the surface markings and smaller size of this species
serve to distinguish this type from that last described.

Lembus subulatus, S. K. PL. XXVII. FIGS. 66 AND 67.

Body elongate, subulate, four or five times as long as broad, rounded
and subcylindrical posteriorly, tapering gradually from the centre of the
body, and terminating anteriorly in a subulate, somewhat upturned point ;
oral aperture ventral, subcentral ; undulating membrane extending back-
wards from the anterior extremity to the oral aperture, continuous with a
conspicuous fringe of larger adoral cilia; cuticular surface exhibiting
neither longitudinal nor transverse striae ; endoplasm transparent, finely
granulate; contractile vesicle postero-terminal, endoplast spheroidal, situated
a little in advance of the median line. Length 1-750".

HAB. — Salt water, among decaying vegetable matter.

This species has been recently obtained by the author in considerable abundance
at St. Heliers, Jersey, associated with the Bacterial gloea-like film rising to the
surface of sea water containing seaweeds, Polyzoa, and other organisms in an

* "Neue Infusorien im Seeaquarium," 'Zeit. Wiss. Zool.,' Bd. xvi., 1866.
t ' Sveriges Infusoriefauna,' Lunds Universitets Ars-skrift, 1869.

GENUS PROBOSCELLA. 549

advanced state of decomposition. From L. pusillus, which it most closely resembles
in point of size, it may be distinguished by the relatively larger size of its adoral
cilia, by its more pointed anterior extremity, and by the absence of cuticular
striation. The extreme mobility or elasticity of this type would seem to surpass
that of any of the forms as yet referred to the genus. While occurring abundantly
in the open water, — where its comportment corresponds with that of the species
previously described, numbers were found imbedded in the substance of the glcea-
film itself, and through which they were busily occupied in slowly boring their way
in a worm-like manner, each body adapting itself readily to every vacuole within this
matrix, and assuming the most contorted and fantastic shapes. One of the more
ordinary sinuous contours exhibited under these last-named conditions is represented
at PL XXVII. Fig. 67. Natation is usually accomplished in an even straightforward
direction, or through rotation upon its long axis.

Lembus elongatus, C. & L. sp. PL. XXXII. FIG. 10.

Body very narrow, -elongate, somewhat bent, sub-even throughout, about
seven times as long as broad ; oral aperture in the centre of the ventral
surface, oral and cuticular cilia fine and short, even throughout, a long,
recurved, buccal seta (margin of the undulating membrane) extending
forwards from the oral aperture to the anterior extremity ; contractile vesicle
large, postero-terminal ; anal aperture in front of the contractile vesicle.
Length 1-300". HAB. — Salt water, Norwegian coast.

This animalcule, originally described by Claparede and Lachmann * under the
title of Cyclidium elongatum, cannot be referred with absolute certainty to the genus
Lembus, although the figure given of it, as here reproduced, would appear to favour
such location. Its habits, as recorded by these authorities, differ considerably
from those of either L. velifer or the succeeding species, it remaining for the most
part stationary among vegetable debris, and forming within the same an irregular
tube-like excavation, into which it rapidly retreats at will.

GENUS II. PROBOSCELLA, S. K.

Animalcules free-swimming, highly flexible, elongate-lanceolate, or ver-
micular ; oral aperture ventral ; an elongate, undulating membrane extending
backwards from the anterior extremity to the oral aperture, associated with
a fringe of longer adoral cilia ; a slender, extensile, digitiform or snout-like
appendage produced from the apical extremity ; the posterior extremity
bearing one or more caudal setae. Inhabiting salt water.

Proboscella vermina, Mull. sp. PL. XXVII. FIGS. 65 AND 650.

Body elongate-clavate, compressed, seven or eight times as long as
broad, the posterior half cylindrical or subfusiform, more or less rounded
posteriorly, the anterior portion linear, about one-half the diameter only of
the posterior part, terminating apically in a short, flexible, curved, retractile
and extensile fingerlike process ; oral aperture ventral, subcentral, situated
close to the junction of the more inflated posterior and narrower anterior
regions of the body ; undulating membrane irregularly triangular, extend-
ing from the oral aperture to within a short distance of the anterior

* ' Etudes sur les Infusoires,' 1 868.

550 ORDER HOLOTRICHA.

extremity ; cilia of the oral groove longer than those of the general surface,
but not projecting beyond the margin of the undulating membrane ; cuticular
surface delicately striate longitudinally, clothed with short, even cilia ; a
single, fine, straight, hair-like seta, about equal in length to the greatest
breadth of the body, produced from the centre of the posterior extremity ;
contractile vesicle conspicuous, postero-terminal ; endoplast double, con-
sisting of two equal-sized spheroidal moieties, situated one behind the
other a little in advance of the centre of the thicker posterior body-half.
Length 1-250". HAB. — Salt water.

It was at first proposed to include this species in the preceding genus Lembus,
but in the presence of the various forms now referable to that generic group,
none of which possess the anterior or posterior appendages that characterize the
present type, it has been deemed desirable to institute a new generic title for its
reception. The mobile and exceedingly flexible finger-like anterior process of
Proboscella presents, at first sight, some resemblance to the peculiarly modified apical
extremity of Trachelocerca or Lacrymaria, though it is not, as in those types,
perforated by the oral aperture. Its function appears to be entirely tentative, and
when not in use is, in common with the undulating membrane, packed away out
of sight. The habits of this species closely resemble those of Cyclidium glaucoma
and Uronema marina, it assembling in similar social companies, and for the most
part remaining stationary with its undulatory membrane extended and adoral cilia
rapidly vibrated. Under any disturbing influence it darts hither and thither with great
rapidity, exhibiting on such occasions, in common with Lembus velifer, the faculty of
swimming either forwards or backwards with equal facility. The examples- upon
which this new genus is here instituted were obtained in abundance from sea water
with decaying vegetation brought from Brighton in the month of May 1874.

It is only quite recently, February 1881, on referring to O. F. Miiller's original
figures and description of Vibrio verminus * to ascertain the extent of the resem-
blance subsisting between that form and Lembus velifer, suggested by Cohn, that
the author has been enabled to positively identify Miiller's organism with the type
now under consideration, such identification justifying the adoption of Miiller's
original specific title in the place of the new one of P. mucronatus that had been
previously decided on. Although in Miiller's illustrations of this species no trace
whatever is given of either the cilia, caudal seta, undulating membrane, or anterior
tactile appendage, the identity here maintained is substantially established with
reference not so much to their corresponding clavate outlines, which perfectly agree,
but to the fact that Miiller has clearly indicated in several of his figures the existence
of a subcentrally located vesicular structure, at once recognizable as representing the
peculiarly modified double nucleus or endoplast of the author's type, while a third
structure of apparently the same nature, as delineated by Miiller, corresponds in a
similar manner with the contractile vesicle. Any further doubts that might yet
remain are immediately disposed of by a reference to Miiller's original description,
which confirms the account of the structure and habits of this animalcule already
submitted, in so full and interesting a manner as to invite quotation in extenso.
This description runs as follows : —

" Vibrio linearis compressus, antice quam postice angustior.

" Animalculum hyalinum teres, motu vero lentiore crystallinum compressum, seu membrana
crystallina elongata, postica quam antica parte latior, apice subtruncata, basi obtusata. Interanea
nulla perceptibilia ; in medio tantum vesiculse duse sphaericse distantes, ac tertia intra marginem
posticam observabilis ; raro quasi linea longitudinalis prospicitur.

" Motus festinans antrorsum et retrorsum vacillatorius, antea parte aliquantum elevata."

Miiller further testifies to having on rare occasions observed animalcules either
in the act of conjugation or dividing by longitudinal fission. The examples he

* ' Animalcula Infusoria,' p. 57 and Tab. viii. figs. 1-6, 1786.

ORDER HOLOTRICHA, 551

figures as thus occupied are joined only by their central or oral regions, leaving the
two extremities free and often so far separated as to communicate to the conjoint
zooids a contour aptly compared by Miiller with that of a St. Andrew's Cross. It
is evident that the former of his two conjectures is the correct one ; the phenomena
presented being precisely parallel to those exhibited by two conjugating Paramaria,
while in no instance as yet known does the fissive process progress simultaneously
from the two opposite extremities leaving the central or oral region last connected.
No more fitting example than the present could perhaps be cited in illustration
of the advantages that may be derived from a consultation of the too often
neglected earlier authorities; the case in point, moreover, furnishes substantial
evidence of the comprehensive knowledge of the Infusoria that was capable of
attainment by skilled workers even with the indifferent instruments of the past
century. A reproduction of O. F. Miiller's most characteristic outline illustration of
his so-called Vibrio verminus is given at PI. XXVII. Fig. 65A.

Fam. XII. TRICHONYMPHID-aS, S. K.

Animalcules freely motile, but rarely swimming, their movements being
confined chiefly to twisting and writhing motions, more or less elongate or
vermicular ; cuticular surface entirely ciliate, accompanied apparently, in
some -instances, by an undulating membrane. Occurring as endoparasites
within the intestinal tracts of certain Neuropterous Insecta.

It seems desirable to comprise provisionally in one small family group the three
remarkable infusorial types, Trichonympha, Pyrsonympha, and Dinenympha, dis-
covered by Professor Leidy in the intestinal tract of the American white ant,
Termes flavipes. These, while first briefly described by him in the ' Proceedings
of the Academy of Natural Sciences of Philadelphia,' for the year 1877, form
the subject of a more extensive communication, with accompanying illustrations, to
the same journal, published in March 1881.* All three animalcules were found
by Professor Leidy associated together under the following circumstances. Seeking
for microscopic animals beneath stones and fragments of wood in the American forests,
his attention was attracted to the white ants in question, their intestines, as seen
through their translucent abdomens, being considerably distended with a brown sub-
stance. Feeling curious to ascertain the nature of this matter, it was examined
and found to consist largely of the three infusorial parasites here described, mingled
with minute particles of decayed wood, an abundance of Spirillum and the fila-
ments of an algal referable apparently to the genus Arthromitus, In many
instances, however, the Infusoria were present in such prodigious quantities as to
make up the greater portion of the bulk of the intestinal pulp.

The decision previously arrived at by the author to provisionally retain these three
genera in the single family group of the Trichonymphidae is in no way affected by
the more recent accounts and illustrations of the several species now to hand, and
is indeed fortified by the following extract from Professor Leidy's latest description :
" Of the parasites of our termite there appear to be three or four, or perhaps more,
distinct species of remarkable protozoans, but of this I am not positive, for I have
suspected that several, which I at first viewed as such, may be only different stages
of the same. On the other hand, certain forms which I have regarded as younger
stages of the species as I have distinguished them, may on future investigation prove
to be equally distinct." Or again, " In the following descriptions I have of course
attempted to represent them as they have appeared to me from time to time, but I

* Through the receipt of a separate copy of this communication, immediately on publication, the
author is especially indebted to Professor Leidy for the opportunity of reproducing in this treatise
his exquisite drawings and latest data elicited concerning the structure and habits of these remarkable
organisms.

552 ORDER HOLOTRICHA.

am not altogether satisfied with the results, and apprehend that in some cases I have
not interpreted the appearances correctly." It is in connection with this amount of
uncertainty that for the present pertains to these organisms that they are likewise
here provisionally correlated with the series of Holotrichous Ciliata distinguished by
the possession of supplementary membraniform expansions. In Pyrsonema, which
attains to the largest calibre, and may not improbably therefore be a more matured
condition of the companion forms, the lateral margin, see PL XXVIII. Fig. 18, is
often so modified as to closely resemble the simple membraniform type Trypanosoma
sanguineus delineated at PL I. Figs, i and 2 ; while in other instances, PL XXIII.
Figs. 1 6 and 17, an independently mobile cord-like structure, apparently indicating
an undulating membrane, is distinctly manifested.

M. C. Lespes, in a memoir on the " Organization of the European White Ant
Termes lucifugus" published in the ' Annales des Sciences Naturelles' for 1856, has
remarked that the contents of the intestines of that species consists also of a brown
pulp composed chiefly of a living agglomeration of Infusoria, an account of which
he proposed at some future time to give. This promise has not, however, so far been
redeemed, and it is greatly to be desired that some Continental histologist should take
the matter up, and ascertain whether these parasitic forms correspond with the Trans-
Atlantic types. A valuable suggestion respecting the examination of these and other
endoparasitic animalcules is contributed by Professor Leidy. Water proving too
thin a fluid for their preservation in a living state, a little white of egg was added,
and in this denser medium their normal form and characteristics were successfully
maintained for a considerable interval.

GENUS I. TRICHONYMPHA, Leidy.

Animalcules freely motile, exceedingly flexible and elastic, often con-
volute, mostly separable into two distinct regions consisting of a smaller
ovate head-like portion and a larger more or less inflated body ; cilia various
in length, apparently comprising three or four distinct series, one of these
exceedingly long and projecting considerably beyond the posterior ex-
tremity. Endoparasitic within the intestine of white ants.

Trichonympha agilis, Leidy. PL. XXVIII. FIGS. 1-15.

Body elongate-ovate or fusiform, from two to three or four times as
long as broad, the posterior extremity obtusely rounded or subacute,
according to the condition of contraction, the anterior extremity mammilli-
form and headlike ; cilia clothing the body forming apparently three or
four distinct series, the first and second shortest produced outwards and
downwardly from the anterior extremity ; the third longer, extending from
the anterior extremity through the whole length of the body, waving
downwards and outwards like the last ; the fourth set, longest of all,
extending from the apical end beneath the others in a longitudinal spiral
manner, beyond the posterior extremity of the body, and forming there
a loosely twisted fascicle with divergent ends ; oral aperture indistinct,
apparently taking the form of a rounded pore at the summit of the apical
extremity ; a narrow pharyngeal tube apparently extending thence back-
wards to a stomach-like dilatation which occupies the posterior two-thirds
of the body, and is usually filled with food-particles ; a granular nucleus-
like body located centrally close to the junction of the pharyngeal and food-
filled portion ; no contractile vesicle as yet detected. Length 1-300".

GENUS TRICHONYMPHA. 553

HAB. — Endoparasitic within the intestine of the American white ant,
Termes flavipes (Jos. Leidy).

The movements of this animalcule, as described by Professor Leidy, consist of
an incessant retraction or shortening and bending to and fro of the head-like
anterior region, accompanied by the rapid waving and swelling outwards of the long
ciliary hairs. Locomotion from one position to another is of rare occurrence, and
accomplished merely by a feeble jerking forwards for a short distance. The motions
of the longer cilia, forming the third series, are compared to the " flowing of a thin
sheet of water over the brim of a fountain vase or basin, swayed to one side or
to the other by a current of wind." The longest cilia, or fourth series, extending
beyond the posterior end of the body in a loosely twisted fascicle, are the least
active, but at times stretch outwardly and become more divergent at the ends, or
are applied more closely to the sides of the body. The most characteristic delinea-
tion of Trichonympha, illustrating the respective lengths and positions of attachment
of its four ciliary series as interpreted by its discoverer, is given at PI. XXVIII.
Fig. 2. In Fig. 3, while the two longer series are clearly separated, those belonging
to the first and second orders are indistinguishably blended. Pursuing another
simile, Professor Leidy remarks that the arrangement of the long cilia clothing the
body reminded him of the nymphs personified in a recent American spectacular
drama, the performers in which appeared having as their sole vesture and adorn-
ment long cords suspended fringewise from their shoulders, and which, as they
danced, were whirled around them in mazy undulations. This last-named likeness
quoted, originally suggested some affinity of the animalcules now under discussion
with the similarly endoparasitic Hexamitce described in the preceding volume.
These, when attached by their two posterior flagella, and spinning to and fro with
their four anterior appendages thrown into graceful convolutions around their bodies
in the manner recorded by the author (loc. tit., p. 320), might also with some appro-
priateness lay claim to the nymph-like simile suggested by Trichonympha; the dis-
tinctness of their respective types is, however, clearly demonstrated in connection
with the fuller data concerning Trichonympha now to hand.

As shown by Professor Leidy's recent drawings of this singular organism,
here reproduced, the variations of contour that a single zooid is able to assume in
accordance with the degree of extension, contraction, or contortion of the body
are almost infinite. Attention, in this connection, may be more especially directed
to those shorter and longer symmetrically helicoidal body-contours exhibited at
PI. XXVIII. Figs. 4 and 5. At Fig. 3, while the anterior portion alone is spirally
revolute, the several series of cilia are so disposed as to communicate to the
organism a tout ensemble suggestive of the expanded plumes of a bird-of-paradise
(Paradisea apodd). In his later description of Trichonympha, Professor Leidy
expresses himself in very doubtful terms concerning the existence of a definite oral
aperture ; so that the indication given of such a structure, together with that of a
pharyngeal passage, derived from his earlier account, must for the present be
accepted as provisional. That an oral aperture does exist is inferred from the almost
invariable presence internally of what appear to be fragments of woody tissue derived
from the food-materials of their hosts the termites. He at the same time remarks, " If
the irregular particles so commonly observed in the body-endosarc of Trichonympha
are really food-particles, I have been sorely puzzled and have failed to ascertain
how they obtained entrance into the body. I have watched myriads of individuals
hours together, without ever having seen one of them swallow or discharge a particle
of food. I have been unable to detect anything like a mouth. I could detect no
trace of a passage through the head-endosarc, nor ever saw a particle within it
which might be on its way to the body-endosarc."

Although the movements of Trichonympha agilis, when set free in an artificial
medium, are mostly limited to simple twistings, elongations, and contractions of
its body-mass, it would appear to possess the power of active locomotion within
the intestinal fluids of its host, wherein, as related by Dr. Leidy in his recent
paper, it may be detected amidst the dense concourse of its associates, gliding

VOL. II. G

554 ORDER HOLOTRICHA.

through and displacing them as it advances. The accredited immature phases of this
animalcule, as represented by Figs. 8 to 15 of the accompanying plate, are remark-
able both for their dissimilarity in general from one another and from the parent
form, circumstances which, as fully recognized by their discoverer, render their
identification with Trichonympha — pending the actual tracing of their development
into the adult type — purely tentative. In the imbricated modification delineated at
PL XXVIII. Figs. 9 and n more especially, it is worthy of note that a far closer
resemblance subsists between them and the phases of Pyrsonema vertens illustrated
by Figs. 19 and 20 of this plate, than between the same and the adult form of
Trichonympha. Respecting the zoological position and affinities of the type now
under discussion, Professor Leidy declares himself to be in some doubt whether to
regard it as a Ciliate Infusorian, a Gregarine, or a Rhabdocoelous Turbellarian, the
evidence, however, to his mind, favouring its relegation to a position with the first or
midway between the first and second groups. Affinities with the Gregarinida are,
in his opinion, indicated in connection with the separation of the adult body into
two distinct regions. A similar degree of differentiation is nevertheless manifested
in various ordinary Ciliate Infusoria. As illustrated by the generic types Lacrymaria,
Trachelocerca, Phialina, and Mesodinium, in all of which a separate head-like region
is distinctly recognizable. In all other respects Trichonympha conforms essentially
with the normal Holotrichous plan, the greater length and fineness of the ciliary
appendages being, seemingly, a more pronounced development of what commonly
obtains among the Opalinidse and other endoparasitic Infusoria, and in which a
matted or tufted character of the cilia is of frequent recurrence. It is at the same
time worthy of remark that the great length and apparently serial plan of disposi-
tion of the cilia in Trichonympha confer upon these organisms no inconsiderable
resemblance to the larvae of certain Chaetopodous Annelids, such as Nerine, in
which fascicles of long fine setae are in a somewhat similar manner produced,
chiefly from the anterior region of the body.

GENUS II. PYRSONEMA, Leidy.

Animalcules freely motile, more or less elongate, exceedingly flexible
and elastic, apparently finely ciliate throughout ; possessing in addition a
narrow, cord-like, undulating border which extends the whole length of the
body ; an oral aperture seemingly existing, but its position undetermined.
Endoparasitic within the intestine of white ants.

Pyrsonema vertens, Leidy. PL. XXVIII. FIGS. 16-20.

Body highly flexible and contractile, elongate-fusiform when extended,
clavate or pyriform in the contracted state ; while moving, exhibiting longi-
tudinally spiral and parallel lines, these at the extremities or at the angles of
flexure presenting the aspect of serrated projections, having a rapid waving
motion, resembling the movement of flames, and often communicating to
the body a screw-like aspect ; cilia when present short and of even length,
distributed throughout the entire surface of the body ; a narrow cord-like
prominence or membrane frequently extending the whole length of the
body, sometimes projecting at one extremity, moving in long, angular waves,
and flexing the body in accordance with its movements ; endoplasm finely
granular, enclosing a round or oval endoplast, which is located a little in
advance of the median line ; contractile vesicle not observed ; position of

GENUS DINEN YMPHA . 555

the oral aperture undetermined, but its existence made apparent by the
abundant presence of incepted food-particles. Length 1-200".

HAB. — Endoparasitic within the intestine of the American white ant,
Termes fiavipes (Jos. Leidy).

Like Trichonympha agilis, this animalcule is recorded by Professor Leidy as
usually retaining a stationary position j while stationary it at the same time frequently
exhibits an actively writhing or apparently twisting motion, or bends in a waving
manner from one extremity to the other. The consistence of the body-sarcode
appears to be of more delicate consistence than in the form last-described, the
animalcule undergoing rapid dissolution after removal from the intestine of its host,
and no clear distinction between the ectoplasmic and endoplasmic layers being
recognizable.

In the more recent account and figures of this species given by Professor Leidy,
its possession of cilia, previously supposed to exist but not actually determined, is in
certain cases fully verified. In a very considerable number of instances, however,
including both smaller and full-sized examples, the most rigid scrutiny failed to
detect the presence of any such appendages, this peculiarity being more particularly
distinctive of the larger, flattened, membraniform or srrew-like zooids illustrated
by PI. XXVIII. Figs. 18-20. While, excepting for the absence of cilia, these
screw-shaped animalcules considerably resemble the accredited immature phases of
Trichonympha depicted at Figs. 9 and 1 1 of the same plate, the membraniform
example with a serrated border, represented at Fig. 18, is far more appropriately
comparable with the simple membraniform organism referred to the genus Trypano-
soma, described at pp. 218 et seq. of the preceding volume and delineated at
Figs. 1-6 of PI. I. According to its discoverer, Pyrsonema vertens is a constant
companion of Tricfwnympha, frequently occurring in even greater abundance than
that type. As with the last-named form, the bodies of the present species are
usually more or less gorged with fragments, apparently of wood fibres and cellular
tissue, derived from the food of their host, though the channel by which it
obtained access to this position remains to be defined.

GENUS III. DINENYMPHA, Leidy.

Animalcules freely motile, more or less elongate ; exceedingly flexible
and elastic, finely and uniformly ciliate throughout ; oral aperture apparently
existing, but its position undetermined. Endoparasitic within the intestine
of white ants.

Dinenympha gracilis, Leidy. PL. XXVIII. FIGS. 21-24.

Body highly elastic, elongate-fusiform, flattened and band-like, fre-
quently twisted ; cuticular surface longitudinally striate, finely ciliate
throughout, a tuft or crest of apparently longer cilia frequently developed
at the anterior extremity ; the termination of the body, when contracted,
or the edges of the flexures when the body is bent, exhibiting a serrated
aspect; parenchyma translucent, enclosing numerous globular structures,
including apparently a subcentral endoplast and one or more vacuolar
excavations ; position of oral aperture not determined, but its existence
predicated through the abundant presence of enclosed particles of solid food.
Length 1-500" to 1-350".

G 2

556 ORDER HOLOTRICHA.

HAB. — Intestinal tract of American white ant, Termes flavipes (Jos.
Leidy).

This type is described by Professor Leidy as being the most minute and at the
same time the most abundant of the three forms with which Termes flavipes was
found endoparasitically infested. Its movements correspond almost precisely with
those of Trichonympha and Pyrsonympha, being limited mostly to active writhing
motions and to a lengthening and contraction of the body, accompanied by occasional
rotation on its long axis ; the animalcule otherwise maintains a nearly stationary
position. It has been recently suggested by its discoverer as by no means improbable
that Dinenympha may eventually prove to be a younger condition of Pyrsonympha.
If, however, his interpretation of the internal development of sporular elements, as
represented at PI. XXVIII. Fig. 21, is correct, its claim for independent recognition
would appear to be fully substantiated.

Appendix A. HOLOTRICHA-ASTOMATA.

Animalcules free-swimming, more or less completely and evenly ciliate
throughout ; possessing no oral aperture.

Fam. XIII. OPALINIDJE, Stein.

Animalcules free-swimming or temporarily adherent, mouthless, finely
and equally ciliate throughout, the cilia usually presenting a tufted or
matted aspect ; the anterior extremity sometimes armed with differentiated
organs of prehension, which may take the form of a suctorial disc, or
of one or more horny bands or uncini ; endoplast conspicuously developed,
sometimes multiple ; contractile vesicle present or absent. Occurring as
endoparasites within the recta and intestinal viscera of Amphibia and
Invertebrata.

The representatives of this family group were originally separated by Siebold
from the ranks of the ordinary Ciliate Infusoria and placed together with the
Peridiniidse, Euglenidae, and other Flagellate Protozoa — then supposed to be mouth-
less — in a separate section denominated by him the Astomata. All these flagellate
forms are now, however, with but few exceptions, known to possess either a distinct
oral aperture or the faculty of ingesting solid food-substances through a more or less
widely distributed area of their periphery ; while, in accordance with the views of
Stein and other recent authorities, the Opalinidas are to be regarded rather as an
aberrant and retrograde group of the ordinary Holotrichous series than as an entirely
distinct order of the Ciliata. Accepted upon such terms, the mouthless condition of
these aberrant Infusoria may be consistently interpreted as representing the outcome
of long subjection to that endoparasitic mode of existence which, among the normal
Rhizopoda, Annelida, and Crustacea, has apparently in an equivalent manner produced
the correspondingly mouthless groups of the Gregarinida, Cestoidea, and Rhizocephala.
The isomorphic, or more correctly the homoplastic, external resemblance that sub-
sists between many Opalinidae and certain Cestoid worms or Entozoa, is truly
remarkable, lending considerable weight to the opinion maintained by many earlier
writers that these animalcules are not independent beings, but embryonic or larval
conditions only of these higher Metazoa. The superficial resemblance cited is more
especially manifested in connection with the structural modifications exhibited by
the two genera Haptophrya and Hoplitophrya, in which, respectively, adhesive aceta-
bula or corneous booklets, similar to those of many higher Entozoa, are developed

FAMILY OPALINID&. 557

anteriorly and in a like manner enable their possessors to effect a tenacious hold
upon the intestinal walls of their selected hosts. A yet more remarkable peculiarity
suggestive of affinities in this same direction is, however, exhibited by certain species
of the genus Anoplophrya, in which, as exemplified most conspicuously in the type
presently described under the title of Anoplophrya prolifera, multiplication is effected
through the multiple segmentation of the posterior region of the body in a manner
closely resembling what obtains in the characteristic " proglottid " condition of the
tapeworms or Cestoid ea.

A very marked diversity of internal structure subsists between the several generic
forms of the present family group, all of which were formerly included in the
single genus Opalina. Thus, while in Opalina proper, as here defined, no trace has
yet been detected of the existence of a contractile vesicle, in the two generic forms
Anoplophrya and Hoplitophrya such an organ exists not only in a multiple form, but
more usually exhibits a regular serial plan of disposition, which may be regarded as
pretypifying the extended canal-like development of this element that obtains in the
allied genus Hoplitophrya and other higher Ciliata. The modifications observable in
the development of the endoplast or nucleus among the generic members of the
Opalinidae are also very extensive. With the majority of species this structure is found
to present a simple linear or band-like aspect, while in others it takes the form of one
or two simple ovate bodies. The most abnormal formula of endoplastic development
is, however, met with in the typical member of the genus Opalina, O. ranarum,
originally supposed to be entirely destitute of any such structure, but in which, through
the recent investigations more especially of Engelmann* and Ernst Zeller,f a perfect
multitude of minute spheroidal endoplasts or nuclei, each with a contained endo-
plastule or nucleolus, are shown to exist. Such multinucleate infusorial forms are
not inconsistently held by some authorities to possess a sound claim for acceptance
as multicellular organisms, and while not eligible for admission into the ranks of
the typical Metazoa, it would seem questionable whether they might not be appro-
priately relegated to such an intermediate zoologic series as the " Mesozoa,"
proposed by Ed. van Beneden for the reception of the singular endoparasitic genus
Dicyema of Kolliker, and which is actually treated by Claparede and Lachmann,
in their ' Etudes sur les Infusoires,' as a form most closely allied to the genus
Opalina. It has been more recently shown by Van Beneden, however, that Dicyema
is composed structurally of a central fusiform or subcylindrical axial cell around
which is superimposed a single layer of smaller, flattened, peripheral or cortical
cells, each possessing well-defined limits and a central nucleus, and having their
external surface covered with long, fine, vibratile cilia. As already suggested at
page 481 of the present volume, it would seem just possible that this long axial cell
in Dicyema is represented or pretypified among the Opalinidse by the abnormally
developed axial element or so-called nucleus that is met with in the genera
Anoplophrya and Hoplitophrya. The homoplastic resemblance subsisting between
the multinucleate Opalina. and the larval phases or " Planulae " of the Ccelenterate
sub-kingdom has been also referred to at page 480 of the present volume.

Taken in their entirety, the group of the Opalinidae can by no means be
regarded as representing the most lowly organized section of the Infusoria-Ciliata,
as has been maintained by Stein and some other authorities, for while the oral
aperture, by reason of the special surroundings, has either remained undeveloped
or become entirely obliterated, other structural features equal or excel in complexity
those encountered in any other infusorial types, and point indirectly, as just intimated,
to a relationship beyond the pale of the Protozoa.

Through the Dicyemida and Orthonectida, a direct relationship would appear to
be established between the Opalinidae and Scolecida, but it yet remains to be
determined by what ontogenetic process these several mouthless and essentially
endoparasitic organic groups have been primarily produced. With many, the inter-
pretation that they are retrograde offshoots only of the ordinary stomatode

* ' Morphologische Jahrbuch,' Bd. i. Heft, iv., 1876.

t 'Zeitschrift fiir Wissenschaftliche Zoologie,' I3d. xxix. Heft, iii., 1877.

558 ORDER HOLOTRICHA.

Annelidous and Infusorial classes is deemed sufficient. An altogether distinct
explanation, however, may be tentatively submitted for the consideration of those
who are disposed to concede to them an independent origin. In this connection
attention may be more especially directed to that correlation of an Opaline
animalcule with an undeveloped Metazoic ovum that has been instituted at page
480, previously quoted. As an afterthought to such correlation, the author has
been impressed with the idea that the Opalinidse may actually have originated from
the ova of the respective hosts which they are found inhabiting ; these ova, failing
the vital force requisite to carry them through the later segmentation phases
and thence to the parent form, having yet possessed a sufficient store of such
force to permit of their prolonged existence as independent beings able by the
simple process of fission to reproduce their kind. The very facts of these remark-
able organisms being without exception mouthless, and without exception endo-
parasitic, might be quoted as evidence in favour of this interpretation. The fact,
again, that side by side with the mouthless Opalince, as found in the common frog,
there subsists a ciliated Infusorium, Nyctotherus, possessing not only an oral but also
a highly differentiated anal aperture, militates against the consistent acceptance of
the former as degenerate scions of the ordinary Ciliate stock, and favours, on the
other hand, the alternative of their independent derivation.

The several genera into which this family group has been recently subdivided
by Professor Stein are readily distinguished by the characters afforded by the
presence or absence of contractile vesicles and by the nature of the supplementary
prehensile organs developed at the anterior extremity. The locomotive appendages,
or cilia, in the group of the Opalinidae, demand brief notice. Among the majority
of the forms included, they are distinguished from those of the more ordinary
Ciliata by their conspicuously matted or tufted aspect ; this peculiarity is, nevertheless,
shared by various other endoparasitic Infusoria, such as the genera Conchophthims,
Balantidium, and Nyctotherus, and doubtless fits them for locomotion in the denser
fluid medium which they inhabit.

GENUS I. OPALINA, Purkinge.

Animalcules mouthless, free-swimming, ovate or elongate; cuticular
surface delicately striate ; evenly ciliate throughout, furnished with no
supplementary organs of prehension ; endoplast spherical or ovate, single in
the youngest individuals, usually breaking up by repeated segmentation,
as growth proceeds, into innumerable minute, rounded, nucleolar bodies,
having a clear peripheral zone and a central nucleolus or endoplastule ;
no contractile vesicle. Entirely endoparasitic.

In accordance with the results of the latest investigation of the members of this
genus, as obtained by Ernst Zeller, the external surface of Opalina is not suffi-
ciently indurated to form a distinct and continuous cuticle, being composed of
numerous closely approximated, elastic, finely granular, muscular fibrillse, which
remain bound together during the life of the animalcule, but fall apart, as shown at
PI. XXVI. Fig. 20, on being treated with dilute acetic acid. It is the interstices or
lines of juncture between these fibrillae that impart to the Opalintz their character-
istic striated aspect. In the abnormal multiplication of the endoplast by duplication,
as manifested in the adult zooids, the representatives of this genus differ not only
from the remaining genera of the Opalinida, but from all ordinary Ciliata. The
method of separation of each endoplastular fragment, as reported by Zeller, exhibits
an additional peculiarity. The simply rounded form of the primitive single endo-
plast, under such conditions, is exchanged for a more or less elongate-ovate outline,
and is eventually separated into two equal halves through a central constriction ; the
original, minute, central, granular, endoplastule-like body or nucleolus does not, how-
ever, take part in this division, but remains intact in one half of the divided endo-

GENUS OPALINA. 559

plast, a new and independently developed endoplastule subsequently making its
appearance in the other moiety. The members of the genus Opalina proper, as at
present known, are parasites exclusively of the intestinal viscera of various tailed
or tailless Amphibia.

Opalina ranarum, Purk.
PL. XXVI. FIGS. 1-9, AND 20, AND PL. XXXI. FIG. 19.

Body broadly ovate or elliptical, flattened, scarcely twice as long as
broad, evenly rounded posteriorly, the anterior extremity bluntly pointed ;
the anterior half of the right-hand border projecting in a keel-like manner,
the opposite one evenly arcuate ; the cuticular surface finely striate through-
out, the striation on the dorsal surface taking a rectilinear-oblique course,
and on the ventral one an undulate or arcuate direction ; endoplast single
in the youngest animalcules, multiple in the adult zooids ; parenchyma
enclosing numerous minute, refringent, discoidal corpuscles ; increasing by
oblique or transverse fission. Length 1-45" to 1-30".

HAB. — Intestine and rectum of the common frog, Rana temporaria, and
toads, Bufo variabilis et cinereus.

This, the largest and most widely known representative of the genus Opalina, while
receiving its characteristic title from Purkinge and Valentin in the year 1835, was
figured and described by J. A. E. Goze under the name of the " Flimmerwalzen " or
" Flimmerquadrate " so long since as the year 1782. Through the recent investiga-
tions of Zeller we are now made familiar with the entire reproductive and develop-
mental cycle of this form, and with the various modifications undergone by it in its
onward growth from the embryo to the adult state. The minute cysts of this animal-
cule, PI. XXVI. Fig. 6, were abundantly met with by Zeller in the rectum and excreta
of Rana temporaria during the earlier months of the year, and on being placed
in vessels with the tadpoles or frog-larvae were abundantly devoured by the young
amphibia during the inception of their customary food. Within the intestinal tract of
their new host the wall of the cyst is ruptured, releasing the contained embryo. On
first making its exit from its transparent capsule, PI. XXVI. Fig. 7, the animalcule is
of an ovate shape, slightly flattened, with a rounded and widest anterior end and
pointed posterior extremity, the proportions being exactly the reverse of what is met
with in the parent form. Centrally, the parenchyma encloses a single conspicuous
spheroidal endoplast, and has, dispersed through its substance, an indefinite number of
the characteristic discoidal refringent corpuscles. Within a short interval, PI. XXVI.
Fig. 8, the body assumes a more elongate shape, is curved anteriorly slightly
towards the right, while the endoplast becomes divided into two or four equal sphe-
roidal portions. As growth proceeds a still more attenuate shape is arrived at, the
endoplast meanwhile multiplying within the parenchyma by progressive segmenta-
tions. In the most characteristic stage of its development the young Opalina
rananim presents an elongate-lanceolate contour, with a prominent keel-like anterior
border that agrees closely with the normal adult state of Opalina dimidiata and
Opalina similis, as delineated at Figs. 16 and ig of the same plate. The length of
the animalcule at this epoch of its existence is equal to four or five times that of its
greatest breadth, but it now begins to diminish these proportions and to increase in
i width. Widening out until the length scarcely exceeds twice its breadth, the
posterior extremity still retains its narrower and pointed outline, and the right
anterior angle its projecting keel. In this stage its contour corresponds remarkably
with that of the adult form of Opalina obtrigona, as illustrated by PI. XXVI. Fig. 10.
The posterior region of the body commences now to fill out, and becoming wider
and more rounded than the anterior or apical extremity, the normal shape and
size of the adult zooid, as represented by PI. XXVI. Fig. i, is ultimately attained.

560 ORDER HOLOTRICHA.

The reproductive phenomena, and origin of the primary encysted bodies, as
reported by Zeller, remain to be recorded. These, so far as it has been yet
ascertained, are brought about by a process of repeated binary fission of the
primary animalcule, agreeing in its earlier manifestations with that characteristic of
the majority of the members of the Infusorial sub-kingdom, but which in its later
phases follows a remarkably distinct plan. The subdivision of the adult zooids
of Opalina ranarum is accomplished in a twofold manner, partly by oblique
and partly by transverse fission. The first subdivision always takes an oblique
direction, PI. XXVI. Fig. 2, separating the animalcule into two halves, the fore-
most of which has a broader anterior and sharply-pointed posterior extremity,
communicating to it a close resemblance in contour to the ordinary zooids of Opalina
obtrigona, or to the half-grown examples of the present species, as already described.
The hinder half remains bluntly rounded posteriorly, and differs but slightly in
aspect from the adult form. The separated moieties continue multiplying by further
fission alternately in an oblique and transverse direction, until at length the divided
fragments do not exceed the i~7ooth to i-55oth part of an inch in length. These,
as delineated at PI. XXVI. Fig. 5, have an evenly ovate outline, their move-
ments gradually grow more languid, and in a little while they contract into a sub-
spherical form, and secreting around them a transparent indurated membrane,
become metamorphosed into cyst-like bodies, resembling those out of which the
adult zooids had been observed to develop. The average diameter of these cysts
varies from 1-1250" to i-iooo", though occasionally larger ones measuring 1-625"
were met with. The minutely divided Opalince were observed by Zeller at the
time of their encystment to enclose within their parenchyma a variable number of
the spheroidal endoplasts that characterize the parent zooid, though subsequent
to their encystment an important metamorphosis of these structural elements was
effected. So long as the spore-like cysts remained isolated in the outer water,
as voided with the excreta of the adult frogs, no modification in the character
or number of the contained endoplasts occurred, but on the cysts being devoured
by the young frog-larvae or tadpoles, these numerous endoplasts disappeared and
were replaced by a single larger spheroidal one. It was with such a single endo-
plast that the zooid usually broke its way from its cyst into the intestinal tract
of its new host, though occasionally the single endoplast did not take the place
of the more numerous minute ones until a little while after its exit from the
cyst. Whether the single larger endoplast is built up through the coalescence
of the several smaller elements, or whether these latter entirely disappear prior to
the appearance of the former, was not definitely ascertained, though the evidence
elicited most strongly supports the last alternative. The growth onward from the
minute newly released animalcule is but a recapitulation of the data already recorded.
In addition to the multiplication by fission productive of animalcules of gradually
diminished volume, and terminating in encystment, a simpler process of fission,
corresponding with that of the more ordinary Infusoria, and producing zooids which
grew again directly to the parent form, was found to take place later in the year,
including more especially the months of August and September. A more abnormal
elongate contour is not unfrequently presented by the animalcules of this species
when first emerging from the most minute cysts. Sometimes both these and the
smaller zooids resulting from the final phases of duplicative division, possess, as
shown at PL XXVI. Fig. 9, an altogether ragged outline, indicative of the soft and
glutinous consistence of the ectoplastic element.

In living examples of Opalina ranarum recently examined by the author when
dissecting frogs at the South Kensington Laboratory, it was observed that the
movements of the cilia during the progress of the animalcules over the smooth
surface of the glass object-carrier, exhibited a very singular aspect — vibrating rhyth-
mically in more or less even, parallel, wave-like series, and temporarily conveying
the appearance, as shown at PI. XXXII. Fig. 19, of their disposition in such order
upon the surface of the cuticle.

GENUS OPALINA. 561

Opalina dimidiata, Stein. PL. XXVI. FIGS. 16-18.

Body elongate, irregularly ovate, flattened, widest anteriorly, tapering
and more or less pointed posteriorly, three or four times as long as broad ;
the right border of the anterior extremity produced outwards in a keel-like
manner, the left border evenly arcuate throughout ; striations of the cuticular
surface straight and slightly oblique on the dorsal surface, arcuate on the
ventral one, entirely clothed with long, fine, matted cilia ; no contractile
vesicle ; endoplasts multiple, inconspicuous, first appearing in the young
zooids as a single central spherical body, afterwards breaking up by repeated
segmentation into innumerable smaller spherules, which become dispersed
through the substance of the parenchyma ; increasing by longitudinal and
transverse fission. Length of adults, 1-75" to 1-50".

HAB. — Intestine and rectum of the Edible Frog, Rana escutenfa, and Bufo
cinereus.

This species, as pointed out by Zeller, is identical with the form figured and
described by T. W. Engelmann* under the title of Opalina ranarum, but from which
it differs essentially both in the more attenuate contour of the adult zooids and in the
distinct hosts with which it is found associated. Overlooking this slight matter
of mistaken specific identity, the credit must be awarded to Engelmann of contri-
buting the earliest data of importance with reference to the structural and develop-
mental history of the Opalince. Previous to his researches connected with the
present species, the existence of an endoplast was entirely denied to the represen-
tatives of the genus ; the development of the animalcules from the minute encysted
bodies, as here described, was likewise unknown, while Zeller, taking as a basis and
following up with advantage the results of Engelmann's investigations, has left but
little to be added to our knowledge of their entire life-cycle. Engelmann's report of
the developmental phenomena of this Opalina dimidiata may be thus summarized :
On examining frogs in their larval or tadpole state, at a period when their bodies
measured a little more than a quarter of an inch in length, their intestinal tracts
were found to contain numerous spherical transparent cysts having a diameter of
about the i-2oooth part of an English inch. The riper of these contained a small,
elongate, ciliated body, curled upon itself and almost filling the cavity of the cyst.
Numerous elongate ciliate bodies, identical with those contained in the cysts, were
swimming freely in the surrounding fluid, presenting all the characteristics of typical
Opalince, but of smaller size and much more attenuate proportions even than the
adult examples. These free-swimming larval zooids, see PI. XXVI. Fig. 18,
are described as highly flexible, of elongate-lanceolate contour, with an attenuate
and tail-like posterior extremity; the cuticular surface is finely striate longitudi-
nally, and covered with a dense clothing of very fine cilia, which are often pro-
duced posteriorly as a brush-like tuft. In both the free-swimming and in the cyst-
enclosed animalcules a single, central, spherical endoplast of considerable relative
size was, while clearly visible under ordinary conditions, rendered still more conspi-
cuous by the addition of dilute acetic acid. Investigating more matured specimens
of the frogs' larvae, it was found that Opalince of gradually increasing size and stouter
proportions were contained within them, yielding at length examples in no ways
distinguishable in either shape or size from the ordinary adult zooids of Opalina
dimidiatum. Conjointly with this increase in the dimensions of the animalcules it
was further found that the endoplast or nucleus presented a progressively compound
character. Though single or simply spherical in the youngest individuals, it con-
sisted of two similar spheroidal bodies in rather older ones ; of four, eight, and
sixteen such bodies in still further developed zooids ; while in the full-grown and

* ' Morphologischc Jahrbuch,' Bd. I. Heft 4, 1876.

562 ORDER HOLOTRICHA.

perfectly matured representatives of the species, this primarily simple endoplast
had resolved itself into innumerable spheroidal fragments.

Although demonstrating the existence and extensive distribution of the endo-
plastic system in this species, and the development of the adult forms from the
minute encysted bodies, Engelmann has contributed nothing further towards its
reproductive history, though he was inclined to infer that the minute encystments
first observed were derived immediately from the ultimate spheroidal segmentations
of the endoplast of the fully matured zooids. This hiatus in the developmental
cycle of the type now under consideration has been successfully filled in by Zeller,
who has shown that the fully grown animalcules break up by continuous fission in
the manner already described of Opalina ranarum, the ultimate fragments forming
similar encystments. A slight variation in this process of fission is exhibited by
O. dimidiatum, the subdivision being accomplished alternately in a longitudinal and
transverse direction instead of in an oblique and transverse one, as occurs in the
preceding type. In the latter instance it frequently happens that the two separated
portions are of very unequal dimensions, the posterior moiety being considerably
the smaller. This unevenness of the calibre of the segmented moieties recurs, as
presently shown, in a yet more conspicuous form among certain representatives of
the allied genus Anoplophrya.

Opalina obtrigona, Stein. PL. XXVI. FIGS. 10 AND n.

Body flattened, subtriangular, about twice as long as broad ; the anterior
border considerably the widest, tapering thence gradually backwards to-
wards the attenuately pointed posterior, the right margin convex, the left
one concave; cuticular striations taking a rectilinear-oblique course on
the dorsal surface, and an arcuate direction on the ventral one ; endoplasts
numerous, spheroidal, dispersed throughout the substance of the paren-
chyma ; parenchyma enclosing also minute discoidal corpuscles ; segmen-
tation longitudinal and transverse. Length 1-50" to 1-40".

HAB. — Intestine of the Tree-Frog, Hyla Etiropaa.

The normal adult contour of this species closely resembles that of the half-
grown condition of Opalina ranarum, and also the anterior zooid produced by
the first act of fission of that type. The development of the ordinary zooids
from cyst-like bodies resulting from the minute subdivision of the adult animalcules,
as also the multiplication of the species by simple fission, has been observed by
Zeller: The formation of cysts takes place in the spring months, April and May,
when the frogs are spawning and lead a temporary aquatic life. Being then cast
out with the ordinary excreta into the surrounding water they are there devoured by
the young tadpoles, and begin anew their cycle of development.

Opalina intestinalis, Ehr. sp. PL. XXVI. FIG. 19.

Body identical in form with Opalina dimidiata, but smaller in size, en-
closing a single ovate endoplast only, or two such endoplasts situated
toward the anterior extremity of the body, and united to one another by a
thread-like commissure or funiculus ; dividing by longitudinal and transverse
fission. Length i-ioo" to 1-75".

HAB. — Intestine of Pelobates fuscus and Rana esculenta.

This species, upon which Ehrenberg conferred the name of Bursaria intestinalis,
represents one of the oldest known infusorial forms, it finding a place among the
text and figures of Leeuwenhoek's ' Opera Omnia,' p. 49, fig. A, 1683, under the

GENUS ANOPLOPHRYA. 563

title of 'Animalcula in stercore Ranarum.' By Stein it has been more recently
referred to the next genus, Anoplophrya, but in the absence of all trace of
the contractile vesicle, which forms so distinctive a feature of the members of that
generic group, it appears desirable to retain it among the ordinary Opalina. Sub-
division by longitudinal and transverse fission, and the production through this
process of reproductive cysts, as in the previously described species, has been
observed by Zeller, who has, however, without sufficient apparent cause, proposed
to substitute for this form the title of Opalina similis.

Opalina caudata, Zeller. PL. XXVI. FIGS. 23 AND 24.

Body irregularly ovate, about twice as long as broad ; the dorsal surface
convex and inflated, the ventral one flattened ; the posterior extremity
produced as a short, conical, tail-like appendage ; cuticular striae obliquely
directed, widely separated in comparison with those of the preceding
species ; endoplasts two in number, subcentral, united to each other by a
sinuous thread-like commissure ; dividing by longitudinal and transverse
fission. Length 1-120". HAB. — Intestine of Bombinator igneus.

The multiplication of this species through the minute subdivision and cyst-
formation of the primary zooids, as in the four preceding types, was observed by
Zeller to take place during the months of April, May, and June. A distinctive
feature of this species, in addition to its characteristic contour, is afforded by the
wide separation of the cuticular striations, and by the apparent density of the clear
cuticular layer. In the possession of two connected endoplastic bodies this type
agrees with the form last described. At the time of segmentation these two
structures become isolated within the anteriorly and posteriorly separated moieties,
but quickly double themselves again by redivision. Not unfrequently, the sub-
division of the endoplasts precedes the segmentation of the animalcule's body,
which is therefore for a while provided with four endoplastic structures.

GENUS II. ANOPLOPHRYA, Stein.

Animalcules mouthless, free-swimming, ovate or elongate, entirely
ciliate ; endoplast conspicuous, mostly band-like, and axial ; contractile
vesicle or vesicles well developed ; possessing no supplementary organs
of prehension. Occurring as parasites within the intestinal viscera of
various Invertebrata.

Anoplophrya naidos, Duj. sp. PL. XXVI. FIG. 12.

Body variable in form, elongate-ovate or elliptical, considerably flat-
tened, bluntly rounded at each extremity, the anterior one sometimes
obliquely truncate, averaging from three, to four or five times as long as
broad ; cuticular surface longitudinally furrowed or striate, entirely ciliate ;
contractile vesicles numerous, usually disposed in a single line down one lateral
border, occasionally forming a second line on the opposite side ; endoplast
axial, thick and band-like, coarsely granular, extending nearly the whole
length of the body. Length 1-200".

HAB. — Intestine of Nats serpentina.

The highly developed contractile vesicles of this species were not recognized by
Dujardin when he first described it under the name of Opalina naidos, but have

564 ORDER HOLOTRICHA.

been since successfully demonstrated by Professor E. Ray Lankester.* As inti-
mated by this last-named authority, a satisfactory exhibition of these structures in
their natural condition is best attained by examining the creatures immersed within
the intestinal fluids of the host they infest Placed in pure water the pulsating
action is at once suspended, while by the process of endosmosis their form and
character becomes entirely metamorphosed. A species apparently identical with
the present one, but of much larger size, 1-50", was obtained by Professor Lan-
kester from a species of Lumbriculus; no less than thirty contractile vesicles were
observed in some of the larger examples of this variety.

Anoplophrya nodulata, Miiller sp.

Body elongate-ovate or elliptical, usually somewhat widest anteriorly ;
cuticular surface longitudinally striate ; entirely and finely ciliate ; endoplast
axial, band-like ; contractile vesicles numerous, forming a linear series on
each side of the band-like endoplast. Length 1-200".

HAB. — Marine, within the intestine of Nais littoralis.

This species, more generally known by the name of Opalina lineata, conferred
upon it by Max Schultze,f is undoubtedly identical with the type inhabiting the
same host figured and described by O. F. Miiller, ' Zoologia Danica,' 1788, under
the title of Leucophrya nodulata. This earlier investigator has not only clearly
indicated in his drawings, loc. at. Taf. Ixxx.figs. a-i, the respective contours and plan
of disposition of the central endoplast and double line of contractile vesicles, but
also attests to the manner of multiplication through the separating-ofT of a small
nodular segment only of the posterior region of the body. Sometimes two imper-
fectly separated segments are recorded as remaining consentaneously attached to
the primary zooid, such reproductive phenomenon preparing the way for the very
remarkable modification of the process that obtains in the species next described.

Anoplophrya prolifera, C. & L. sp. PL. XXVI. FIG. 14.

Body elongate-linear, widest anteriorly ; cilia of cuticular surface dis-
posed in longitudinal lines in correspondence with the superficial longi-
tudinal striations ; endoplast axial, elongate, subcylindrical ; contractile
vesicles numerous, disposed in two longitudinal rows, one on each side
of the central endoplast ; increasing by multiple transverse segmentation
of the posterior body-half. Length 1-70".

HAB. — Within the intestinal cavity of various marine Annelids, Norwe-
gian coast.

This species, described by Claparede and Lachmann under the title of Opalina
prolifera, is acknowledged by them to so closely resemble the O. lineata of Schulze
(Miiller's Leucophrya nodulata) as to be possibly identical with that type. A most
remarkable feature of this form, however, and one which seemed to justify its
description by Claparede and Lachmann as a distinct form, is connected with
its mode of increase. This is effected by multiple instead of by simple transverse
fission, the posterior portion being often, as shown in the accompanying figure,
divided into as many as five nodular segments, each of which becomes consecutively
separated off to form an independent zooid. This singular mode of multiplication,
while occurring in no other known member of the Infusorial class, is highly charac-
teristic of what obtains among certain lower Annelida, such as Syllis or Nais,

* ' Quarterly Journal of Microscopical Science,' p. 143, 1870.

t ' Beitrage zur Naturgeschichte der Turbellarien, ' Greifswalde, 1851.

GENUS ANOPLOPHRYA. 565

and is still more suggestive of the strobiloid mode of reproduction presented by
Tcenia and other Cestoidea. The Rhabdocoelous Turbellarian genus Catenula,
again, so called from the chain-like aggregate of imperfectly separated zooids
distinctive of its normal growth-form, may be cited as yielding yet another
appropriate simile. To the advocates of the lower Annelidan affinities of the
O^alince, this interesting species would seem to offer special inducements for further
investigation.

Anoplophrya mytili, Quenn. sp. PL. XXVI. FIGS. 26 AND 27.

Body ovate, rounded at both extremities, slightly narrower posteriorly ;
about one and a half times as long as broad ; flattened and meniscoidal in
lateral view ; contractile vesicle single, posteriorly located ; endoplast
elongate-ovate, subcentral ; entire cuticular surface covered with long, fine,
tufted cilia. Length 1-400".

HAB. — Marine, occurring as a parasite of the common mussel.

Figured and described by A. Quennerstedt * under the title of Opalina mytili.

Anoplophrya inermis, Stein.

Size and contour agreeing with that of Hoplitophrya secans, but without
the ventral horny band. HAB. — Intestine of Clepsine binoculata.

Anoplophrya striata, Duj. sp.

Body elongate-ovate or elliptical, rounded at each extremity, about twice
as long as broad ; endoplast band-like, extending axially through nearly
the whole length of the body ; contractile vesicles numerous, disposed in
somewhat uneven lines on each side of the axial endoplast. Length 1-170".

HAB. — Intestinal cavity of the common earth-worm.

This species, while figured and described by Stein under the title of Opalina
lumbrici,\§ identified by him with the form that previously received from Dujardin
the name of Leucophrys striata, and should undoubtedly retain the prior specific desig-
nation. The Leucophrys nodulata of Dujardin does not agree with M tiller's type
bearing that name, but represents an altered condition only of the species now
under notice. Excepting for the absence of the horny armature this animalcule
corresponds in size and aspect with Hoplitophrya armata ; the habitat being likewise
identical, it is not improbable, as suggested by Stein, that it is an imperfectly
developed phase of that form.

Anoplophrya branchiarum, Stein.

Body shortly cylindrical, equally rounded at the two extremities, about
one and a half times as long as broad ; endoplast band-like, axial, extending
throughout the body ; contractile vesicles numerous, minute ; increasing by
transverse fission. Length 1-216."

HAB. — Occurring as an endoparasite of the fresh-water shrimp, Gam-
marus pulex.

This species, first described by Stein in the year 1852^ occurs in swarms within
the branchial appendages of the Amphipodous Crustacean above named, its frequent

* ' Sveriges Infusoriefauna,' ,1867.

t 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. iii.

566 ORDER HOLOTRICHA.

companions as ectoparasites of the same host being Spirochona gemmipara, Lageno-
phrys amptilla, and L. nassa, and the remarkable Acinete type Dendrocometes
paradoxus.

Anoplophrya clavata, Leidy sp. PL. XXVI. FIG. 21.

Body clavate, about five times as long as broad, obliquely and concavely
truncate anteriorly, the front margin often expanded and hatchet-shaped,
the posterior region attenuate, rounded, or acuminate ; cuticular surface
longitudinally striate ; parenchyma granulate, colourless ; endoplast not
observed ; an even row of six or eight spherical contractile vesicles disposed
along the longer or dorsal border. Length 1-200" to i-ioo".

HAB. — The visceral cavity of Limibriculus limosns.

This species, originally described by Professor Leidy as Leucophrys clavata, is
apparently referable to the present genus. Multiplication by even transverse fission
was frequently observed. The characteristic anterior truncation is not conspicuous
in the posteriorly produced zooid until some time subsequent to its separation from
the anterior moiety.

Anoplophrya cochleariformis, Leidy sp. PL. XXVI. FIG. 25.

Body elongate, curved, somewhat variable in form ; the anterior half or
third ovate and inflated, the posterior portion narrow and subcylindrical,
gradually tapering to its extremity, but sometimes exhibiting a secondary
smaller terminal inflation ; contractile vesicles six or seven in number,
forming a row along the margin of the narrower posterior region ; endoplast
broadly ovate, filling the larger portion of the inflated anterior segment.
Length 1-175" to 1-130".

HAB. — Intestinal cavity of Lumbriculus tennis.

This species was originally described by Professor Leidy * under the name of
Lwicophrys cochleariformis. The contractile vesicles and endoplast, although not
mentioned in his brief description, are clearly indicated in his accompanying
drawings.

Anoplophrya (P) socialis, Leidy sp.

Body highly contractile and variable in form, ovate, cordate, fusiform, or
globular ; cuticular surface longitudinally striate, entirely ciliate ; enclosing
numerous internal vacuoles. Length 1-75" to i-ioo".

HAB. — Intestinal tract of the American fresh-water Polyzoon, Urnatella
gracilis, Leidy.

This animalcule, likewise briefly described by Professor Leidy as a species of
Leucophrys, apparently belongs to the present generic group.

Anoplophrya vermicularis, Leidy sp.

Body subcylindrical, eight or ten times as long as broad, slightly taper-
ing or subacute posteriorly ; the anterior end rounded and flattened ; cuti-
cular surface striate longitudinally, shortly and finely ciliate ; parenchyma
white, finely granular; contractile vesicles numerous, twenty to thirty in

* ' Journal Academy Natural Science Philadelphia,' ser. ii. vol. iii., 1855.

GENUS A NO PL OPHR YA. 567

number, forming usually a single but sometimes a double longitudinal
series ; endoplast band-like, axial ; nearly as long as the body. Length
i -60".

HAB. — Rectum and intestine of the fresh-water snail, Paludina decisa.

Professor Leidy, in describing this species * also as a species of Leucophrys,
remarks that it is often so abundantly developed in its selected host as to completely
distend that portion of the intestine occupied, resembling in their crowded condition
a mass of writhing worms. Besides swimming with the aid of its cilia the species is
capable of effecting progress after the manner of a worm by the contortions of its
body, which may be flexed into a sigmoid contour or be even doubled upon itself.
The endoplast, while scarcely perceptible in the fresh condition, becomes clearly
delineated as the animalcules approach dissolution.

Anoplophrya convexa, Clap. sp.

Body oval, meniscoidal, obtusely rounded at each extremity, about one
and a half times as long as broad ; cuticular surface finely striate longitudi-
nally ; contractile vesicles very large, varying in number from four to six,
forming a unilateral row ; endoplast axial, about half the length of the body.
Length 1-178".

HAB. — Marine, within a species of Phyllodoce, separate from that infested
by Anoplophrya ovata. Multiplication by fission or segmentation not
observed.

This and the three succeeding species are not included by Claparede and Lach-
man in their larger work ' Etudes sur les Infusoires,' but are described by Claparede
only, in his ' Recherches sur les Annelides Turbellarie's observes dans les Hebrides,'
published at Geneva in the year 1860. All four are there referred to the typical
genus Opalina.

Anoplophrya ovata, Clap. sp.

Body ovate, equally rounded at each extremity, not quite twice as long
as broad ; cuticular surface longitudinally striate ; contractile vesicles
spherical, five or six in number, forming a single lateral row ; endoplast
axial, elongate, about one-half the length of the body. Length 1-200".

HAB. — Marine, within a species of Phyllodoce. Multiplying abundantly
by segmentation of the posterior region, the endoplast taking its share in
the division.

Anoplophrya filum, Clap. sp. PL. XXVI. FIG. 13.

Body ribbon-like, flattened, long and slender, about twelve times as long
as broad ; cuticular surface finely ciliate throughout, the cilia at the posterior
extremity slightly longer, forming a somewhat brush-like tuft ; cuticu-
lar surface granular, not conspicuously striate ; contractile vesicles minute,
numerous, about twenty in number, forming a single subcentral row ; endo-
plast not observed ; increasing, as in Anoplophrya lineata and A . prolifera,
by posterior segmentation. Length 1-65".

HAB. — Marine, within the alimentary canal of Clitellio arenarius.

* ' Proc. Acad. Nat. Sci. Philadelphia,' 1877, p. 259.

568 ORDER HOLOTRICHA.

Anoplophrya pachydrili, Clap. sp.

Body irregularly ovate or subpyriform ; widest and truncate posteriorly,
pointed and narrowest anteriorly ; two or three contractile vesicles forming
a row on each lateral border ; endoplast not observed. Length 1-350".

HAB. — Marine, within the intestine of Pachydrilns verrucosits.

GENUS III. HAPTOPHRYA, Stein.

Animalcule mouthless, ovate or elongate, the anterior extremity modified
so as to form an adhesive sucking-disc ; the remaining cuticular surface
ciliate ; contractile vesicle and endoplast conspicuous, the former mostly
canalicular. Entirely endoparasitic.

Stein, in his original subdivision of the somewhat heterogeneous assemblage of
animalcules previously referred to the single genus Opalina, into four groups of
corresponding taxonomic value, proposed to distinguish those characterized by the
possession of an adhesive acetabulum by the title of Discophrya. This generic
name he introduces in his essay relating to the subdivision of the Holotrichous
Infusoria contributed to the ' Sitzungsberichte der konigl. bohmischen Gesellschaft
der Wissenschaften' for the year 1860, and uses also in his sketch of the Holotri-
chous order contained in vol. ii. of his ' Organismus der Infusionsthiere,' published
in the year 1867. In his final classification table of the Ciliata, reproduced at p. 2 10*
of vol. i., he, however, without any explanation, substitutes in its place tha£ of
Haptophrya. This name, having been since adopted by other Continental
authorities, is accordingly preferentially adhered to in the present treatise. A
distinctive feature of the genus, shared also by some few members of the armed
Hoplitophryce., is connected with the contractile vesicular system. In the previous
genus Anoplophrya, this is generally found to take the form of one or two linear
series of independently pulsating spheroidal vacuoles, while in the present one,
Haptophrya, it — in all species so far known — consists of a single canal-like reservoir
that is produced throughout the greater extent of the creature's body. Under
abnormal conditions, such as the transfer of the animalcules to pure water, it has
been shown by Ray Lankester, in the case of Anoplophrya naidos, that two or more
of the normal spheroidal vesicles may run together, producing a more or less
extensive canal-like lacuna. There can, therefore, be but little doubt that the
characteristic canal-like contractile vesicle of Haptophrya represents a more highly
differentiated modification of the linear series met with in the preceding genus.

Haptophrya planariarum, Siebold sp. Woodcut, p. 569.

Body wedge-shaped or subcylindrical, about six or seven times as long
as broad ; rounded and widest anteriorly ; the posterior extremity pointed ;
the anterior region bearing a semicircular adhesive disc, the central portion
of which is apparently naked, while its outer margin is provided with a
fringe of cilia of larger size than those which clothe the remaining cuticular
surface ; contractile vesicle canal-like, extending nearly the whole length
of the body ; endoplast elongate-ovate, granular. Length of body 1-36".

HAB. — Intestinal cavity of various Planarians, including more especially
Planaria torva.

* By accident, the two generic names Hoplitophrya and Haptophrya have in this table been
missp«lt Hoplophrya and Haplophrya, — ED.

GENUS HAPTOPHRYA.

569

This form, selected by Stein as the type of his new genus Haptophrya (Disco-
phryci), is identical with the Opalina planariarum of Siebold and the Opalina poly-
morpha of Max Schultze. In the original illustrations of this species given by
the last-named authority,* and reproduced in the accompanying woodcut, the aceta-
buliform organ, as delineated most distinctly at Fig. 2, forms a complete circle and
is not bordered with cilia of conspicuously larger size than those which clothe the
general cuticular surface. The body is also seen, from Figs, i and 2, to exhibit in
its fully developed state a remarkable disparity of size in different regions, the
part succeeding the anterior disc-like organ being much strangulated and neck-like.
The endoplast is represented as a small, granular, ovate body, located close to the
posterior extremity.

Haptophrya. plattaruirum, Siebold sp. — i and 2. Adult, fully extended animalcules in dorsal and lateral aspect.
3. Undeveloped zooid ; n, endoplast or nucleus ; c, canal-like contractile vesicle ; ac, acetabulum. X 250. (After
Max Schultze.)

Haptophrya gigantea, Maupas. PL. XXXII. FIGS. 14 AND 15.

Body elongate, cylindro-conical or wedge-shaped, tapering from the
front backwards, a little over twice as long as broad ; the anterior extremity
depressed, about twice the breadth of the posterior region, provided with a
circular adhesive disc; the ectoplasmic layer or cuticle longitudinally
striate, but non-contractile, thickly clothed with fine, short, vibratile cilia,
which are disposed in close-set longitudinal rows ; cilia of somewhat larger
size bordering the inner margin of the adhesive disc ; contractile vesicle
canal-like, irregularly sinuous, extending from the adhesive disc to the
posterior extremity of the body ; endoplast elongate ovate or ellipsoidal,
freely movable within the internal parenchyma or endoplasm. Length
1-25". Increasing by multiple transverse segmentation.

HAB. — Intestine of Bufo panthcrinus and Discoglossus pictus, Algiers.

This fine Opalinid, first discovered and described by M. E. Maupas t in connec-
tion with the two above-named Batrachians obtained from Algiers, has been found
more recently by M. A. Certes j inhabiting examples of Bufo pantherinus, derived from
the neighbourhood of Constantine. Through the independent investigations of these

* ' Ein Beitrag zur Naturgeschichte der Turbellarien,' Greifswalde, 1851.

f ' Comptes Rendus,' Ixxxviii. p. 921, 1879.

+ ' Bulletin de la Societe Zoologique de France,' torn, iv., 1880.

VOL. II.

il

570 ORDER HOLOTRICHA.

two authorities, a tolerably exhaustive knowledge of its structure and developmental
history has been arrived at. Some of the more important data thus placed on record
are herewith epitomized. Maupas, in his account of the circular sucker occupying
the depressed portion of the anterior extremity, and other details, states that the first-
named structure is formed by the retreat inwards of the wall of that broader surface,
which may be denominated the ventral one. The action of the sucker is compassed
by cords of sarcode which, starting from its inner wall, are attached to the opposite
or dorsal body-wall. The surface of the body is clothed with very close rows of
cilia. Four or five rows may be counted within the space of • 01 mm. (1-2500" Eng.),
and in the concavity of the sucker they are half as numerous again. The cilia are
set very closely together — about thirteen or fourteen in • o i mm. They form the
only organs of locomotion, the progress of the animalcule being never very rapid.
The cuticle or ectoplasmic layer is composed of two distinct elements, the one external,
in which the prolongation of the cilia in the form of bacilli may be traced, while the
inner one is composed of transparent and apparently absolutely amorphous sarcode.
The cuticle is entirely destitute of contractility, the animalcule consequently being
unable to alter its form spontaneously. It is at the same time highly flexible and
elastic, allowing the body to become bent and to immediately regain its normal
contour on and after contact with external objects. The central endoplasm is com-
posed of clear liquid sarcode, having a peripheral layer of large opaque granules.
The nucleus or endoplast is free in the general cavity of the body, and is shifted
with the movements of the body from one extremity to the other. If a fresh endo-
plast, through rupture of the body, is brought in direct contact with the water, its
substance contracts, leaving, as in many other Infusoria, a fine, amorphous, superficial
membrane. The sinuous, canal-like, contractile vesicle, according to Maupas, is
provided with distinct walls — a feature which, if correctly recorded, distinguishes it
from the structure bearing the same name found in any other Infusorium — and com-
municates with the outer water by means of seven or eight lineally disposed,
clearly visible oval pores. The species propagates by multiple transverse segmentation.
The first stage of the reproductive process is accomplished through the appearance
of a clear band across the centre of the body. The endoplast, now occupying a
central position, and also the contractile vesicle, divides in two, and a constriction,
following the course of the clear band, separates the body into two equal halves,
which nevertheless remain organically united. This operation is repeated first
across the centre of each previously segmented moiety, producing four equal-sized
segments or quarters, and then again across the middle of each of these four new
subdivisions, thus producing an aggregate of eight equal-sized segments, which
ultimately become detached from each other, after the manner of the proglottids or
zoonites of a Cestoid worm. Phenomena closely coinciding with these just recorded
of Haptophrya gigantea have been already related of Anoplophrya prolifera. In this
last instance, however, it is only the posterior half of the body which undergoes
multiple segmentation.

M. Certes' later investigations, while generally confirming the account given by
M. Maupas, have elicited some additional points of interest. It is more especially
noteworthy that he declares the anterior sucker-like organ to be, if not a true mouth,
at least an organ sui generis, wherein the first acts of nutrition are localized. The
thickness of the external cuticle added to the clear layer which separates it from the
internal body-mass, he considers sufficient to preclude all possibility of the pheno-
menon of endosmosis, though, on the other hand, he is inclined to believe that the
imbibition of fluid nutriment may take place through the thinner walls of the adhesive
disc. Upon these grounds M. Certes regards Haptophrya gigantea as supplying a
bond of union between the more typical entirely mouthless Opalinidae and the
ordinary stomatode Ciliata.

Supplementary Species.

An animalcule closely resembling Haptophrya gigantea in external contour was
obtained by M. R. Blanchard, in the year 1878, from the intestine of an Alpine
Triton. On examining preserved examples, M. Certes reports that they differ from

GENUS HOPLITOPHRYA. 571

the first-named species in the contour of the sucker, which is horseshoe-shaped, or
presents the aspect merely of an oval depression armed with very strong cilia. The
cuticular surface is further destitute of the longitudinal striations that form so con-
spicuous a feature in H. gigantea. The title of Haptophrya tritonis is proposed by
M. Certes for the distinction of this apparent new species.

The animalcule described by Dr. E. Evarts * under the name of Opalina disco-
glossi, and obtained by him at Naples from the intestine of Discoglossus pictus, is
evidently referable to the genus Haptophrya. While differing somewhat in general
form from H. gigantea, it agrees with that species in size, in its possession of a
sucking-disc, single endoplast, and canal-like contractile vesicle, as also in the
phenomena of reproduction.

GENUS IV. HOPLITOPHRYA, Stein.

Animalcules mouthless, ovate or elongate, entirely ciliate, developing on
the ventral surface, towards the anterior extremity, a corneous, keel-like
band or one or more horny hooks, by which they are enabled to attach
themselves to the intestinal wall of their selected host ; endoplast and
contractile vesicle conspicuously developed. Entirely endoparasitic.

Hoplitophrya lumbrici, Duj. sp. PL. XXVI. FIG. 15.

Body elongate-ovate, somewhat flattened ; armature consisting of a
single bifid, horny hook, which is developed on the ventral surface near the
anterior extremity; endoplast band-like, axial, extending through nearly
the entire length of the body; contractile vesicles numerous, spherical,
forming an irregular line along each lateral border. Length 1-144" to
1-108". Dividing by sub-even transverse fission.

HAB. — Intestine of the common earth-worm, Lumbricus terrestris.

Stein has proposed to confer upon this animalcule the title of Hoplitophrya
armata, but since he himself acknowledges its identity with the previously described
Opalina lumbrid of Dujardin, it is desirable that the earlier applied specific name
should be retained. It would, as suggested by Stein, seem to be by no means
improbable that the Anoplophrya (Leucophrys) striata of Dujardin, tenanting the same
host, represents an immature condition only of the present type.

Hoplitophrya uncinata, Schultze sp.

Body ovoid, ventral uncini two in number of unequal length, developed
one on each side of the median line, towards the anterior extremity of the
body ; contractile vesicle elongate, canal-like ; endoplast band-like, axial.
Length 1-120". Inhabiting various marine Planarians.

According to Max Schultze this animalcule, first described by him under the
title of Opalina uncinata, inhabits only Planaria ulvce : it has more recently, however,
been found by Claparede and Lachmann abundantly infesting a member of the genus
Proceros.

Hoplitophrya falcifera, Stein.

Body slightly flattened, sometimes shortly ovate, sometimes triangular,
widest posteriorly, the length rarely exceeding the greatest breadth ;

* ' Tijds. nederl. dierk. Vereeniging,' Bd. iv., 1879.

572 ORDER HOL O TRICHA.

prehensile apparatus corneous, hammer-shaped, somewhat resembling that
of H. armata, but eccentric, and situated towards the right lateral border of
the ventral surface ; the stem or shaft of this hammer-like structure fastened
to the cuticula in a line parallel with the adjoining margin ; its thickened
anterior end produced outwards and at right angles as a stout, recurved,
pointed hook, a second slender, horny prolongation, which is recurved and
continued down and parallel with the left-hand border, being fastened
to it, produced from the same thickened distal extremity of the handle-like
portion ; the cuticular interspace between the stem of the hook and the
adherent recurved prolongation obliquely furrowed from the front and right
towards the posterior and left, these furrows further continued as fine longi-
tudinal striae over the remaining dorsal and ventral cuticular surfaces ; a row
of contractile vesicles developed along both the right and left-hand borders ;
endoplast almost as long as the body, cord-like, disposed longitudinally
towards the right body-half, its anterior end curved more or less towards
the left ; on the right side, a little behind the centre of the endoplast, is
attached a small oval endoplastule. Length 1-240".
HAB. — Intestinal tract of Lumbricus anatomicus.

As many as fifteen examples of this animalcule were found by Stein * in company
with several specimens of Anoplophrya striata, his A. lumbrici, within a single specimen
of the above-named annelid ; the occurrence of an exteriorly developed endoplastule
or nucleolus has not so far been recorded in connection with any other member
of the Opalinidae.

Hoplitophrya pungens, Stein.

Body elongate-clavate, somewhat flattened, widest anteriorly ; a trans-
versely placed, arcuate, or obtusely-angled horny band, the centre of which
is produced forward as a slightly projecting spine, developed immediately
behind the centre of the anterior border; endoplast band-like, longitudi-
nally placed ; contractile vesicles numerous, arranged lineally along the
right and left borders of the body. Dimensions unrecorded. Multiplication
as in H. secans.

HAB. — Intestinal tract of Scenuris variegata.

Hoplitophrya secans, Stein.

Body elongate, band-like, slightly widest and rounded anteriorly, a
horny keel-like band, widest in front and tapering posteriorly, developed
on the ventral surface from the anterior end backwards to the median line;
contractile vesicles numerous, located close to one another along the centre
of the dorsal line ; endoplast cord-like, axial, thicker than in H. securiformis.
Dimensions unrecorded.

HAB. — Intestinal canal of Lumbriculus variegatus, and Enchytrmts
vermicularis.

When multiplying by transverse fission this species does not' divide into two
equal portions, but through the constriction and subsequent separation off of small

* ' Sitzungsberichte d. konigl. Bohmischen Ges. d. Wiss.,' 1861.

GENUS HOPLITOPHRYA. 573

fragments of the posterior region of the body ; as in many Anoplophrya, the hinder
of the two zooids may be four or five times smaller than the anterior one and
resembles at first sight a bud-development from the same.

Hoplitophrya securiformis, Stein.

Body small, elongate-ovate, flattened and widest anteriorly ; the front
margin obliquely truncate, often curved to one side and hatchet-shaped •
the anterior region of the ventral surface bearing a slender horny band,
which is bent abruptly posteriorly and extends backwards to the centre of
the right-hand margin ; contractile vesicles four or five in number, disposed
in a line along the left-hand border ; endoplast slender and cord-like, nearly
equalling the body in length. Dimensions unrecorded, but smaller than
H. secans.

HAB. — Intestinal tract of Lumbriculus variegatus.

Hoplitophrya recurva, Clap. & Lach. sp. PL. XXVI. FIG. 22.

Body elongate-ovate, rounded and widest posteriorly ; the anterior ex-
tremity pointed, curved to one side, its ventral face bearing a single
corneous uncinus ; contractile vesicle elongate, sinuous, extending nearly the
entire length of the body ; endoplast ovate, posteriorly situated. Length
1-125".

HAB. — Marine, within the intestinal cavity of Planaria limacina:
Norwegian coast.

As many as thirty or forty zooids of this species were observed by Claparede and
Lachmann tenanting a single example of the above-named marine Planarian. It
was originally described by these authorities under the name of Opalina recurva.

Addendum to Opalinida.

The organisms described by Claparede under the name of Pachydermon
acuminatum, found in company with Anoplophrya within the seminal receptacles of
Clitcllio arenarius, and supposed to most closely resemble Opalinidas with a distinct
and thickened cortical layer, are determined by Professor E. Ray Lankester * to be
rope-like aggregations of seminal cells.

Order II. HETEROTRICHA, Stein.

Animalcules free-swimming or attached, naked or loricate, entirely
ciliate; cilia forming two widely distinct systems, those of the general
cuticular surface short and fine, those pertaining to the oral region of much
larger size, cirrose, and constituting a linear or more or less spiral or
circular adoral or peristomal series ; the cortical layer usually highly differ-
entiated, and enclosing an even, parallel series of longitudinally disposed
muscular fibrillae.

* " Remarks on Opalina," 'Quarterly Microscopical Journal,' 1870.

574 ORDER HE TERO TRICHA .

The order of the Heterotricha includes by far the largest known representatives
of the Infusoria, many of its members being not only individually visible to the un-
aided eye, but in certain cases, as in the genera Stentor and Spirostomum, attaining a
magnitude in their extended state ranging from the one-twentieth to as much as the
one-twelfth, or even the one-sixth of an English inch. Although the large com-
parative size of the adoral cilia or cirri and presence of conspicuously developed
muscular fibrillae in the cortical layer serve to distinguish the members of this order
from the more ordinary representatives of the Holotricha, the two groups are separated
from each other by but a narrow line of demarcation. In a number of the animal-
cules referred to the Holotrichous group even by Stein himself the adoral cilia are of
considerably larger calibre than those of the general cuticular surface ; while in many
of these again, including notably the Opalinidse, the cortical layer presents a closely
parallel fibrillate structure. The Holotrichous genera Panophrys, Cydotricha, Lembus,
and Pleuronema have been already referred to as most completely bridging over
these two orders. Although including in the Heterotricha all those genera which
were originally relegated to it by Stein, it has been considered desirable in this
volume to add to them Tintinnus and its allies, hitherto placed by that authority
with the Peritricha, but from which they must necessarily be disassociated on
account of the ciliation of their cuticular surface. Upon corresponding grounds
also the generic types Trichodinopsis, Calceolus, and Codonella demand a similar
position among the Heterotricha, each of these, however, differing so essentially
among themselves as to necessitate the institution of separate family groups for
their reception. Taken as a whole, the various generic groups from Tintinnus
onwards in the accompanying tabular view may be said to indicate the line of
deviation from the Heterotricha towards the more highly organized order of the
Peritricha, from certain of which, excepting for the presence of cilia on the general
cuticular surface, they are scarcely to be distinguished. In addition to the affinities
of the Heterotricha with the two groups of the Holotricha and Peritricha, just
indicated, it will be found that types are not wanting to bring them in close
relationship with the remaining order of the Hypotricha also. This affinity is more
especially marked in the genus Condylostoma and its allies, in which, as pointed
out by Stein, the peristome-neld and adoral fringe of cilia are scarcely distinguish-
able from what obtains among the typical Hypotricha, as represented by the genus
Oxytricha.

An analytical key to the families and genera of the Order Heterotricha is here-
with subjoined.

Fam. I. BURSARIAD-ffi, Stein.

Animalcules free-swimming, persistent in shape, more or less oval, often
considerably flattened ; peristome-field excavate, extending obliquely back-
wards from the frontal border, widest anteriorly, the oral aperture situated
in the posterior and narrowest confines of this region, frequently followed
by a well-developed pharyngeal passage ; larger adoral cilia developed in a
straight or oblique line on the left-hand margin of the peristome only,
not encircling the mouth in a spiral manner ; anal aperture posteriorly
situated ; no undulating membrane.

GENUS I. BURSARIA, Miiller.

Animalcules free-swimming, broadly ovate, somewhat flattened on one
side, anteriorly truncate; peristome-field pocket-shaped, deeply excavate,
situated obliquely on the anterior half of the body, having a broad oral fossa
in front, and a cleft-like lateral fissure, which extends from the left corner

CILIA TA-HETERO TRICHA.

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FAMILIES AND

FAMILY.

/" I. BURSARIAD^E.
Animalcules free-swimming, ad-
) oral cilia confined to the left border

j of the peristome, not enclosing the i
mouth in a spiral manner ; no un-
^ dulating membrane.

f

II. SPIROSTOMID.E. \
Animalcules free-swimming, peri-
stome and adoral fringe confined to
the ventral surface ; anal aperture 1
postero- terminal. J

III. STENTORID^E. \

Animalcules permanently or tem-
porarily adherent ; peristome and
adoral cilia enclosing the entire 1
funnel-shaped or variously expanded
frontal border. J

IV. TlNTINNOD^E. 1
Animalcules ovate or pyriform,
adoral cilia surrounding the ante- '
rior extremity in a simply circular 1
manner.

V. TRICHODINOPSID^;. 1
Animalcules illoricate, free-swim- |
ming, the proximal end adhesive, 1
acetabuliform.

VI. CODONELLIDJE.
Animalcules loricate, free-swim-
ming, oral cilia forming two circlets, ,
those of the outer circle attenuate,
tentaculiform. J

VII. CALCEOLID^E. \

Animalcules free-swimming, pyri-
form, with one or more annular
grooves and corresponding girdles
of larger cirrose cilia ; oral aperture
k ventral. ,

M| 5

.288-

576 ORDER HE TERO TRICHA.

of the contour border to the middle of the ventral side ; no tremulous flap ;
pharynx very long, funicular, bent towards the left, and forming an
immediate continuation of the peristome excavation ; adoral ciliary wreath
very broad, much concealed, lying completely within the peristome cleft ;
the cilia of general surface very fine, disposed in longitudinal rows ; anal
aperture postero-terminal ; endoplast band-like, curved or sinuous ; con-
tractile vesicles distinct, usually multiple. Inhabiting fresh water.

By writers previous to the time of Stein and Claparede and Lachmann the
genus Bursaria has been made to include a vast number of widely diverse infusorial
forms, now distributed, with one or two exceptions, among the genera Plagiotoma,
Nyctotherus, Leucophrys, Ophryoglena, Balantidium, Paramcecium, and Ofalina. It
thus happens that out of a score or more of animalcules associated with the title
of Bursaria by Ehrenberg, and included in Pritchard's ' Infusoria,' one- species
only, the Bursaria truncatella of Miiller, is now left to represent the genus.

Bursaria truncatella, Miiller. PL. XXIX. FIGS, i AND 2.
Body broadly ovate, purse or sac-shaped, the ventral border flattened,
the dorsal one convex, scarcely half as long again as broad, widest pos-
teriorly, narrowed slightly at the truncate anterior extremity, the frontal
angles rounded, the margin of the right side convex, usually longer than
that of the left, the margin of the shorter left side slightly concave ; endo-
plast band-like, flexuose; contractile vesicles minute, spherical, many in
number, distributed throughout the substance of the cortex. Length 'of
body 1-48" to 1-36". HAB. — Pond and marsh water.

As originally figured by Ehrenberg, this species is represented as possessing but
one large terminal contractile vesicle, and Claparede and Lachmann, adopting the
view of Lieberkuhn, have accordingly considered it desirable to recognize the many-
vesicled form as a distinct species under the title of Bursaria decora. It is main-
tained, however, by Stein that in all details of form and structure the two animal-
cules so essentially agree with each other that their separation as two distinct species
cannot be recognized. Supposed embryos of this animalcule, PI. XXIX. Fig. 2,
were observed by Stein to the number of from thirty to as many as two hundred
inside a single adult. These embryos were simply ovate, clothed all over with
fine cilia, a minute tubular prominence being developed at the anterior extremity.
The accredited parent Bursaria, in certain of these instances, was observed to be in
a quiescent condition, perfectly ovate in form, and having all trace of the peristome
and oral fossa obliterated. Singularly to remark, however, the endoplast was still
present in its characteristic band-like form ; this last-named circumstance justifies
a doubt as to whether or not these so-called embryos were parasitic organisms, and
more especially since their further development into typical Bursaria was not traced
by Stein. From Condylostoma stagnalis and Leucophrys patula, which at first
sight, perhaps, presents a considerable resemblance to it, Bursaria truncatella may
be readily distinguished by the extraordinary development of the pocket-like oral
fossa. The present species is apparently by no means a cosmopolitan form, hut
where found usually occurs in considerable abundance. The author has recently
obtained this fine animalcule through Mr. Thomas Bolton from the neighbourhoods
of Stourbridge and Birmingham. It was observed of the examples from the last-
named locality that the ordinary contour exhibited was compressed, curved, and
elongate to an extent that clearly assimilated them to the characteristic shape of
Leucophrys patula, as delineated at PI. XXIX. Fig. 18. The smaller Bursaria vorti-
cella of Ehrenberg is held by Stein to be identical with the younger and immature
conditions of B. truncatella.

GENUS BA LANTIDIUM. 577

GENUS II. BALANTIDIUM, C & L.

Animalcules free-swimming, ovate or fusiform, subcylindrical, slightly
truncate in front; peristome-field but little excavate, straight, somewhat
triangular, widest anteriorly, terminating posteriorly towards the centre
of the ventral surface in a narrow cleft, the left border only bearing the
large adoral cilia ; pharynx absent or rudimentary ; anal aperture postero-
terminal ; endoplast ovate or linear ; contractile vesicles usually numerous.
Occurring mostly as parasites within the intestinal viscera of vertebrate
animals.

The Bursaria entozoon of Ehrenberg is made the type of this genus by Claparede
and Lachmann, to which Stein has added three new forms. These are to be
distinguished from Bursaria proper by the more simple and non-excavate character
of the peristomal area, and by the absence of the extensively developed pharynx,
which constitutes so essential a characteristic of the single representative of the last-
named genus.

Balantidium entozoon, Ehr. sp. PL. XXIX. FIG. 3.

Body ovate or pyriform, narrowest anteriorly, from one and a half to
twice as long as broad, the narrower anterior end somewhat curved to one
side, obliquely truncate ; peristome-field extending backwards to the
centre of the ventral surface, almost median, but inclining obliquely slightly
towards the right, of considerable width in front, forming a short narrow
throat posteriorly ; contractile vesicles usually four in number, two situated
on either side, often rosette-shaped ; endoplast sausage-shaped, curved, with
a distinct, subcentrally attached endoplastule. Length 1-240" to 1-40".

HAD. — Parasitic within the rectum of the common and edible frogs,
Rana temporaria et esculenta.

This species typifies one of the earliest known infusorial forms, it corresponding
in part with the "Animalcula in stercore Ranarum" described and figured by
Leeuwenhoek in the year 1722. In addition to its identity with the Bursaria
entozoon of Ehrenberg, it is now recognized as synonymous also with the Bursaria
nudetts of that authority, with the Paramecium nucleus of Schrank, and with the
Leucophrys entozoon of Stein. Experiments made by the last-named investigator
elicited the fact that this animalcule cannot survive more than a day or two's
isolation in ordinary fresh water, unless this medium is mingled with the co'ntents
of the frog's intestine, thus proving the creature's essentially parasitic nature.

Balantidium elongatum, Stein.

Body elongate-fusiform, subcylindrical, from two to two and a half
times as long as broad, the anterior end pointed or slightly obliquely
truncate ; peristome-field median, narrow, cleft-like, not extending back-
wards beyond a quarter of the length of the entire body ; no distinct
pharynx ; contractile vesicles two in number, situated medially towards
the posterior extremity of the ventral surface; endoplast ovate.
Length 1-120" to 1-84".

HAB. — The intestinal canal of Triton taniatus and Rana esculenta.

VOL. II. I

578 ORDER HE TERO TRIG HA .

Balantidium coli, Malmsten sp. PL. XXIX FIGS. 16 AND 17.

Body shortly oval, almost egg-shaped, subcylindrical, from one and a
half times to twice as long as broad, the anterior extremity to a small extent
obliquely truncate ; peristome-field very short, median, triangular, curved
towards the right ; no distinct pharynx ; endoplast elongate-ovate ; con-
tractile vesicles two in number, located medianly and posteriorly towards
the right side of the ventral surface. Length 1-360" to 1-168."

HAB. — Rectum of swine and of the human subject.

Attention was first directed in a notable manner to this animalcule by Professor
P. H. Malmsten, of Stockholm, who described it in Virchow's ' Archiv fur Patho-
-logische Anatomic' in the year 1857, under the title of Parametium (?) coli. The
specimens forming the subject of this description were discovered in profusion
within the faecal evacuations of two patients admitted to the Stockholm Hospital,
both suffering from chronic diarrhoea, and one of whom succumbed to this disease.
A post-mortem investigation showed the surface of the large intestine to be con-
siderably ulcerated, and its cavity above the sigmoidal flexure to be filled with a
pungent, fetid liquid. A number of these Balantidia were found both in this
liquid and in the neighbourhood of the ulcerated portions, but not in such abundance
as in connection with the mucus-lining of the more healthy parts of the caecum and
vermiform appendage. This circumstance renders it doubtful whether or not these
animalcules were the cause, or merely an accompaniment of the disease in question,
the subject being at all events well worthy of further investigation. No trace of
these Infusoria was detected above the valve of the colon. This endoparasitic
species has been since found by Stein in great abundance in the rectum and faecal
evacuations of the common hog.

Balantidium duodeni, Stein.

Body shortly ovate or broadly almond-shaped, scarcely longer than
broad, considerably flattened ; the ventral surface much less convex than
the dorsal one, and from which in profile it seems separated by a line or
angle of demarcation ; peristome-field narrow, cleft-like, produced on the
right side nearly as far as the centre of the lateral line ; no distinct pha-
ryngeal prolongation ; endoplast ovate ; contractile vesicle single, situated
towards the right-hand side of the posterior extremity. Length 1-288" to
1-192". HAB. — The duodenum of the edible frog, Rana esculenta.

This species, while found enjoying the hospitality of the same amphibian as
Balantidium entozoon, is reported by Stein to be entirely confined to the mid-intestine
or duodenum of that host, which position it monopolizes to the exclusion of all
other infusorial forms. The general surface ciliation of this animalcule is highly
characteristic, being longer and finer than in the species previously described,
mostly directed forwards, and having a tendency to group itself, as with Conchophthirus
and many Opalinidse, into even, longitudinally disposed, pencil-like tufts. Multipli-
cation by transverse fission has been frequently observed.

Balantidium medusarum, Mereschk. PL. XXXII. FIG. 22

Body soft and flexible, variable in form, more or less ovate or sub-
cylindrical, almost two and a half times as long as broad, the posterior
extremity rounded, the anterior one from left to right obliquely truncate ;
peristome-field produced backwards in the median line to the centre of the

GENUS NYCTOTHERUS. 579

body, its left-hand border bearing an even row of powerful adoral cilia ;
cuticular surface with well-marked longitudinal striations, and frequently with
finer and less conspicuous interconnecting transverse striae ; cuticular cilia
very long, fine, and widely scattered, presenting the aspect of fine setae ; con-
tractile vesicles one or two in number, situated near the posterior extremity ;
endoplast ovate or subspheroidal, centrally located. Length 1-600".

HAB. — Salt water : White Sea (Mereschkowsky), within the alimentary
and radial canals of various small Medusas (Eucope and Bougainvillea) and
also in certain marine worms (Brada).

This species, which is referred with some doubt to the present genus by its
discoverer, is remarkable for the great length and setose character of the cuticular
cilia ; these appendages, though much less thickly distributed, would appear to
correspond closely with the similarly long, fine, setose cilia of the Holotrichous
genera Cydidium and Pleuronema. Probably it will be found desirable to institute a
new generic title for its reception.

GENUS III. NYCTOTHERUS, Leidy.

Animalcules free-swimming, ovate or bean-shaped, more or less com-
pressed, the dorsal border convex, the ventral one usually bent inwards
centrally ; peristome-field excavate, commencing a little behind the apical
extremity, continued in a cleft-like manner on the ventral side to the centre
of the body, and there produced backwards and inwards to meet the well-
developed ciliated pharynx ; the left border of the peristome only bearing
the adoral cilia; anal aperture permanently conspicuous as a chink-like
fissure, and continuous with a short tubular rectal passage ; contractile
vesicle usually single, subterminal ; endoplast more or less ovate, situated
mesially in advance of the pharyngeal cleft. Occurring as parasites within
the intestinal cavities of Amphibia and Invertebrata.

This genus was founded by Professor Leidy* for the reception of the form
hereafter described under the title of Nyctotherus velox, to which various
supplementary species have since been added. From Plagiotoma, which it to a
considerable extent resembles, it is to be distinguished by the excavate character
of the peristome-field, and by the highly developed, permanently conspicuous anal
passage. In connection with this last-named structural differentiation Nyctothenis,
indeed, stands almost alone among the entire infusorial series. As will be at
once recognized it needs the intercalation of but a short continuation inwards of the
inceptive and excretory passages to produce as physiologically complete an alimen-
tary tract as is possessed by the Proctuchous Turbellaria and other lower Metazoa.
It is a somewhat remarkable circumstance that an Infusorium provided with so com-
plex an alimentary organization should, as in the case of Nyclotherus cordiformis,
subsist side by side with the Holotrichous Opalinidas, in which all trace even of an
inceptive aperture has either remained undeveloped, or become completely
obliterated. It might be suggested, in this connection, that while these Holotricha
have adapted themselves, like babes in evolution, to an entirely fluid nutriment,
Nyctotherus has retained and further developed a partiality for the more solid meats
of the rich feasting grounds among which it delights to rove.

It is desirable to remark that that aspect in Nyctotherus and other allied genera

' Proc. Acarl. Nat. Sci., Philadelphia,' 1849.

I 2

580 ORDER HETEROTRICHA.

is referred to in this volume as the ventral one upon which the oral aperture
debouches. Stein, on the contrary, in his figures and descriptions of these animal-
cules, distinguishes by such title the region lying to the right-hand of this aperture.

Nyctotherus cordiformis, Stein. PL. XXIX. FIG. 4.

Body bean- or kidney-shaped in profile, somewhat pointed anteriorly,
much compressed, the breadth equal to two-thirds or three-quarters of the
total length ; pharyngeal cleft considerably surpassing in length the preced-
ing peristome-border, produced inwards to the centre of the body and then
recurved towards the ventral aspect ; the widened entrance or vestibulum
to the pharynx bearing on its lower edge a single long, stiff seta; striae
of the cuticular surface forming two convergent parallel systems, which meet
one another anteriorly, those forming the dorsal series occupying the larger
area ; endoplast elongate-oval, with a minute centrally attached endo-
plastule ; contractile vesicle single, postero-terminal. Length of body
1-168" to 1-108".

HAB. — Parasitic within the intestinal viscera of frogs and toads.

Nyctotherus ovalis, Leidy.

Body broadly egg-shaped or shortly pyriform, often scarcely longer than
broad, the anterior extremity rounded ; pharyngeal cleft scarcely as long
as the peristome border, produced obliquely inwards to the centre of the
body, bearing no supplementary vestibular bristle ; cuticular strise forming
a single series, disposed in the same straight line from the apical to the
posterior extremity ; the anterior half of the body usually containing a
well-defined granular interspace ; endoplast elongate-oval, curved ; no
distinct endoplastule ; contractile vesicle single, subterminal. Length of
body 1-384" to 1-72".

HAB. — Within the intestine of orthopterous insects, including various
species of Blatta and Gryllotdlpa.

This species is identical with the Plagiotoma blattarum of Claparede and
Lachmann, and also of Stein in his earlier works.

Nyctotherus gyoeryanus, Stein. PL. XXXII. FIGS. 20 AND 21.

Body oval or obovate, truncate or slightly kidney-shaped as seen in,
profile, moderately compressed ; pharynx equal in length to the peristome,
directed abruptly and obliquely inwards, having no supplementary vestibular
bristle ; cuticular striae or fibrillae of the sinistral region forming two
obliquely convergent, distinct fasciae, those of the dextral and ventral
surface forming a single oblique parallel series ; a clearly defined, granular,
kernel-like interspace enclosed at the anterior extremity; endoplast
elongate-fusiform ; contractile vesicle single, postero-terminal. Length
1-288" to 1-108".

HAB. — The intestinal canal of Hydrophilus pisceus, and other water
beetles.

GENUS ME TOP US. 581

Nyctotherus velox, Leidy. PL. XXIX. FIG. 5.

Body ovate, white and translucent, the front border obtusely rounded,
posteriorly somewhat angular and pointed, enclosing an anterior granular
trapezoidal area ; peristome directed abruptly downwards and inwards ;
pharyngeal cleft not equalling the peristome in length ; anal aperture con-
spicuous, postero-terminal, presenting the form of an inwards and down-
wardly produced tubular cleft; cuticular striae forming a single uninter-
rupted longitudinal series; contractile vesicle large, spherical, postero-
terminal; endoplast ovate. Length 1-254" to 1-180".

HAB. — -Intestinal tract of Julus marginatus.

Thousands of examples of this animalcule are reported by Professor Leidy as
being frequently found infesting the intestinal canal of a single individual of the
above-named American myriapod. A form apparently identical with this species,
has been more recently obtained by D'Udekem from the European Julus terrestris.
While the contour of the peristome in N. velox accords most nearly with that of
Nyctotherus gyoeryanus, the cuticular striation and proportionate size of the pharyngeal
cleft resemble that of N. ovalis.

GENUS IV. METOPUS, C. & L.

Animalcules free-swimming, highly elastic and changeable in shape,
normally elongate-oval or fusiform, rounded at both extremities, cylindrical
or only slightly flattened ; the anterior portion usually twisted obliquely
towards and overlapping the left side of the ventral surface, sharply sepa-
rated from the posterior portion ; peristome-field furrow-like, commencing
on the left side at a little distance from the anterior extremity, produced
obliquely downwards towards the right in the groove formed by the oblique
curvature of the body, and terminating in a short pharynx at about, or
shortly past, the median line ; on the contraction or shortening of the body,
the peristome with the pharynx, for the time, describes a complete spiral
circuit, the animalcules presenting in this condition a totally different
aspect ; anal aperture postero-terminal ; contractile vesicle single, posteriorly
located. Inhabiting salt and fresh water.

The singular spiral twist of the body exhibited by the animalcule of this genus
seems to be to some extent foreshadowed by those species of the genus Nyctotherus
in which the muscular fibrillae of the antero-posterior cuticular surface take opposite
directions, such peculiarity being most prominently exemplified in the form
described under the title of N. gyoeryanus.

Metopus sigmoides, Mull. sp. PL. XXIX. FIGS. 6-9.

Body in its normal aspect cylindro-fusiform, three to three and a half
times as long as broad, the two extremities rounded, the anterior one
twisted on the ventral aspect obliquely towards the left ; peristome-field
produced backwards to the centre of the body, and then continued inwards
as a short, tubular pharynx, a tuft of longer cilia developed at the posterior
extremity ; endoplast ovate, situated near the termination of the peristome,

582 ORDER HETEROTRICHA.

associated with a minute centrally attached endoplastule ; contractile vesicle
of large size, occupying a median position adjacent to the posterior extre-
mity. Length 1-300" to 1-96".

HAB. — Mostly fresh water, among Lemna trisulca and other aquatic
plants, rarely in sea water.

Although receiving both its characteristic generic and specific title at the hands
of Claparede and Lachmann, this singular species had been already observed by
several of the earlier writers, being first figured indeed by O. F. Miiller*as a species
of Trichoda, and also as an unknown form by Max Perty. Stein, who in his
fine monograph of the Heterotricha gives the most exhaustive description and
illustrations of this type, represents it as assuming at will three very distinct and
highly characteristic aspects. The first and most normal of these (PI. XXIX. Fig. 6)
accords with that given in the foregoing diagnosis, and in which the animalcule is so
extended that the entire length is equal to or somewhat exceeds three times the
greatest breadth, while the anterior region is twisted obliquely across the body on
the ventral side. In the second instance (PI. XXIX. Fig. 7) the body is much fore-
shortened, the length now scarcely exceeding twice the breadth, while the peristome,
with its row of larger adoral cilia, is caused by this contraction to describe a more or
less complete spire around the animalcule's body, and which in some instances is
composed of two or even three turns. The third characteristic aspect presented by
this animalcule (PI. XXIX. Fig. 8) is produced through its assumption of a com-
pletely extended and flattened shape, and in which no trace of the normal oblique
flexure of the anterior region being exhibited, its contour corresponds closely with
that of a Plagiotoma or Balantidium. It is with this form, which would appear to
represent a very distinct local variety if not a separate species, that the largest
dimensions recorded in the foregoing diagnosis are encountered. Under the name
of Strombidium polymorphum, a great variety of the protean contours assumed by this
animalcule have been figured by Dr. Ernst Eberhard in the ' Osterprogramm der
Coburger Realschule,' 1862. Among these, however, as already pointed out by Stein,
are several representations that must be undoubtedly separated from the present
type and referred to the Peritrichous form Gyrocorys oxyura. This type while
exhibiting an axial convoluted spire of adoral cilia that closely corresponds with that
of Metopus in its second described characteristic stage differs in that the finer cilia
of the general cuticular surface, which is of itself indurated instead of soft and flexible,
are entirely wanting, the posterior extremity being further supplemented by a long,
pointed, tail-like style. The frequent occurrence of these two forms in close associa-
tion with each other would seem to favour Eberhard's conjecture that Metopus may
possibly represent the earlier or larval condition of Gyrocorys, though such an antici-
pation is not supported by the result of Stein's researches. The animalcule described
by De Fromentel under the title of Metopus inflatus would appear from the very insuf-
ficient details given to correspond with M. sigmoides in that third named and rarer
condition in which the oblique flexure of the anterior region of the body is straightened
out and obliterated. The occasional occurrence of this species in salt water is
recorded by Stein. Possibly, however, such marine example belonged to the type
next described.

GENUS V. METOPIDES, Quennerstedt.

' Animalcules free-swimming, persistent in form, more or less ovate, the
anterior part twisted or folded obliquely towards the left across the
remaining portion, the groove between the two regions strongly ciliate, and
perforated at its posterior end by the oral aperture ; cilia of the general
cuticular surface fine, two or more conspicuous setae developed at the
posterior extremity.

* ' Animalc,,' tab. xxvii, figs, 7 and 8, 1786.

GENUS PLAGIOTOMA. 583

Excepting for the presence of the posterior setae, the single representative of this
genus would appear to coincide entirely vfithMetapus. Similar, though more numerous,
seta are indeed, according to Stein, possessed by Metopus in the earlier phases of its
growth.

Metopides contorta, Quenn. PL. XXXII. FIG. 18.

- Body elongate-ovate, about two and a half times as long as broad,
rounded posteriorly ; the anterior third folded obliquely to the left, across
the ventral aspect ; cuticular surface striate longitudinally, cilia long and fine,
matting together in a tuft-like manner ; posterior setae two in number ;
contractile vesicle postero-terminal. Length 1-275". HAB. — Salt water.

GENUS VI. PLAGIOTOMA, Dujardin.

Animalcules free-swimming, persistent in shape, ovate, compressed or
lamellate, the ventral margin straight, the dossal one convex ; oral aperture
situated on the ventral surface ; peristome-field extending from the
anterior extremity to the oral aperture, bearing a row of adoral cilia on the
left side only, continued inwards at the oral entrance so as to form an
obliquely directed tubular pharynx, a single long bristle protruding from
the lower border of the pharyngeal cleft ; anal aperture postero-terminal,
not conspicuous. Inhabiting the intestinal viscera of invertebrate animals.

Plagiotoma lumbrici, Duj. PL. XXIX. FIG. 10.

Body from three to four times as long as broad, compressed, lanceolate
or almond-shaped, transparent, margin of the ventral surface straight, that
of the dorsal one convex, posterior termination usually obliquely truncate ;
oral aperture situated a little way behind the centre of the ventral surface ;
pharyngeal cleft curved, produced downwards and backwards nearly to the
central axis of the body ; endoplast ribbon-like, convolute or racemose ;
contractile vesicle single, located close below the pharyngeal cleft. Length
1-192" to 1-120".

HAB. — Intestine of the common earthworm, Lumbricus terrestris.

This species is identical in part with the Paramedum compressum of Ehrenberg,
and was first noticed by Gleichen in the year 1781 under the title of the Bean-
animalcule or " Bohnenthierchen?

Fam. II. SPIROSTOMnXffi, S. K.

Animalcules free - swimming, usually more or less flattened, rarely
cylindrical, often attenuate ; peristome-field excavate, extending along the
left side of the ventral surface from the anterior extremity towards the
centre of the body, the oral aperture located in the angle formed by the
posterior border of the peristome; larger adoral cilia forming a right-
winding or dextrotropous spire, continued along the entire outer margin of
the peristome-field, or confined to the posterior portion only of this area,
the inner border of the peristome occasionally bearing an undulating
membrane ; anal aperture posteriorly situated.

584 ORDER HETEROTRICHA.

GENUS I. CONDYLOSTOMA, Dujardin.

Animalcules free-swimming, changeable in form, ovate or elongate
almost cylindrical, slightly flattened and obliquely truncate anteriorly ; the
peristome-field restricted to the anterior extremity of the body, presenting
the aspect of a harp-shaped excavation, the upper and outer or left-side
border of which bears the strong adoral cilia, while from its entire inner
or right margin is produced a flap-like undulating membrane ; endoplast
elongate, moniliform ; contractile vesicle single or multiple, sometimes
associated with elongate canal-like extensions ; anal aperture postero-
terminal. Inhabiting salt and fresh water.

Condylostoma patens, Mull. sp. PL. XXIX. FIG. 12.

Body highly elastic, elongate-elliptical or ribbon-shaped, more or less
undulate, nearly cylindrical, its length when extended equal to seven or
eight times its greatest breadth, widest posteriorly, somewhat flattened
anteriorly, slightly contracted behind the region of the peristome ;
peristome-field consisting of an irregularly triangular or harp-shaped ex-
cavation occupying an almost median position at the anterior extremity of
the ventral surface, its length equal to about from one-fifth to one-sixth of
the entire body, succeeded by a narrow tubular pharynx equal to one-half
the length of the peristome ; undulating membrane conspicuous, extending
over the whole length of the right side of the peristome-border, its width
equal to one-half of that of the peristome-field ; peristome-field unciliated,
very transparent ; cuticular striae fine, distributed equally and in parallel
longitudinal lines throughout the surface of the body ; endoplast elongate,
moniliform, located towards the right side ; contractile vesicle canal-like,
often breaking up into vesicular spaces that extend along the entire left
border of the animalcule. Length of extended body 1-72" to 1-48".

HAB. — Sea water.

This animalcule was first figured and described by O. F. Miiller as a species
of Trichoda, its present generic title being conferred upon it by Dujardin. Claparede
and Lachmann have proposed to add a new species to the genus Condylostoma
under the title of C. patulum. As shown by Stein, however, there does not appear
to be sufficient evidence to permit of this type being regarded as otherwise than
identical with one of the many protean forms assumed by C. patens,

Condylostoma stagnate, Wrz. PL. XXIX. FIG. n.

Body slightly contractile only, broadly ovate, not twice as long as
broad, rounded and widest posteriorly, the anterior border obliquely
truncate ; peristome-field broadly triangular, extending backwards through
nearly one-half of the length of the body, its right border bearing a well-
developed undulating membrane, its left one a vigorous fringe of large
adoral cilia ; longitudinal muscular fibrillae large and coarse ; contractile
vesicle presenting the form of an irregular-shaped vacuole at the posterior
extremity; endoplast elongate, moniliform. Length 125".

HAB. — Stagnant water.

GENUS BLEPHARISMA. 585

The rounded contour of this species, as first figured and described by
Wrzesniowski,* at once distinguishes it from the previously enumerated salt-water
representative of the genus. The author has recently received examples of this
animalcule from the neighbourhood of Birmingham through Mr. Thomas Bolton.

GENUS II. BLEPHARISMA, Perty.

Animalcules free-swimming, persistent in form, the anterior region
much compressed, pointed, sickle-shaped, and curved towards the 'left;
peristome-field consisting of a long, deep, fissure-like cleft situated on the
left-hand border of the body, extending to the median line of this border
and continued inwards as a short funicular pharynx ; the outer or left-hand
margin of the peristome only bearing the larger adoral cilia, a short undulat-
ing membrane protrusible from the basal portion of the right-hand margin ;
endoplast ovate or elongate ; contractile vesicle single, subterminal ; anal
aperture postero - terminal. Inhabiting fresh water, usually brightly
coloured.

The two types Blepharisma hyalinum and B. persidnum referred to this genus as
instituted by Perty, are identified by Stein as varieties only of the same form and
equivalent to the Bursaria lateritia and Loxodes cithara of Ehrenberg, these corre-
sponding again with the Plagiotoma lateritia of Claparbde and Lachmann. From
Plagiotorna the representatives of this genus are to be distinguished by the presence
of the delicate undulating membrane and by the slightly spiral instead of perfectly
straight disposition of the peristomal cilia.

Blepharisma lateritia, Ehr. sp.

Body lanceolate or almond-shaped, three or four times as long as broad ;
peristome reaching to the centre of the median line or sometimes beyond
it, the undulating membrane in profile presenting a bristle-like aspect ;
endoplast oval, situated in the anterior half of the body ; colour peach-
bloom, purple-red, or brick-red, rarely transparent. Length 1-456" to
1-120". HAB. — Fresh water.

Although individually persistent in form, the animalcules of this species vary con-
siderably in contour among themselves according to their age and stage of develop-
ment. Thus while the lancet-shaped contour with sharply-pointed extremities
represents the most normal and constant shape, it not unfrequently happens that
examples occur in which these terminations are nearly equally rounded, the animal-
cules under such conditions closely approaching the form of an almond. The
conjugation of two zooids by the application of their oral surfaces, as in Para-
mcBdum and other types, was first observed by O. F. Miiller and subsequently seen by
Stein. After such conjugation, according to the last-named authority, the endoplast
breaks up into from three or four to as many as eight spheroidal fragments, which
doubtless represent the germs of new individuals.

Blepharisma undulans, Stein. PL. XXIX, FIG. 15.

Body elongate-lanceolate, four or five times as long as broad ; the
peristome extending to one-third only of the length of the whole body ;
undulating membrane conspicuous, lamellar, occupying about one-half of

* " Infusorien aus der Umgebung von Warschau," 'Zeit. Wiss. Zool.,' Bd. xx. 1870.

586 ORDER HETEROTRICHA.

the right-hand peristome-border ; an ovate endoplast usually present in
both the anterior and posterior body-half, frequently connected by a cord-
like funiculus or commissure ; colour deep purple-red. Length 1-96" to
1-72". HAB. — Fresh water.

This species is distinguished from the preceding type by the greater length of its
body, the smaller proportionate extent of the peristome field, and the more highly-
developed undulating membrane. Stein obtained it from the neighbourhood of
Prague, and identifies it (in pars) with the Blepharisma persicum of Eberhard, but
not with the animalcule bearing that name as recorded by Perty.

GENUS III. SPIROSTOMUM, Ehrenberg.

Animalcules free-swimming, highly elastic, contractile and changeable
in shape, usually of great length in proportion to their width, cylindrical
or slightly flattened, rounded in front, truncate posteriorly ; peristome-
field elongate, extending down the left-hand side of the ventral surface as
far or farther than the middle of the body, widest at this point and continued
obliquely inwards as a short funicular oesophagus ; adoral cilia bordering
the outer or left-hand side only of the peristomal area ; no undulating
membrane ; endoplast ovate or moniliform ; contractile vesicle canal-like,
usually with a large posterior dilatation ; anal aperture postero-terminal.
Inhabiting fresh water.

Among the innumerable protean forms assumed by the representatives of this
genus, that associated with a spiral contraction upon their long axis is most frequent,
such contraction imparting to the peristome the appearance of being spirally con-
volute around the animalcule's body. In Pritchard's 'Infusoria,' ed. iv. 1861, the
possession of an undulating oral membrane has been wrongly accredited to this genus.

Spirostonmm teres, C. & L.

Body linear-fusiform, from ten to fifteen or twenty times as long as
broad, the anterior region slightly narrowest, the anterior extremity rounded
obliquely towards the left side only or in an even manner, the posterior
border truncate ; peristome-field not reaching to the centre of the body,
frequently occupying a third only of its entire length ; endoplast simple,
ovate ; contractile vesicle canal-like, extending through the entire length of
the body, usually exhibiting a conspicuous posterior dilatation. Length of
extended body 1-72" to 1-60". HAB. — Pond water among Lemn<z.

Spirostomum ambiguum, Ehr. PL. XXIX. FIGS. 13 AND 14.

Body elongate, thread-like, from twelve to sixteen times as long as
broad, nearly or entirely cylindrical, the antero-posterior extremities often
equally rounded, but the posterior one occasionally truncate ; the peristome
extending quite to the centre of the body, frequently beyond this point ;
endoplast cord-like, moniliform when fully developed ; contractile vesicle
canal-like, extending throughout the whole of the body, often much dilated
posteriorly. Length of extended body varying from 1-48" to as much as
1-12" or even 1-6". HAB. — Pond water among Lemnce.

GENUS LE UCOPHR YS. 587

This form is distinguished from the preceding by its larger size, the greater pro-
portionate development of the peristome and more elongate and composite character
of the endoplast. Stein unites in this species both the Spirostomum ambiguum and
S. virescens of Perty. The author has obtained this species in great abundance in
pond water with Lemna trisulca near St. Heliers, Jersey, its comrades being
Urocentrum turbo, Paramacium chrysalis, and Spirillum volutans ; the examples
then collected lived healthily for many weeks within the restricted limits of a wide-
mouthed bottle. Their long, filiform bodies, which exceed in length the dimensions
of any other Infusorial type, are quite conspicuous to the unassisted eye, and gleam
in the sunlight like golden threads. As shown in the accompanying figures, the
contractile vesicle in this animalcule is of very considerable relative size, its lower
extremity more particularly being often so greatly dilated as to occupy almost the
entire area of the posterior third of the body.

The Spirostomum filum of Claparede and Lachmann is regarded by Stein as
possessing insufficient characters for separate specific diagnosis.

GENUS IV. LEUCOPHRYS, Ehrenberg.

Animalcules free-swimming, persistent in form, more or less oval or
egg-shaped, the anterior extremity truncate ; peristome-field confined to
the anterior third of the ventral surface, short, and widely harp-shaped ; oral
fossa continued into the interior of the body as a long, tubular pharynx ;
the outer or left border of the peristome alone bearing the fringe of adoral
cilia, no supplementary undulating membrane ; the peristome-field covered
with short cilia, similar to those which clothe the general surface of the
body ; endoplast band-like ; contractile vesicle and anal aperture postero-
terminal. Inhabiting fresh water.

Leucophrys patula, Mull. sp. PL. XXIX. FIG. 18.

Body elongate-oval, compressed, somewhat kidney-shaped, one-half to
twice as long again as broad ; either transparent or coloured deep green
through the enclosure of chlorophyll-granules ; the two extremities slightly
curved towards the left, the anterior extremity truncate, the right-hand
corner of this frontal region angular, the opposite one rounded ; peristome-
field harp-shaped, equal in length to about one-quarter only of the entire
body ; oral aperture followed by a long tubular pharynx first produced
towards the right and then bent downwards and descending nearly to
the centre of the body ; endoplast band-like, convolute ; contractile vesicle
single, of large size, situated close to the posterior extremity, frequently
exhibiting two lateral prolongations which extend in a canal-like manner
up either side of the body. Length 1-120" to 1-72".

HAB. — Fresh water.

This species, synonymous with the Trichoda patula of O. F. Miiller, and the
Spirostomum virens and Leucophrys patula of Ehrenberg, has been the subject of
some contention among more modern investigators. Stein, regarding Ehrenberg's
Spirostomum virens as a morphologically distinct type, has conferred upon it the new
generic title of Climacostomum ; that of Leucophrys he retains only for a form which
he affirms to be identical with the Leucophrys patula originally figured by Ehrenberg
in the year 1830* and reproduced in part only in his greater work ' Die Infusions-

* ' Abhand. Berl. Akad.,' S. 42 and 76, Taf. ii., figs. 1-6, 1830.

588 ORDER HETEROTRICHA.

thiere,' 1838, and which form he further pronounces to be properly referable to the
Holotrichous order, differing from the type as here recognized only, but at the same
time essentially, in the non-possession of a fringe of larger adoral cilia or cirri.
On consulting the works cited, however, the author has been able to recognize the
presence of these differentiated cilia in every instance, such circumstance rendering
the retention of Stein's genus Climacostomum undesirable. If, as Professor Stein
maintains, an animalcule exists which agrees with his so-called Leucophrys patula
in the absence of specialized adoral cilia, such type is not referable to the Leucophrys
of Ehrenberg, and will have necessarily to be relegated, in his promised monograph
of the Holotricha, to a new genus.

In both general contour and variation of colour Leucophrys patula resembles in a
remarkable manner contracted examples of Stentor polymovphus, for which type
at a first glance it might easily be mistaken. From such, however, it is readily dis-
tinguishable by the posterior location of the anal aperture and contractile vesicle,
and by the less complete circle formed by the ciliary spire. Notwithstanding these
differences, however, the present type evidently represents a link of connection
between the families of the Stentoridae .. and Spirostomidae, uniting with the same
the characteristics of the Bursariidae as exhibited in the genus Balantidium. By
Perty, ' Kleinsten Lebensformen,' 1852, the green and colourless varieties of this
species are figured and described under the title of Bursaria virens and B. patula.

Fam. IH. STENTORIDJB, Stein.

Animalcules free-swimming or temporarily adherent, highly elastic and
contractile, more or less elongate and cylindrical ; often inhabiting, either
singly or socially, a mucilaginous or indurated sheath or lorica ; the entire
frontal border embraced by the peristome ; peristome-field circular or pro-
duced into a single central spiral or two lappet-like lateral prolongations ;
oral aperture perforating the margin or deeper confines of the peristome-
field ; larger adoral cilia or cirri describing a complete dextrotropous or
right winding spire ; anal aperture situated anteriorly immediately beneath
the peristome.

GENUS I. STENTOR, Oken.

Animalcules sedentary or freely motile at will, in the former case attach-
ing themselves by their softer adherent posterior extremity to sub-
merged aquatic objects, sometimes secreting a mucilaginous investing
sheath ; bodies highly elastic and variable in form : when swimming and
contracted, clavate, pyriform or turbinate ; when fixed and extended, trumpet-
shaped, broadly expanded anteriorly, tapering off and attenuate towards
the attached posterior extremity ; peristome describing an almost complete
circuit around the expanded anterior border, its left-hand extremity or
limb spirally involute, forming a small infundibulate or pocket-shaped fossa,
which conducts to the oral aperture, the right-hand limb free and usually
raised considerably above the opposite or left-hand one ; peristomal cilia
cirrose, very large and strong ; cilia of the cuticular surface very fine, distri-
buted in even longitudinal rows, occasionally supplemented by sparingly
scattered hair-like setae ; endoplast band-like, moniliform or rounded,
contractile vesicle usually complex, consisting of an anterior circular dila-

GENUS STENTOR. 589

tation, which gives off an horizontal annular branch which underlies the
circumference of the peristome, and a canal-like diverticulum which is con-
tinued towards the posterior extremity of the body. Increasing by oblique
fission, and by germs separated from the band-like endoplast. Inhabiting
fresh and salt water ; mostly social.

The Stentors or trumpet animalcules represent, by reason of their large
dimensions, social habits, often brilliant colouring, and cosmopolitan distribution,
not only the most familiar but the very earliest known members of their class.
The first record of the group is given by our illustrious countryman Abraham
Trembley, noted chiefly for his researches connected with the fresh-water polypes
Hydra vulgaris and H, viridis, and who, premising that these animalcules possessed
a closely identical organization, described them under the tide of the " Funnel-like
Polypes" in the 'Philosophical Transactions' for the year 1744. Three modifi-
cations of this so-called polype were observed by this early investigator, and dis-
tinguished by him under the names of the " green," " blue," and " white " varieties,
the same evidently corresponding with the three types familiar to recent investi-
gators under the respective technical appellations of Stentor polymorphus, S. caruleus,
S. Roeselii. In Mr. Baker's treatise, a few years later, ' Employment for the Micro-
scope,' 1753, these several varieties recur under the title of the "Funnel Animal,"
while one of them, S. Roeselii, is included in Linnaeus' s 'Systema Naturae,'
ed. x., 1758, under the name of Hydra stentorea. The first employment of the
generic title of Stentor was made by Oken,* 1815, who, however, included under the
same generic category the totally dissimilar organisms Ophrydium versatile and the
social Rotifer Lacinularia. By O. F. Miiller numerous representatives of the genus
are embodied in his comprehensive generic group Vorticella, Ehrenberg being the
first to secure to the genus Stentor that well-defined limitation by which, from then
up to the present time, it has been distinguished.

A noteworthy feature connected with the life-history of the representatives of this
genus is afforded by their mode of multiplication by fission, and which, instead of
taking a transverse or longitudinal direction, as in almost all other animalcules,
describes an oblique course. The phenomena accompanying this duplicative process
are of much interest, and were first recorded in a manner leaving but little to be added
by Trembley, their first discoverer. The earliest indications given of the impending
subdivision is the appearance down that side of the body of the animalcule which
accords with the one on which the peristome makes its spiral descent into the oral
aperture, and may be hence termed the ventral aspect, of a raised crest or border, which
in its earliest condition presents the appearance of an undulating membrane, but sub-
sequently splits up and forms a fringe of long cirrhate cilia similar to those which bound
the expanded peristome. Up to within a comparatively recent date this lateral crest
or fringe has been regarded as a permanent and distinctive feature of the type with
which it has been seen associated, and is cited in Pritchard's. ' Infusoria' as largely
developed in certain species, slightly only in others, while in a third series it is alto-
gether wanting. By Stein, Claparede and Lachmann, and numerous other observers,
including among our own countrymen Dr. W. Moxon,| it has, however, been clearly
demonstrated that this lateral crest represents the rudimentary condition only of
the adoral or peristomal fringe of cilia of the posteriorly-produced zooid or resultant
of the process of segmentation, and which gradually shapes itself so as to corre-
spond in form and character with that of the pre-existing anterior adoral wreath as
follows. In the first place the simple lateral crest or line of cilia becomes spirally in-
volute at its lower or proximal extremity, and, penetrating in a conical form into the
substance of the parenchyma, forms the oral aperture of the new zooid now in course
of development. This oral aperture, with its simple linear fringe of adoral cilia, may
be said at this particular stage of development to correspond closely with the normal

* ' Lehrbuch der Naturgeschichte,' Th. iii.

t 'Journal of Anatomy and Physiology,' May, 1869.

590 ORDER HETEROTRICHA.

and permanent conditions of the same structures as met with in the genus Spirosto-
mum. The anterior or distal end of the lateral fringe now begins to retreat from its
position immediately beneath the peristome of the parent zooid, and descending from
thence gradually curls round to meet the lower or oral termination. The area
enclosed within the almost conjoined extremities of this supplementary lateral fringe
represents now the peristome-neld of the newly developed zooid, and corresponds
closely in both form and size with the pre-existing anterior one. The anterior half
of the body, leaving the original adoral wreath, further elongates, and becoming
gradually thinner at its posterior extremity, permits at length of its entire separation
from the posterior half now bearing the new peristome, and swimming off selects a
new point of attachment. In this process of segmentation, as above detailed, the
usually band-like endoplast takes its share, while at an early date a second contractile
vesicle makes its appearance in close proximity to the newly-formed adoral fringe.
Various phases of the process of subdivision, as above described, commencing with
the first appearance of the second peristome, will be found at PI. XXX. Figs. 14, 22,
24, 25, and 26.

The so-called muscular or myophan layer in the members of this genus is perhaps
more conspicuously developed than in any other representative group of the Infusoria,
taking the shape of transparent thread-like fibrillai, which form a single, superficial,
closely approximated layer, and extend in an unbroken longitudinal series from the
peristome-border to the posterior extremity of the body. It is through the aid of these
highly elastic elements that the rapid and characteristic metamorphoses of external
contour are produced. A second series of hyaline fibrillse, surrounding concentrically
the peristome-border and enclosed area, acts sphincter-wise in closing up this region
when the animalcule is contracted. By not a few authorities the special contractile
or muscular properties have been wrongly accredited to the intervening coloured
and granular elements of the cortex. The posterior and adherent termination of
various species of this genus is frequently represented as provided with a special
suctorial disc. Such, however, does not exist, this region being simply abnormally
soft and plastic, permitting its free adherence to any selected object, this adhesion
being somewhat further assisted in many instances by the protrusion of fine
pseudopod-like extensions from the substance of the inner parenchyma or endo-
plasm, as represented at PI. XXX. Fig. 23.

The new generic title of Salpistes has been proposed by Dr. Strethill Wright *
for the reception of those species of Stentor which secrete gelatinous sheaths ; the
development of this accessory structure appears, however, to be so uncertain among
individuals even of the same species, that it has not been considered desirable to
adopt it in this treatise.

Stentor polymorphus, Mull. sp. PL. XXIX. FIGS. 10-20.

Body of large dimensions, the expanded anterior end when fully
extended equalling in diameter one-third of the total length, the otherwise
transparent cortical layer usually containing a rich layer of green chloro-
phyll-granules; endoplast distinct, moniliform. Length when fully ex-
panded 1-20", in contraction 1-120".

HAB. — Standing water among both living and decayed vegetation,
eminently social.

Stein embodies with this species the Stentor Miilleri of Ehrenberg, which he
pronounces to be merely a variety of S. polymorphus without the more usually
enclosed green chlorophyll-granules. The Stentor polymorphus, as figured and
described by Claparede and Lachmann, in the second volume of their ' fitudes,'
is referred by the same authority to the species next described. Although pre-

' Edinburgh Philosophical Transactions,' vol. x. 1858.

GENUS STENTOR. 591

viously known to Trembley and Baker, the present specific title of this animalcule
was conferred upon it by O. F. Miiller in the year 1773, who figured and described
it under the name of Vorticella polymorphus. Not unfrequently the colonies of this
type are found socially inhabiting a common more or less granular gelatinous
matrix somewhat resembling that of Ophrydium, but of less substantial consistence.
A fragment of such a colony, as observed by the author developed upon
the leaves and rootlets of plants of Anacharis in a small aquarium containing
axolotls kept in the Zoological Department of the British Museum in the year
1871, is represented at PL XXX. Fig. n. Fig. 16 of this plate illustrates a zooid
from the same colony as observed in the act of discharging faecal matter from the
anal aperture, the matter being shot out with such force as to alight at a consider-
able distance. At Fig. 14 an example from the same stock is delineated in which
the rudimentary peristomal fringe of a zooid preparatory to dividing by oblique
fission presents, at/r, the aspect of a laterally developed membranous crest.

Stentor Rceselii, Ehr. PL. XXX. FIGS. 22 AND 23.

Body large, the anterior extremity in full extension, scarcely equalling
in width one-quarter of the total length ; usually excreting around it and
inhabiting an independent, transparent, gelatinous sheath ; parenchyma
soft, completely transparent; cuticulum often bearing in addition to the
ordinary ciliary covering numerous fine long setae which stand out at a
right angle to the surface of the integument, these setae inserted basally
in the inner substance of the cortex and extensile or retractile at will ;
a brush-like fascicle or circlet of fine setae surrounding the adhesive posterior
extremity ; endoplast at first serpentine or ribbon-like, subsequently monili-
form. Length of extended body 1-24".

HAB. — Standing water among decaying vegetation ; mostly solitary.

According to Ehrenberg, the only difference subsisting between this species
and the preceding is represented by the form of the nucleus or endoplast, which
is described by him as moniliform in Stentor polymorphus, but simply band-like
in the present type. This distinction, however, has been shown by Stein to be
entirely unreliable, a moniliform contour being assumed likewise by the endoplast
of S. Rceselii in the more matured condition of its development. At the same time
there are other far more important points of divergence, overlooked by Ehrenberg
but pointed out by Stein, which leave no doubt as to the claim held by the present
type for independent specific recognition. Among the most prominent distinctive
features of the animalcules of the present species, as amended by Stein, may be
enumerated the almost invariable presence in connection with their fixed condition
of an independent mucilaginous lorica or investing sheath, within the cavity of
which they at once retreat upon disturbance ; the presence of the numerous scattered
hair-like setae which project from the cortex to a considerable distance beyond
the external cuticular surface, and the circlet or brush-like fascicle of finer setae at
the posterior extremity. All of these three characteristics are wanting in Stentor
polymorphus, and while, on the other hand, fine cuticular setae sometimes occur in
S. caruleus, they attain a much less considerable degree of development, and there
.is no investing sheath or tuft of caudal setae. This posterior tuft of setae would
appear to be subservient to the purpose of anchoring or attaching the animalcule
in a root-like manner to the mucilaginous substance of the bottom of its sheath,
fulfilling the part of the simply adhesive adaptation of the posterior extremity that
obtains in various other forms. The presence in this species of supplementary
cuticular setae was first observed by Lachmann in the year 1856,* and was well

* Miiller's 'Archives.'

592 ORDER HETEROTRICHA,

illustrated in the' third part of his and Claparede's joint work on the Infusoria
bearing the date of 1858. It has, however, to be observed that these authorities
regarded the four Ehrenbergian species of Stentor, viz. S. polymorphus, S. Muelleri,
S. Rceselii, and S. cczruleus, as varieties only of the same species, and consequently
associated the results of their investigations of the present type and all illustrations
of the same with the title of Stentor polymorphus. These fine hair-like setae do
not maintain a permanently extended state, but are thrust out or retracted at the
will of the animalcule, and would seem, as indicated by Stein, to possess a tactile
function and to correspond most closely in their nature with the fine pseudopodia-
like threads emitted from the adherent posterior extremity of many other species
in their fixed or sedentary conditions.

The multiplication of Stentor Rczselii through the means of internally produced
germs has been ably demonstrated by Claparede and Lachmann and also ostensibly
by Stein. By the first-named authorities, treating of this species as S. polymorphus,
it has been shown that spheroidal embryos are developed and become detached
from the band-like nucleus or endoplast. These embryos vary in diameter from
the i-yooth to the i~45oth part of an English inch, and already possess within
the body of their parent, in their earlier stage, the fine cuticular cilia only of
the general surface, supplemented by a simple spheroidal contractile vesicle ; later
on an anterior and short crescentic line of larger cilia makes its appearance, and
this ultimately develops into the extensive adoral wreath of the adult animalcule.
Claparede and Lachmann, while not successful in tracing the direct passage of the
embryos from their parent's body into the outer water, encountered numbers of
them in a free-swimming condition, and from these were able to trace every phase
of development into the parent form. Although the derivation of these spheroidal
embryos from the band-like endoplast has been first authenticated by the autho-
rities just quoted, the internal production of such embryos in connection with
Stentor ctzruleus was attested by Eckhard so long since as the year 1846,* and
was confirmed a few years later by Oscar Schmidt, both of whom witnessed what
escaped the observation of Claparede and Lachmann, viz. the actual birth of
embryos from the body of the parent. The majority of the supposed internal
embryos of Stentor Roeselii, as figured and described by Stein,t present nothing in
common with those just described, but are parasitic Acinetae referable to the genus
Sphtzrophrya. Their foreign nature is shown not only by their possession of suctorial
tentacles and general conformity with the representatives of the genus named, but
from the fact also that the endoplast within the bodies of the Stentors with which
they are associated remains intact and retains its normal band-like contour in spite
of their presence. Stein, however, records, with accompanying illustrations, his
occasional observation of a modification of the endoplast unrecorded by any other
observer, and which possibly plays an important part in the reproductive history
of this species. In these instances the normal band-like or moniliform contour
of the endoplast was entirely obliterated and its place occupied by three oval or
irregular-shaped cyst-like structures entirely filled with minute, sharply outlined,
spindle-shaped corpuscles whose longest diameter did not exceed the 1-45 6oth part
of an English inch. On slight compression these cysts, as represented at PI. XXX.
Fig. 31, were expelled through the cuticle of the parent animalcule, and bursting their
own walls released the enclosed corpuscular contents mixed with finer molecular
matters. By Stein the occurrence of this remarkable transformation of the endoplast
is dismissed as representing either a kind of fatty degeneration of that structure
or as the result of the intrusion and development within its substance of some
parasitic organism. The present author is inclined, however, to regard it as an
open question whether this does not represent one phase of an as yet imperfectly
understood method of multiplication through the medium of minute microspores,
harmonizing with similar phenomena of general occurrence among the more lowly
organized Flagellate section of the Infusoria. A circumstance slightly in favour

* Wiegman's 'Archives.' t ' Infusionsthiere,' Abth. ii. p. 254, pi. viii. figs. 3, 4, and 9.

GENUS S TEN TOR. 593

of this hypothesis is afforded by Stein's record of the occurrence of this peculiar
modification of the endoplast during the months only of September, October, and
November, or towards the approach of the winter months, when the ordinary
processes of reproduction by fission are frequently arrested.

Stentor Barretti, Barrett. PL. XXX. FIG. 21.

Body attenuate, highly extensile, its length in full extension equalling
five or six times the diameter of the expanded peristome ; peristome field
distinctly bilobate, earshaped, the larger lobe usually elevated perpen-
dicularly ; fine supplementary setose appendages developed throughout the
body portion and around the margin of the peristome ; endoplast elongate,
sinuous ; excreting and inhabiting an erect tubular gelatinous sheath, which
is usually of a light brown colour when young, but becomes darker and
more opaque as age advances. Length of extended body 1-25".

HAB. — River and pond water ; solitary.

This animalcule was first figured and described by Mr. C. A. Barrett in the
'Monthly Microscopical Journal' for April, 1870, as a "New Tube-dwelling
Stentor," this observer there taking the somewhat unusual course of associating his
own name with its specific designation. In this original description it is reported as
entirely wanting the fine body cilia which characterize the ordinary species of
Stentor, these being replaced by long hair-like setae ; the possession of a distinct
nervous system, consisting of an anteriorly located ovate body, which gave off
branches that extended down the whole length of the body, and another to the
expanded peristome, was also reported. If these two last-named structural charac-
teristics really existed, the organism described by Mr. Barrett was no Stentor, but
possessed a type of organization that precluded its retention among the Protozoa.
It was at the time, however, suspected by the author that this form represented an
imperfectly examined species closely allied to, if not identical with, Stentor Roeselii,
and in which a mucilaginous domicile and long hair-like setae are similarly developed.
This anticipation has been completely verified. The animalcule has been since met
with by a number of observers, and is included among the many interesting infusorial
types that have been supplied to the author by Mr. Thomas Bolton, such examples
furnishing the material for the illustration of the species given at PI. XXX. Fig. 21.
Through this personal examination it was soon made evident that Mr. Barrett's so-
called nervous system represented the imperfectly observed contractile vesicle with
its canal-like diverticula, while finer cilia clothing the whole body, in addition to the
hair-like setae, were speedily detected, thus reducing it to the structural formula of an
ordinary Stentor. As a trumpet animalcule, the present species is undoubtedly
closely allied to T. Roeselii, but manifests its distinctness from that type in its more
attenuate proportions, in the erect instead of horizontal comportment and distinctly
bilobate contour, of the peristome, in the more abundant development of the setose
appendages, which are produced not only from the body but from the entire circum-
ference of the peristome, and in the much firmer consistence of its mucilaginous
domicile. The examples of this species, as originally discovered by Mr. Barrett,
were found on water weeds taken from the river Thames at Moulsford, another
interesting form, referable to the genus Folliculina, apparently F. Boltoni, being
likewise found in its close vicinity.

Stentor cseruleus, Ehr.

Body large, the width of the anterior extremity or peristomal border
when fulFy extended equal to one-third of the total length ; the substance
of the intermuscular longitudinal striae coloured a more or less intense blue ;

VOL. II. K

594 ORDER HETEROTRICHA.

the fine ciliary clothing of the general surface of the integument occasionally
supplemented with a few long, fine setae, which are not, however, so con-
spicuously developed as in the two preceding species ; endoplast trans-
parent, moniliform. Length 1-192" to 1-96".
HAB. — Fresh water, on aquatic plants ; social.

As previously related,* the pigmentary substance distributed throughout the
cortex that communicates to this species its characteristic cerulean hue has been
submitted by Prof. E. Ray Lankester to spectroscopic analysis with highly inter-
esting results. Two absorption bands of remarkable intensity were clearly exhibited
whether examples were examined either singly or en masse, these differing so
essentially from the bands yielded by all other organic substances that this investigator
has conferred upon it the distinctive title of " Stentorin." Velella, an organism which
from its relatively low position in the zoological scale might have been expected to
yield a closely corresponding spectrum, was found on similar submission to the
micro- spectroscope to produce no band or bands of absorption whatever. The
spectroscopic examination of the Stentors in quantity was greatly facilitated by the
presence in the aquarium that contained them of numbers of the annelid Chceto-
gaster diaphanus, many of which had gorged themselves with the infusoria, thus
proving convenient collectors of the material required.

Stentor igneus, Ehr. PL. XXX. FIGS. 1-4.

Body of moderate size, changeable in shape to a very limited extent ;
the width of the peristome, when most fully extended, equal to about one-half
of the entire length ; internal parenchyma coloured bright green through the
presence of a rich layer of chlorophyll-granules ; the more transparent
superficial layer containing in addition finely granular pigment of an intense
scarlet hue, this being usually most abundant in the neighbourhood
of the peristome ; endoplast ovate or spherical. Length of extended body
1-72".

HAB. — Pond water, on Hottonia, Ranunculus, and other water plants ;
social.

The author obtained this species, in May 1876, in considerable abundance
attached to the leaves of the water crowfoot, Ranunculus aquatilis, taken from
a small pond on Wandsworth Common. On many occasions it was noted that the
breadth of the extended peristome in this short, trumpet-shaped animalcule con-
siderably exceeds that given by Stein, it in some instances being equal to that of its
entire height. The rich colouring of this form renders it perhaps one of the most
attractive and ornamental representatives of its genus, more especially as exhibited
with the aid of the parabolic condenser, when every tint is thrown up on the dark
background with intensified distinctness. On one occasion, in connection with the
death and disintegration of an adult example, the release was observed from its debris
of a spheroidal embryo, possessing an anterior crescent-shaped row of larger adoral
cilia and a general covering of finer ones, the germ in its entirety thus agreeing
essentially with those already described by Claparede and Lachmann in relationship
with Stentor Roeselii.

Stentor niger, Ehr.

Body of moderate size, exceedingly changeable in shape, when fully
extended nearly three times as long as broad, the surface parenchyma

* Vol. I. p. 79.

GENUS STENTOR. 595

thickly filled with minute blackish, yellow, and coffee-coloured pigment-
granules ; endoplast spherical. Length of body when extended 1-96".
HAB. — Bog water.

Stein embodies with this species the Stentor or Salpistes castaneus of Strethill
Wright, with which it seems fully to agree, with the exception that, as observed by
the last-named writer, the animalcules are in the habit of exuding an independent or
common mucilaginous investing sheath, similar to that already described of S. Rceselii.
In shape and size this form most nearly approaches S. igneus, from which, however,
it may be readily distinguished by its more plastic character and the finer granu-
lation of its parenchyma, which never contains green chlorophyll-granules, though
more especially by the greater length in comparison with its breadth, which it
exhibits in its expanded state. In this latter respect it more nearly approaches
,5". Rceselii, S. polymorp/tus, and other previously described species. Stentor niger
has been obtained by the author in some abundance in bog water at Lustleigh
Cleave on the borders of Dartmoor.

Stentor multiformis, Mull. sp. PL. XXX. FIGS. 8 AND 9.

Body moderately large, exceedingly plastic and variable in form ; ex-
panded peristome equal in width to about one-third or one-quarter of the
entire length of the body; the longitudinal intra-muscular bands of the
cortical layer coloured an intense blue or sea-green ; endoplast spherical or
ovate. Length of extended body 1-180".

HAB. — Salt water ; social.

This marine type of the genus Stentor was first described by O. F. Miiller under
the title of Vorticella multiformis ; and has since been rediscovered and investigated
by Stein. In aspect and colour it most nearly resembles the fresh-water Stentor
caruleus. It is, however, usually of much smaller size, and has at the commencement a
simply oval or spheroidal endoplast. It further exhibits a greater range of variation
in external contour than is associated with any other hitherto described type of this
genus. Among these protean diversities of outline, that depicted at PI. XXX.
Fig. 8, is, perhaps, the most remarkable, the body as a whole being in this instance
flask-shaped and produced anteriorly into a long, slender neck, with the expanded
peristome-border equal to about one-third only of the inflated posterior portion.
Under the condition of complete extension it rarely, if ever, appears to assume that
elegant trumpet form so characteristic of the ordinary species, and in which, as a
necessary consequence, the peristome-border represents the widest diameter, but is
more usually either clavate or pyriform.

Stentor auricula, S. K. PL. XXX. FIGS. 6 AND 7.

Body colourless, in extension shortly trumpet-shaped or turbinate, the
width of the expanded peristome equal to, or even exceeding, the height
of the body, the latter tapering very abruptly towards its posterior
extremity or point of attachment ; the peristomal border interrupted on
its ventral aspect by a deep cleft or sulcus which gives to the entire
structure a bilobate or auriculate appearance ; endoplast ovate, subcentral.
Length of extended body 1-130".

HAB. — Salt water.

This species is readily distinguished from all previously described forms by the
great breadth of the peristomal area in proportion to the length of the body, com-
bined with its peculiar lobate contour. In this last respect it may be said to make a

K 2

596 ORDER HETEROTRICHA.

step towards the genus Follictilaria, in which the bilobate shape of this area forms
a leading characteristic. It was discovered, in February 1877, *n some abun-
dance on the vacated polyparies of polyzoa and hydroid zoophytes obtained from
the Westminster Aquarium. Being at the time specially occupied in investigating
certain more minute flagellate Infusoria, the author unfortunately neglected to note
the form and position of the contractile vesicle or any reproductive data. The
brief description and figure here given will doubtless, however, suffice for its re-
identification and as a basis for a future more exhaustive examination.

Stentor pediculatus, From. PL. XXX. FIG. 5.

Body trumpet-shaped when extended, elongate-ovate or fusiform when
contracted ; colour clear brown ; width of the expanded peristome equal to
about one-quarter of the length of the entire body ; the area enclosed within
the peristome-border ornamented with numerous raised papillae, the
apex of each of which gives origin to several long, fine, hair-like setae ; the
posterior and adherent extremity of the body divided into six digitiform
prolongations, out of each of which four similar fine hair-like setae take
their origin. Length of extended body 1-120". HAB. — Fresh water.

Doubtful Species.

The form temporarily referred to this genus by Stein under the title of Stentor
cucullus, is synonymous with the Vorticella cucullus of Miiller. It is a large, bright
yellow, salt-water variety, so closely corresponding in shape and size with Stentor
Roeselii that Stein would have referred it without hesitation to that species had he
encountered it in fresh water. In consideration, however, of its marine habitat, he
thinks it desirable for the present to regard it as a distinct type. In the only
example observed by this authority the endoplast was long, cord-like, and of
undulating outline.

Out of the nine varieties of the genus Stentor introduced by De Fromentel in
his ' Microzoaires ' as hitherto undescribed species, his S. pediculatus appears to be
the only one with which are included characters sufficiently distinct to warrant its
recognition as a new and independent form. In all other cases the diagnoses
and figures given embody no character which can be cited as distinguishing them
from those earlier known varieties made familiar to us through the researches of
Ehrenberg, Stein, and Claparede and Lachmann, while in almost every instance the
diagnosis and figure given represent the animalcule in that free-swimming and semi-
contracted condition in which it is almost impossible to discriminate between closely
allied species. Briefly examined, the Stentor roseus of this author, with its spherical
nucleus and bright rose colour, is apparently referable to S. igneus Ehr., his
S. fuscus to S. niger Ehr., S. fimbriatus to S. Rceselii prior to fission; while his
S. aneeps, S. elegans, S. nanus, S. deformis, and S. albus appear to represent merely
young or imperfectly developed conditions of other previously established forms. Of
this, in fact, De Fromentel in several instances expresses himself prepared to admit
the probability. In all De Fromentel's figures relating to the genus Stentor, the
oral aperture is wrongly delineated as being circumscribed by a continuation of the
right-hand limb of the peristomal border.

GENUS II. FOLLICULINA, Lamarck.

Animalcules highly elastic and contractile, secreting a horny sheath or
lorica, to the inner wall of which they remain affixed by their posterior
extremity ; peristome-field embracing the entire anterior border, produced

GENUS FOLLICULINA. 597

into two more or less elongate and usually symmetrical, flattened, lappet-like
lobes or processes, the cleft between which is deepest on the oral or ventral
side ; peristomal fringe originating on the ventral side at the base of the
right-hand lobe, skirting the entire margin of the bilobate frontal border,
descending in a shortly revolute spiral manner into the oral aperture
on its arriving at its point of origin or base of the left-hand lobe ;
peristomal or adoral cilia very long, those of the general cuticular surface
exceedingly fine, disposed in even longitudinal rows ; anal aperture situated
close to the base of the left-hand peristomal lobe. Mostly inhabiting salt
water.

A somewhat subtle question of priority has arisen in connection with the
adoption of the correct title for the various members of the present genus. The
earliest efficient diagnosis of the group was given by Claparede and Lachmann in
Miiller's 'Archives' for the year 1856, and in which they bestowed upon it the title
of Freia, a name borrowed from the pages of Scandinavian mythology. This
generic title is retained in their subsequent larger work ' Etudes sur les Infusoires,'
1858-1861, the Vortuella ampulla of O. F. Miiller being there recognized and fully
described as its type form. Meanwhile Dr. Strethill Wright published in the
Edinburgh ' New Philosophical Journal ' for 1858, the account of several animalcules
possessing similar structural characteristics and, unaware of Claparede and Lach-
mann's discoveries in a similar direction, conferred upon them the generic name
of Lagotia. Two years later * Dr. Wright acknowledged the priority of Claparede
and Lachmann's title, and described a supposed new form under the title of Freia
cbstetrica. As shown, however, by Stein, in his monograph of the Heterotricha,f
the VorticeUa ampulla of O. F. Miiller, which stands as the typical representative
of this genus, was recognized as the type of a new generic group by Lamarck so
long since as the year i8i6,J and for which he proposed the name of Folliculina.
Stein furthermore points out that the name of Freia has been previously employed
by C. L. Koch in the year 1850 for the distinction of a genus of Arachnida,
but at the same time elects to retain Claparede and Lachmann's designation
on the ground of its widespread adoption. Paying strict regard to the laws of
scientific nomenclature there can be no question, however, that in a double sense the
generic name of Freia, as representing an infusorial group, must make way for
the Lamarckian one of Folliculina, which is herewith adopted. The structural
features of this genus correspond considerably with those of Stentor, the chief devia-
tion from the latter type being the abnormal bilobate development of the peristome-
border and the permanent occupation by the animalcules of a rigid sheath or lorica.
Although so widely distributed, no examples of this generic group appear to have
fallen within the cognizance of Ehrenberg, who has in consequence passed over
Miiller's VorticeUa ampulla as an imperfectly observed representative of the genus
Vaginicola, under which name it reappears in Pritchard's ' Infusoria.' A charac-
teristic feature exhibited by many of the representatives of the genus Folliculina
is afforded by the colour of the body-substance or parenchyma, which, in the
majority of instances, presents a remarkable dark bottle-green or blackish hue.
This coloration does not, as in most animalcules, result from the inception and
temporary retention of coloured food-particles, but is so intimately and inseparably
interblended with the substance of the parenchyma as to communicate its charac-
teristic tint to the externally secreted tests or loricae.

Folliculina ampulla, Mull. sp. PL. XXIX. FIGS. 21-28.
Adult sheath or lorica glaucous or sea-green, when young transparent,
more or less ovate or flask-shaped, attached laterally with the neck bent

* 'Quart. Journ. Mic. Science,' iF62. t ' Infusionsthierc,' Abth. ii., 1877.

J ' Hist, dcs Anim. sans Vert.,' torn. ii. p. 30.

598 ORDER HETEROTRICHA,

upwards ; neck short in young individuals, but becoming much prolonged
with age and usually ornamented with either horizontal or spirally ascending
annulations or with longitudinal flutings ; margin of aperture even, circular ;
animalcules similar in colour to the sheath ; peristomal lobes subequal,
attenuate, from three to six times as long as broad, their extremities more
usually bluntly, but sometimes sharply pointed. Length of body of lorica
1-380" to 1-60", neck varying from one-quarter to the entire length of the
body portion. HAB. — Salt water.

This species, representing the Vorticella ampulla of O. F. Miiller, the Folliculina
ampiilla of Lamarck, and the Freia ampulla of later writers, varies so greatly in the
form and aspect both of the lorica and contained animalcule, in accordance with its
age or local derivation, that it has received a variety of names from the several
authorities who have encountered and described it. Stein, however, who has made
this genus the subject of special study, unhesitatingly refers to different stages or
varieties of a single species all those types described under the respective titles of
Freia ampulla and F. aculeata by Claparede and Lachmann, the Lagotia viridis,
L, hyalina, and L. atro-purpurea of Strethill Wright, and the Freia americana of
Dr. Leidy. While concurring with Stein generally as to the necessity of abolish-
ing, as mere synonyms of the present type, the several nominal species above
enumerated, the author is disposed to regard as a possible distinct form Claparede's
variety illustrated by PL XXIX. Figs. 21 and 22, distinguished by the exceedingly
acuminate contour of the peristomal lobes; this at any rate may be retained
as a well-marked subspecies under the title of Folliculina ampulla van aculeata.
The Lagotia viridis of Strethill Wright accords with the normal adult condition
of the present species, while his L. hyalina, distinguished merely by the transparence
or absence of colour in the lorica and contained animalcule, is evidently the young
condition only of the same form. The Lagotia (Follicularid) atro-purpurea is admitted
by the last-named authority to be probably a mere variety only of his L. viridis,
it being found in company with that type, and differing from it only in the more
inky hue of the parenchyma and the yellowish-brown colour of the lorica.

Stein reports the occurrence of Folliculina ampulla in countless numbers upon
the spiral shells of the tubicolous annelid Spirorbis nautiloides, these themselves
being attached to the fronds of the bladder-wrack, Fucus vesiculosus. In those
older examples in which the neck-like portion of the lorica is greatly prolonged and
annulate, some approach would seem to be made towards the still more elongate
lorica of F. producta. The enclosed animalcule of this last-named type would,
however, appear to differ essentially in the narrow, ligulate shape of the peristomal
lobes. As already recorded in the 'Midland Naturalist ' for May 1880, examples
of both the short smooth-necked and attenuate annulated form of this species were
obtained by the author growing upon the single shell of a Pecten dredged from a
depth of 50 fathoms, off Falmouth, in July 1879. By an oversight, the Lagotia
(Folliculina) producta of Strethill Wright, presently described, has been there included
among the synonyms of the present type.

Folliculina elegans, C. & L. sp. PL. XXIX. FIGS. 33-35.

Lorica flask- or bottle-shaped, transparent or pale green, attached
laterally ; the neck bent upwards, very much shorter than the body of the
sheath, everted at its margin, frequently with a lateral lunate excision,
containing interiorly several angular valve-like appendages which close
the aperture when the animalcule is contracted ; body of animalcule trans-
parent or pale sea-green, lobes of the peristome of equal size, ovate, about

GENUS FOLLICULINA. 599

twice as long as broad, their extremities broadly rounded ; endoplast
spheroidal, subcentral. Length of entire lorica 1-192" to 1-120".
HAB. — Salt water.

The favourite haunt of this species is, according to Stein, among the angles
formed by the finer divisions of the fronds of Ceramium, Polysiphonia, and other
filamentous seaweeds. It frequently happens, as shown at PI. XXIX. Fig. 35, that
the attached basal portion of the lorica is supplemented anteriorly by a small keel-
like lamina of similar consistence, and presenting in profile the aspect of a
triangular, wedge-shaped fulcrum, while in the rear the lorica is made fast to the
object of support by a backward directed lamina of similar shape and character.
The examples of this species, as met with by Stein, and Claparede and Lachmann,
by the former in the Baltic, and by the latter authorities in the North Sea, present
some slight differences in both the character of the lorica and contained animalcule.
In the original form of Freia (Folliculina} elegans, as described by the Swiss autho-
rities, a conspicuous lunate excision was always observed on the left-hand side of
the aperture of the lorica, two or more triangular valve-like laminae projected
forwards from within the interior of the short tubular neck, while the contractile
vesicle was simply spherical and situated on the median line a little behind the
endoplast. In the examples referred to this type by Stein, on the other hand,
the oral aperture of the lorica is even and entire, a single sickle-shaped valvular
lamina projects backwards from the upper wall of the interior of the neck,
while the contractile vesicle is stationed on the ventral side of, and slightly
in advance of, the central endoplast, and, in place of being simply spheroidal,
exhibits at diastole supplementary lateral extensions. If not entitled to the rank
of an independent species, Stein's type would appear to represent at the least a
well-marked local variety.

Folliculina producta, Str. Wright sp. PL. XXIX. FIGS. 29-32.

Lorica pale yellow-brown, inflated at its base, produced anteriorly into
a neck-like extension, often equal to five or six times the length of this
body portion ; the neck regularly and transversely annulate throughout its
extent ; animalcule deep blackish-green, exceedingly attenuate, projecting
to a considerable distance beyond the aperture of the lorica ; peristomal
lobes much prolonged, of equal size, ligulate or ribbon-like, curved at
their extremities. Length of fully developed lorica i-ioo".

HAB. — Salt water : Queensferry, Ireland (Strethill Wright).

While the transversely annulate neck-like prolongation of the lorica of this
species approximates it somewhat to one variety of Folliculina ampulla, it may be
readily distinguished from that type by the extraordinary development of this
region, which often contains as many as twenty-seven transverse annulations. The
lobes of the peristome are also, in comparison with that form, much more
lengthened and attenuate. Several phases of the free-swimming larval condition of
Folliculina producta have been observed and figured by its discoverer, Dr. Strethill
Wright, and will be found reproduced at PI. XXIX. Figs. 30-32. At these early
periods of its existence there was no trace of a sheath or of the ear-like peristomal
lobes; the animalcule being either ovate or of cylindrical form, pointed at the
posterior extremity, and abruptly truncate at the anterior one, which bore rather
larger cilia than those of the general surface of the body. One of these larvae was
observed to attach itself and complete the construction of its lorica, including the
prolonged annulated neck, within the course of a single night. Whether the free-
swimming peristomeless larvae are produced by fission or through internal gemmation
from the parent form remains to be discovered.

600 ORDER HETEROTRICHA.

Folliculina stylifer, Str. Wright sp. PL. XXIX. FIGS. 19 AND 20.

Lobes of the peristome even, spatulate, about three times as long as
broad, the left-hand lobe bearing at its apical extremity a single, straight,
rigid, rod-like style, which equals in length the lobe to which it is attached,
and projects beyond and guards the aperture of the lorica when the
animalcule is contracted ; body of lorica usually concealed from view, the
exposed anterior portion straight, cylindrical, its margin even, not expanded.

HAB. — Salt water.

The anterior region of the lorica, with the projecting peristome, as here re-
produced, is alone depicted in Dr. Strethill Wright's delineation of this species.
The stylate appendage projecting from the left-hand peristome lobe, which acts as
efficiently as the valvular apparatus of Folliculavia elegans in protecting the retracted
animalcule from intrusion from without, serves, notwithstanding our imperfect
knowledge of the remaining characteristics, to distinguish this type from all other
known representatives of the genus.

Folliculina hinmdo, S. K. PL. XXIX. FIG. 39.

Lorica flask-shaped, pale sea-green when young, dark bottle-green
when old ; attached posteriorly ; constricted centrally and again dilated
before narrowing off to form the short, circular, and slightly everted distal
aperture. Animalcule bottle-green ; peristomal lobes very long and narrow,
uniform in size, eight or ten times as long as broad, or equal in length when
extended to that of the entire body ; endoplast ovate, subcentral ; contractile
vesicle posteriorly located. Length of lorica 1-200".

HAB. — Salt water : Channel Islands.

This species was obtained by the author, at Guernsey, in the autumn of the year
1870 and on subsequent occasions, attached in some abundance to various marine
Polyzoa and seaweeds, the swallowtail-like aspect presented by the peristomal
lobes when seen from the dorsal or ventral aspect in their fully extended state,
suggesting the title conferred upon it. The alternately constricted and inflated
anterior portion of the lorica of this species, in addition to the slender and attenuate
contour of the peristomal lobes, distinguishes it readily from the forms previously
described. The basis of attachment of the lorica in Folliculina hirundo occupies a
very small area of the surface, being limited entirely to the posterior region.

Folliculina Boltoni, S. K. PL. XXIX. FIG. 36.

Lorica flask-shaped, attached laterally, transparent when young, chest-
nut-brown when old; neck bent upwards, very short, its margin even,
circular, not everted. Animalcule transparent ; peristomal lobes rounded,
of unequal size, one of these, usually the left, attaining twice the dimen-
sions of the other. Length of lorica, 1-200".

HAB. — Fresh water, on Anacharis and other aquatic plants.

This species is named after its first discoverer, Mr. Thomas Bolton, to whom the
author is indebted for the opportunity of examining examples of this and many other
interesting infusorial forms described in this volume. So far it would appear to be
the only representative of the genus Folliculina yet obtained in fresh water, and may
be otherwise distinguished from its several marine congeners by the unequal size of its

GENUS CH&TOSPIRA. 6oi

peristomal lobes ; the lorica most nearly resembles that of F. elegans, but the margin
is even and not everted, and there are no internal valves. The colour and con-
sistence of this structure apparently agree with those of various species of the genera
Cothurnia and Vaginicola, and in the absence of the animalcule might be mistaken
for the lorica of Vaginicola (Platycpla} longicillis. The species oiLagotia (Folliculina)
referred to though not described by Mr. Barrett* as occurring in company with
Stentor Baretti, in the river Thames, near Moulsford, is probably identical with the
present type.

GENUS III. CH^ETOSPIRA, Lachmann.

Animalcules highly elastic and contractile, inhabiting an attached
mucilaginous or horny sheath or lorica, to the inner wall of which they are
not, however, organically united ; peristome represented by a slender, ligulate
extension of the anterior region, which, when the animalcule is expanded,
projects beyond the aperture of the lorica and is twisted into a more or less
extensive Igeotropous or left- ascending spire ; a hyaline membraniform
expansion extending laterally along the broad portion of the ligulate
peristome and forming with it a gutter-like channel, which conducts to the
oral aperture ; this adoral groove continued backwards into the sub-
stance of the parenchyma as a narrow tubular pharynx ; a row of large,
prominent, cirrate adoral cilia bordering the entire length of one side of
the ligulate peristome, commencing at the apical extremity and terminating
in the vicinity of the mouth ; cilia of the general cuticular surface fine,
distributed in even longitudinal rows ; supplementary, delicate, hair-like
setae sometimes projecting in an irregular manner from the surface of the
integument. Inhabiting fresh and salt water.

Lachmann, when instituting the generic title of Chcztospira,^ hazarded the
opinion that the animalcule to which he gave that name might possibly be identical
with the, at that time, very imperfectly described Stichotricha secunda of Perty.
Stein, who has since met with this last-named type, and figured and described
it in his monograph of the Hypotricha, adopts this view, and has no hesitation in
pronouncing the two to be the same. The present author is inclined, however, to
dissent from this decision, having observed an animalcule which, while corresponding
in all important points with Lachmann's species, is altogether distinct from the one
figured by Stein, and referred correctly, so far as it is possible to decide, to Party's
Siichotricha. This latter form, as made known by the more recent investigations of
Stein, and described further on in this volume is, as first premised by Perty, an
unmistakable representative of the Hypotrichous family of the OxytrichiJa, sharing
with the more ordinary members of that group the characteristic ciliation, which is
restricted to the ventral surface of the body, and there limited, in addition to the
adoral fringe, to a few widely separated rows of short, non-vibratile, ventral and
marginal, setose cilia. In Chcetospira, on the other hand, the character and distri-
bution of the cuticular cilia is entirely diverse, taking the form of fine vibratile cilia,
which are distributed in close parallel rows throughout the surface of the integument
as in an ordinary Holotrichous animalcule, the anterior fringe of powerful adoral
cirri necessitating, however, its reference to the higher order of the Heterotricha.
Among these it is evident that its correct position is not very remote from the
genus Folliculina, and with certain representatives of which, such as F. producta or
F. hirundo — premising one of the ligulate peristome-lobes to be suppressed and
the remaining one to be twisted in a spiral manner — it might be appropriately

'Monthly Microscopical Journal,' April 1870. f Muller's 'Archives,' p. 362, 1856.

602 ORDER HETEROTRICHA.

compared. Although thus demonstrating the essential distinctness of the two
genera Chcetospira and Stichotricha, and the necessity of referring them to even
diverse orders of the Ciliata, the likeness between the two in both habits and in
certain important structural characteristics cannot be overlooked. This is most
prominently manifested in the peculiar form and deportment of the peristome and
in the custom of each to build and inhabit a mucilaginous or horny sheath.
These two generic types would appear to afford indeed but one among the many
instances that occur in demonstration of the close approximation to one another of
two seemingly widely diverse groups, as circumscribed by the necessarily artificial
boundaries of zoological taxonomy.

Chsetospira Muelleri, Lachmann. PL. XXIX. FIGS. 37 AND 38.

Sheath or lorica flask-shaped, transparent, of horny consistence, the
enclosed animalcule adapting the contour of its body to the shape of the
lorica ; the spire formed by the flexure of the ligulate peristome describing
more than a single turn ; cilia of adoral fringe longest centrally, diminishing
gradually in length towards the apical and basal extremities; fine, and
apparently retractile, setose cilia sometimes forming a conspicuous series
down the border of the peristome, opposite to that fringed by the adoral
cilia; endoplast spherical, subcentral ; contractile vesicle anteriorly situated.
Length of extended body 1-160". HAB. — Fresh and salt water.

This species, while originally characterized as a fresh-water inhabitant occurring
only in the open cells of decaying leaves of Lemna tristilca, has been met with by
the author under numerous varying conditions, not unfrequently with its transparent,
flask-shaped lorica independently attached to growing leaves of Myriofhyllum and
other water plants, while on more than one occasion examples were encountered
that had built their habitations within the vacated egg-capsules of various species of
Rotiferae. Although Claparede and' Lachmann have mentioned that it is only in
relationship with the following type that supplementary fine setae have been
detected upon the general surface of the body, these structures, as figured in the
accompanying illustration, have been frequently observed by the author in the present
variety. It seems highly probable that these supplementary setae, as in the case
of certain Stentors, are not of constant recurrence, but are extruded and retracted
at the will of their possessor. The contractile vesicle in the examples personally
examined occupied a much more anterior position than is given by Lachmann,
being indeed considerably in advance of the oral aperture and, as shown in the
accompanying illustration, in close vicinity to the distal termination of the lateral
membranous expansion, and to the first abrupt flexure of the peristome ; the systole
of this organ was found to recur with unvarying regularity every fifteen seconds.
The anal aperture is reported by Lachmann as occupying a position closely adjacent
to that of the contractile vesicle as here given.

A species superficially so closely resembling C. Muetteri has been obtained by
the author from salt water that it is not thought desirable at present to introduce
it under a new title, this marine form being probably also identical with the
animalcule briefly described some years since by Dr. Strethill Wright under the
name of Chcetospira marina*

Chsetospira mucicola, Lachmann.

Sheath or lorica entirely mucilaginous, transparent ; the anteriorly pro-
duced ligulate peristome forming, in the expanded state, less than a complete
spiral turn, the long adoral cilia that fringe its border being longest at the
* 'Quarterly Journal of Microscopy,' vol. ii. 1862.

GENUS TINTINNUS. 603

anterior extremity, the foremost one in particular being twice as long and
thick as any of the succeeding ones ; supplementary fine setae developed
throughout the general surface of the body. Dimensions unrecorded.
HAB. — Fresh water, among confervoid algae.

Supplementary Species.

In the 'Monthly Microscopical Journal' for October 1875, an animalcule is
figured and described by Dr. C. T. Hudson under the title of Archimedea (Chceto-
spira) remex. As seen only with the twisted anterior extremity protruded from the
opaque attenuate lorica, it would seem to possess a strong claim for admission to
the present genus ; Dr. Hudson's representation, however, of the animalcule in its
free-swimming state, demonstrates it to be a Hypotrichous form referable to Perty's
genus Stichotricha, under which heading it receives fuller attention later on. This
same species has been met with by Mr. Thomas Bolton, and has been referred
to by him in the 'Midland Naturalist' for 1875 under the name of Chcetospira
cylindrica, a title provisionally conferred upon it by the present author when familiar
only with Mr. Bolton's delineations of the animalcule as seen in its sedentary semi-
extended condition.

Fam. IV. TINTINNODJE, C. & L.

Animalcules free-swimming or sedentary, mostly inhabiting an indurated
sheath or lorica, to the bottom or side of which the ovate or pyriform body
is usually attached by a retractile pedicle or thread-like prolongation of the
posterior extremity. Oral aperture eccentric, terminal or subterminal, peri-
stome subcircular, bordered by a single or complex, evenly circular or spiral
fringe of large cirrate cilia; the general cuticular surface more or less
completely clothed with fine vibratile cilia.

By Stein the representatives of Tinfinnus, the type genus of the family, are
included among the Peritricha, he having failed to detect in the few examples he
examined the presence of the fine cuticular cilia so amply demonstrated to be present
in a number of species through the more extensive researches prosecuted by Messrs.
Claparede and Lachmann with reference to this especial group.

GENUS I. TINTINNUS, Schrank.

Animalcules ovate or pyriform, attached posteriorly by a slender
retractile pedicle within a more or less indurated sheath or lorica; the
lorica floating freely in the water, not attached to foreign organisms;
peristome-field occupying the entire anterior border, circumscribed by a
more or less complex spiral wreath of long, powerful, cirrose cilia, the left
limb or extremity of which is spirally involute and forms the entrance to the
oral fossa ; this fossa continued into the substance of the parenchyma as
a short, tubular pharynx ; anal aperture posteriorly situated, subterminal ;
cuticular cilia very fine, distributed evenly throughout, clothing both the
body and the retractile pedicle.

The genus Tintinnus was instituted by Schrank * for the reception of the Trichoda
inqitilinus of Miiller and two other doubtful loricate forms whose specific identity

* ' Fauna Boica,' 1803.

Lj LIBRARY so

604 ORDER HETEROTRICHA.

cannot at present be determined. The generic group, even as more explicitly cir-
cumscribed by Ehrenberg and later authorities is, however, by no means so
clearly defined as might be wished. Under this title are indifferently included
animalcules that live, as indicated in the foregoing- diagnosis, an entirely free-swim-
ming or pelagic life, and others whose loricae, like those of Vaginicola or Folli-
culina, are permanently attached to water-plants or other submerged objects ; the genus
indeed, as defined by Eichwald, is erroneously represented as composed entirely of
such sedentary forms. In recognition of the essential difference that subsists between
these respective pelagic and sedentary types, it has been considered desirable to
separate from Tintinnus all those animalcules that belong to the last-named
category and to confer upon them the new generic title of Tintinnidium. The
genus Tintinnus, as limited only to the free-swimming or pelagic forms, still presents
structural characteristics upon which modern investigators have as yet arrived at a
by no means harmonious interpretation. Although Claparede and Lachmann have
succeeded in demonstrating that the entire cuticular surface in the majority of the
species examined by them, inclusive of the type form T. inquilinus, is clad with fine
vibratile cilia, as in Stentor, Follicularia, and other Heterotricha, no such finer sup-
plementary cilia were observed by the founder of the genus or other more recent
authorities. Even Stein, whose personal acquaintance, however, is apparently
limited only to the two species Tintinnus inquilinus and Tintinnus (Tintinnidium}
fluviatilis, failed to detect the presence of these cilia, and has in consequence referred
the genus, together with Tintinnopsis, to the order of the Peritricha. The positive
evidence afforded by Claparede and Lachmann's investigations nevertheless out-
weighing that of a negative nature only as produced by Stein in connection with
this structural characteristic, the author has felt constrained to support the views of
the first-named authorities, and to concede to the genus a corresponding position
among the Heterotrichous order. It is at the same time by no means improbable
that many Tintinnoid forms exist which differ from the typical members of the
genus through the absence of a cuticular ciliary clothing, for which it will be requisite
to institute a new generic title, allocating them to the order of the Peritricha. The
Tintinnus subulatus of Ehrenberg is not improbably of this number.

All the known representatives of the genus Tintinnus, as here defined, inhabit
salt water, and are notable for the extraordinary rapidity of their movements.
Placed under the microscope they dart to and fro across the optic field with the
swiftness of an arrow, a considerable amount of difficulty being necessarily involved
in the apprehension of their more minute structural characters, and it is only
indeed in examples that have become entangled among other objects present, or
are held tight by compression between the slide and covering-glass, that these
details can be sufficiently investigated. Through the researches of Claparede
and Lachmann a very considerable addition has been made to the number of
species included in the genus Tintinnus by Ehrenberg. It is necessary, however,
to remark that in a large number of them the empty sheaths or loricae alone
have been observed, and it is therefore quite possible that certain of these struc-
tures may hereafter be found to belong to such other pelagic loricate types as
Codondla, Tintinnopsis and Dictyocysta. In their adoral ciliary system and general
contour the animalcules of Tintinnus correspond to some extent with those of the free-
swimming illoricate Peritrichous genus Strombidium, with which again they are still
more intimately united through the newly introduced and essentially Heterotrichous
type Strombidinopsis.

Tintinnus inquilinus, Mull. sp. PL. XXXI. FIG. 15.

Lorica subcylindrical, diaphanous, four or five times as long as broad,
slightly attenuate posteriorly, the extreme ends abruptly truncate, anterior
margin smooth, not everted; body of animalcule often fixed to one side
instead of to the bottom of the lorica, elongate-conical, pedicle not quite

GENUS TINTINNUS. 605

as long as the body ; peristome-field circular, excavate, its inner margin
bordered by several cycles of long, powerful adoral cilia ; contractile vesicle
anteriorly situated. Length of lorica 1-200" to 1-130".
HAB. — Salt water : Norwegian coast.

Transverse fission has frequently been observed by Stein in association with this
species, this phenomenon being heralded by the development around the centre
of the elongated body of the animalcule of a second girdle of powerful cirrose
cilia. The Tintinnus inquilinus of Ehrenberg represents two essentially distinct
animalcules ; the free-swimming type, obtained by him from the harbour of Copen-
hagen, only being identical with the present species. The second form, encountered
at Kiel, inhabiting a lorica which is permanently attached posteriorly to algae and
other objects, and which is alone represented in his illustrations of T. inquilinus* is
not a true Tintinnus and will be found described further on in connection with the
name of Tintinnidium marinum. The fine cuticular cilia of the present species,
clearly indicated in Claparede and Lachmann's drawing, have been accidentally
omitted by the artist in the accompanying reproduction of their figure.

Tintinnus subulatus, Ehr. PL XXXI. FIG. 5.

Lorica elongate-cylindrical, diaphanous, from twelve to fifteen times as
long as broad, terminating posteriorly in a long, sharp, and sometimes
slightly curved spine-like point, the anterior region ornamented with several
parallel transverse annulations, the front margin not everted ; animalcule
elongate, subcylindrical, having a very long, slender, retractile pedicle,
entirely enclosed within its protective sheath. Length of lorica 1-120".

HAB. — Salt water : abundant in the North Sea.

It is possible, as already intimated by Ehrenberg, that the Vorticella vaginata of
O. F. Miillert is identical with this species, though at the same time the body of the
animalcule in the last-named type presents a more globose outline, and there is a
faint indication in Miiller's figures, though not referred to in the text, of the lorica
being attached posteriorly as in Tintinnidium, or an ordinary Vaginicola. To some
extent, again, the figures referred to recall the initial condition of Zoothamnium
arbuscula or Z alternans (PL XXXVII. Figs. 6 and 7), in which a single large
subglobose zooid surmounts the relatively thick transparent pedicle, the distal
extremity of which alone encloses the retractile filament, and bears consequently
no inconsiderable resemblance to a hyaline lorica.

Tintinnus mucicola, C. & L. sp. PL. XXXI. FIG. 16.

Lorica subcylindrical, mucilaginous, transparent, its surface somewhat
uneven, little over twice as long as broad ; body of animalcule ovate or
pyriform, occupying about one-third of the cavity of the lorica, retractile
pedicle very long, fixed to the bottom of the sheath and permitting the
animalcule to protrude considerably beyond its anterior margin. Length
of lorica 1-150". HAB. — Salt water: Norwegian coast (C. & L.).

It is rather doubtful whether this species is not rightly referable to the closely
allied sedentary genus Tintinnidium, and in that case would scarcely be distinguished
from Tintinnidium marinum. Claparede and Lachmann testify to its close resem-

* ' Infusionsthierchen,' pi. xxx. fig. 2.

t ' Animalcula Infusoria,' pi. xliv. figs. 12 and 13, 1786.

6o6 ORDER HETEROTRICHA.

blance to, and possible specific identity with, the fresh water Tint'mnus (Tintin-
nidium) fluviatihs of Stein, but are at the same time altogether silent upon the
subject of its either attached or pelagic habits.

Tintinnus obliquus, C. & L. PL. XXXI. FIG. 26.

Lorica elongate, subcylindrical, transparent, homogeneous, seven or
eight times as long as broad, narrower and conical posteriorly, the anterior
margin even, straight ; animalcule conical, its anterior margin very obliquely
truncate, projecting, when extended, to nearly its entire length beyond the
anterior margin of its lorica. Length of lorica 1-150".

HAB. — Salt water : coast of Norway (C. & L.).

This species differs from T. inquilinus in the oblique contour of the peristomal
margin of the animalcule only, and in the regular conical shape of the posterior
extremity of the lorica; this structure is likewise proportionally much more elongate.
In common with the last-named type the animalcule is often found with the pedicle
attached high up on one side of the lorica ; Lachmann's sketch represents an
example so fixed to the centre of the interior of its sheath, and with the body almost
entirely extruded from the aperture.

Tintinnus amphora, C. & L. PL. XXXI. FIG. 12.

Lorica transparent, homogeneous, elongate vase-shaped, about three and
a half times as long as broad, inflated most a little below the centre, the
anterior margin even, circular, slightly everted, followed by a narrower
neck-like portion. Animalcule undescribed. Length of lorica 1-125" to
1-80". HAB. — Salt water : Sartoro, Norway (C. & L.).

No description of the living animalcule of this species has been recorded, but a
motionless stalked cyst was on several occasions observed within the lorica. Some-
times this cyst contained a single granular body, while at other times it was broken
up into numerous smaller granular spherules, each of which contained a colourless
vesicle. Claparede and Lachmann were undecided whether or not to regard these
cysts as intruding organisms or as encysted conditions of the original inhabitants.
The latter interpretation may, however, probably be accepted, taking into consider-
ation their stalked condition and the almost universal occurrence of an encysted
stage throughout the whole class of infusorial animalcules. Similar encysted bodies
were observed by these authorities in connection with various other members of the
genus Tintinnus.

Tintinnus acuminatus, C. & L. PL. XXXI. FIG. 14.

Lorica diaphanous, homogeneous, elongate-cylindrical, ten or twelve
times as long as broad, the posterior extremity acuminately pointed, the
anterior margin even, everted. Animalcule not observed. Length of lorica
i -80''. HAB. — Salt water : Norwegian coast (C. & L.).

No account of this animalcule has been recorded ; the lorica, while most nearly
resembling that of T. subulatus, differs from that species in its everted and non-
annulate anterior margin and in its acuminate posterior termination, which is
described as being facetted in an elongate-pyramidal manner.

Tintinnus Steenstrupii, C. & L. PL. XXXI. FIG. 20.

Lorica diaphanous, homogeneous, subcylindrical, elongate vase-shaped,
seven or eight times as long as broad ; the posterior extremity slightly

GENUS TINTINNUS. 607

inflated and ornamented with four longitudinal grooves or sulci, the anterior
margin widely everted. Animalcule elongate-ovate, occupying, when
retracted, the entire posterior half of the lorica. Length of lorica 1-125".
HAB. — Salt water : Nonvegian coast (C. & L.).

Tintinnus quadrilineatus, C. & L. PL. XXXI. FIG. 13.

Lorica transparent, homogeneous, shortly vase-shaped, about three times
as long as broad ; anterior margin widest and largely everted, gradually
tapering towards the posterior extremity where it terminates in an obtuse
point ; four deep grooves extending from the posterior extremity nearly as
far as the anterior margin. Animalcule undescribed. Length of lorica
1-150". HAB. — Norwegian coast (C. & L.).

Tintinnus denticulatus, Ehr. PL. XXXI. FIGS. 18 AND 19.

Lorica diaphanous, cylindrical, two or three times as long as broad,
terminating posteriorly in a long acute point, surface regularly shagreened
with minute hexagonal facets ; the anterior margin finely denticulate, not
everted. Animalcule unobserved. Length of lorica 1-175".

HAB. — Salt water : Baltic Sea and Norwegian coast.

Claparede and Lachmann, who met with this species abundantly on the coast of
Norway, remark that the lorica is of very variable form, the width being sometimes
equal to the length, while occasionally the posterior portion, before narrowing off to
the terminal subulate point, is considerably inflated. The very beautiful hexagonal
facetted structure of the test, as reproduced at PI. XXXI. Fig. 1 9, is only exhibited
under a high magnification, the facets under a moderate magnifying power present-
ing the appearance of minute circular areas. Unfortunately no account of the
animalcule inhabiting this elegant lorica has been placed on record by Ehrenberg,
or Claparede and Lachmann, which thus leaves it doubtful whether we have here
the protective sheath of a true Tintinnus, or the facetted test of a Dictyocysta or
Codonella. Tintinnus denticulatus, while described by Ehrenberg in the year 1840,*
was first met with abundantly by Professor C. Boeck, in the vicinity of Spitsbergen,
in the year 1839, and subsequently by the same investigator in the Fjord of Christi-
ania. Its distribution would appear to be general and abundant throughout the seas
of Northern Europe.

Tintinnus Ehrenbergii, C. & L. PL. XXXI. FIGS, i AND 2.

Lorica colourless, evenly cylindrical, very thick, finely granulate, about
three times as long as broad ; posterior extremity rounded, and then pro-
duced into a short, obtuse and usually curved, spur-like point ; anterior
margin even, not everted. Animalcule pyriform, attached posteriorly by
a pedicle which equals its body in length, occupying, when retracted, about
one-third of the interior of the lorica ; contractile vesicles two in number,
posteriorly located. Length of lorica 1-120".

HAB. — Salt water : Norwegian coast (C. & L.).

Claparede and Lachmann describe this form as exceeding, in both the dimensions
of the animalcule and in the size and thickness of the lorica, any other species met

* 'Monats. Berl. Akad.,' p. 201, 1840.

608 ORDER HETEROTRICHA.

with by them. The surface of the exceedingly thick and massive lorica, while
seeming to be simply granulate under a magnifying power of 300 diameters, is
shown, when still further enlarged, to be ornamented with hexagonal facets in a
manner corresponding with that of T. denticulatus, though on a much finer scale.

Tintinnus lagenula, C. & L. PL. XXXI. FIGS. 21 AND 22.

Lorica broadly flask- or helmet-shaped, nearly as wide as long, with a
very short and slightly narrower everted neck, and inflated body-portion ;
posterior region verrucose and opaque, divided into somewhat coarse poly-
gonal areas or facets, the anterior end smooth and diaphanous ; extended
animalcule nearly equal in length to the lorica, two zooids sometimes
inhabiting the same domicile. Length of lorica 1-80".

HAB. — Salt water : Norwegian coast (C. & L.).

The contour of the lorica of this species, combined with the verrucose and
facetted aspect of its posterior region, coincides remarkably with that of Codonella
galea, Hkl., described later on. As seen with a magnification of 700 diameters,
each of these polygonal facets exhibits a central spot which Claparede and Lach-
mann are disposed to regard as a perforation. A similar formation, as represented
in the lorica of Codonella galea, is interpreted by Haeckel as due to the enclosure
within each facet of a minute siliceous corpuscle.

Tintinnus cinctus, C. & L. PL. XXXI. FIG. 10.

Lorica cylindrical, slightly opaque, everted at its anterior margin, about
three times as long as broad, terminating posteriorly in an elongate, often
recurved point ; the whole surface ornamented with widely separated trans-
verse annulations. Animalcule unobserved. Length of lorica 1-200".

HAB. — Salt water : coast of Norway.

The possible identity of this type with the Codonella orthoceras of Professor
Haeckel receives attention in the description given of that species.

Tintinnus cothurnia, Ehr.

Lorica cylindrical, diaphanous, attenuate and truncate posteriorly ;
transversely but indistinctly annulate throughout. Length of lorica 1-440".
HAB. — Fresh water : Baltic Sea.

This species is described by Ehrenberg in company with T. denticulatus in the
' Monatsbericht d. Berliner Akademie,' p. 201, 1840. Its nearest ally would appear
to be the Tintinnus cinctus of Claparede and Lachmann.

Tintinnus helix, C. & L. PL. XXXI. FIG. 24.

Lorica cylindrical, four times as long as broad, slightly opaque from the
incorporation of minute granular particles ; grooved or sulcate posteriorly
in a spiral or helicoidal manner, the anterior extremity transversely
annulate ; the distal margin even, not everted, the opposite or posterior
end terminating in a short and often slightly recurved point. Animalcule
unobserved. Length of lorica 1-165".

HAB.— Salt water : Norwegian coast (C. & L.).

GENUS TINTINNUS. 609

Tintinnus annulatus, C. & L. PL. XXXI. FIG. 25.

Lorica subcylindrical, irregularly inflated posteriorly, terminating in a
short acuminate point, the anterior margin not everted ; consistence opaque
and coarsely granular through the incorporation of foreign particles; the
posterior body-portion exhibiting several annular constrictions. Animalcule
not observed. Length 1-120".

HAB. — Salt water : Norwegian coast.

Tintinnus campanula, Ehr. PL. XXXI. FIG. n.

Lorica campanulate, widely dilated anteriorly, tapering posteriorly,
terminating in an attenuate point ; substance coarsely granulate through
the incorporation of foreign particles. Body of animalcule occupying when
retracted about one-half of the cavity of the lorica. Length of lorica
1-166" to 1-125". HAB. — Salt water: Norwegian coast (C. & L.).

Claparede and Lachmann propose to identify the form, as here figured, with the
species first introduced under the same title by Ehrenberg, but with no illustration,
in the ' Monatsb. der Berlin. Akad.,' p. 201, 1840. While, however, Ehrenberg's
brief diagnosis of his Tintinnus campanula appears to accord with the present type,
the dimensions of the lorica, as given by him, are much more minute, not exceeding
1-288".

Tintinnus ventricosus, C. & L. PL. XXXI. FIG. 31.

Lorica coarsely granulate, ventricose or bottle-shaped, nearly as broad
as long ; the wider anterior portion surmounted by a short, narrow, slightly
everted neck, terminating posteriorly in an obtuse point. Animalcule
unobserved. Length of lorica 1-250".

HAB. — Salt water : Norwegian coast.

Tintinnus urnula, C. & L. PL. XXXI. FIG. 3.

Lorica cylindrical, transparent and homogeneous, of a slightly smoky
hue, little over twice as long as broad, terminating posteriorly in a
sharp subulate point; the anterior region not everted, ornamented at a
little distance from its terminal margin with a raised border or annulation.
Length of lorica 1-175". HAB. — Salt water : Norwegian coast (C. & L.).

Claparede and Lachmann merely remark of this animalcule that it possesses a
single contractile vesicle. In their drawing of the species, here reproduced, they
represent an example that is apparently preparing to increase by fission. In this
instance a second fascicle of cirri is in course of development at the posterior
extremity, its position corresponding closely with that assumed by the posteriorly
affixed zooid of a Vorticella during the act of conjugation. It is just possible that a
similar interpretation might be applied in the present case.

Tintinuus Ussowi, Mereschk. PL. XXXI. FIG. 4.

Lorica transparent, attenuate, straight, subcylindrical, ten or twelve
times as long as broad, slightly widest anteriorly, tapering gradually back-
wards, and terminating posteriorly in a sharply acuminate or subulate pro-
longation ; the anterior third ornamented with from twelve to fifteen finely

VOL. II. L

6 10 ORDER HETEROTRICHA.

denticulate transverse annulations, the remainder of its surface perfectly
smooth ; enclosed animalcule as in Tintinnus inquilinus. Length of
lorica 1-192". HAB. — Salt water : White Sea (Mereschkowsky).

Excepting for the presence of the denticulate annuli at the anterior extremity,
the lorica of this species is indistinguishable from that of T. subulatus.

Tintinnus mediterraneus, Meresch.

Lorica transparent and homogeneous, urceolate, scarcely longer than
broad, abruptly narrowed in a neck-like manner anteriorly, not everted, the
posterior extremity obtusely rounded or terminating in an acute point ;
four or five closely approximated parallel linear annulations ornamenting
the neck-like portion. Animalcule not observed. Length of lorica 1-160".

HAB. — Salt water : Black Sea and Bay of Naples (Mereschkowsky)

This species is figured and described by Mereschkowsky in company with
several other interesting marine types in the 'Annals and Magazine of Natural
History' for April 1881. The two forms of this species, distinguished respectively
by the rounded or acuminate termination of the posterior extremity of their loricas,
were obtained respectively from the Black Sea and Bay of Naples, and receive from
their discoverer the separate designations of Tintinnus mediterraneus var. pontica and
T. med. var. neapolitana.

Supplementary Species.

Quite recently, Professor H. Fol has contributed to the ' Archives des Sciences
Physiques et Naturelles,' torn, v., January 1881,* a memoir on the organography of
the genus Tintinnus. Among other important points, he therein maintains that the
oral ciliary system exhibits a far more complex structural plan than that of either
one or morp concentric circles or spiral revolutions, as represented by previous
authorities. In place of this he reports of two new Mediterranean species, Tintinnus
ampulla and T, spivalis, as examined by himself, that the cilia of the peristome are
all arranged in accordance with about twenty curved lines, which, starting from
the interior of the disc, become tangential to its margin, the longest and strongest
cilia being developed at the periphery. Presuming that such a structural plan of
the ciliary system as is described and delineated by Professor Fol of these two types
actually exists, the author is unable to regard them as eligible for admission into
the genus Tintinnus., the broad petaloid modification of the peripheral border, with
its associated cilia, being altogether distinct from what obtains in the typical
members of that genus as verified in so large a number of species by Claparede and
Lachmann and other recent observers, and as also certified by the author in the case
of Tintinnus subulatus. These two forms are hence provisionally referred to the
Peritrichous order in connection with the new generic title of Petalotricha.

Professor Fol has further proposed to subdivide Tintinnus, as here defined, into
two subordinate generic groups with reference to the consistence of their pro-
tective loricae or tests. Following out this plan, he suggests the title of Tintinnus
for those forms only in which the test is entirely smooth and plane, and that of
Coniocydis for those species in which the test is more or less marked with trans-
verse striae and impregnated, especially in parts, with foreign mineral particles.
This suggested innovation is not, however, advocated in this treatise, the composi-
tion of the test being regarded by the author as a character entirely subordinate to
the structure of the animalcules by which they are fabricated. If, indeed, such a
distinction must be recognized, it would be also desirable to establish a third genus
for such forms as Tintinnus subulatus and T. Ussowi, in which the test or lorica,

* This paper is translated by Mr. W. S. Dallas in the ' Annals and Magazine of Natural
History' for April 1881.

GENUS TINTINNIDIUM. 6ll

while homogeneous, is transversely annulate ; and a fourth for such as 71 ventricosus,
in which the test is coarsely granular but not annulate. So far, indeed, as the granular
consistence of this excreted element is concerned, it is without doubt dependent
to no small extent upon surrounding conditions, such as the clearness or turbidity
of the waters which the animalcules inhabit.

GENUS II. TINTINNIDIUM, S. K.
(Tintinnus ; oidos, form.)

Animalcules ovate or pyriform, resembling those of the genus Tintinnus,
but excreting a sheath or lorica, usually of a mucilaginous consistence,
which is permanently affixed to foreign objects. Inhabiting salt and fresh
water.

This new genus is here instituted for the reception of the Tintinnus inquilinus,
in part, of Ehrenberg, and the Tintinnus fluviatilis of Stein — two forms closely
allied to one another, and which differ from the typical representatives of the last-
named genus in their essentially sedentary habits.

Tintinnidium marinum, Ehr. sp. PL. XXXI. FIG. 9.

Lorica transparent, subcylindrical, two and a half to three times as long
as broad ; animalcule when retracted filling two-thirds of the cavity of the
lorica, projecting beyond its orifice, when extended, to a distance of one-
half of its total height ; retractile pedicle in full extension equal in length
to the body, sometimes attached to the bottom and sometimes to one side
of the inner surface of the lorica. Length of lorica 1-240".

HAB. — Salt water, attached to various marine algae.

The above specific title is here associated with that variety of the so-called Tintin-
nus inquilinus met with by Ehrenberg attached to algae at Kiel, and as figured by
him at pi. xxx. fig. ii. i and 2, of his ' Infusionsthierchen.' This animalcule is
altogether distinct from the typical free-swimming representatives of the species first
described by Schrank, and as also encountered by Ehrenberg in the harbour of
Copenhagen. Its possible identity with the Tintinnus mucicola of Claparede and
Lachmann, delineated at fig. 16 of the same plate, is adverted to in the description
given of that species.

Tintinnidium fluviatilis, Stein sp. PL. XXXI. FIG. 8.

Lorica cylindrical, transparent, mucilaginous, surface uneven, frequently
with incorporated foreign particles ; body of animalcule conical or campanu-
late, occupying about one-half of the cavity of the lorica, projecting when
extended to nearly one-half its length beyond its aperture ; retractile
pedicle attached to either the side or the bottom of the cavity of the lorica ;
contractile vesicle spherical, subcentral ; endoplast elongate-ovate, laterally
located, having attached to it a minute, round endoplastule. Length of
lorica 1-200". HAB. — Fresh water, on aquatic plants.

With the exception of its fresh-water habitat, this species seems to differ very
little from the form previously described. In addition to its observation by both
Stein and Claparede and Lachmann, the present author has received drawings of
an apparently identical form through Mr. Thomas Bolton, the originals of which

L 2

6l2 ORDER HETEROTRICHA.

were obtained by him from the neighbourhood of Stourbridge, Worcestershire,
attached to the leaves and stems of Anacharis alsinastrum. In one of the sketches
forwarded two examples are affixed to the rigid footstalk of a large Epistylis.
Although Stein * failed to detect in the examples examined by him the presence of
fine vibratile cilia on the general cuticular surface, he reports the existence, towards
the anterior extremity, of fine, scattered, hair-like setae, which appear to assist in
maintaining the animalcule in its extended state, and are apparently identical in
character with the similar structures present in certain species of Stentor and
Chatospira. The record of the existence of these setae must be accepted as addi-
tional and important evidence in support of the Heterotrichous affinities of the
genus Tintinnidium and its allies, as advocated in this volume.

Tintinnidium semiciliatus, Sterki sp. PL. XXXI. FIGS. 6 AND 7.

Lorica subcylindrical, mucilaginous, flocculent and semi-opaque, through
the more or less abundant incorporation of vegetable debris, about three
times as long as broad ; enclosed animalcule conical or pyriform, truncate
and widest anteriorly, tapering posteriorly, and there continued in the form
of a slender, retractile pedicle, which equals the body in length and attaches
it to the bottom of the lorica ; cilia of the adoral wreath very large
and stout, flattened or lamellate, apparently pectinate at their distal
extremities ; the peristome-border enclosing an inner circlet of shorter and
finer simple cilia ; cuticular cilia limited to the anterior region of the body ;
oral cleft conspicuous, infundibuliform, produced backwards to a distance of
about one-third of the length of the entire body, associated with a movable
lip- or tongue-like organ ; contractile vesicle single, spherical, situated near
the termination of the oral cleft ; endoplast ovate, with a posteriorly
enclosed endoplastule, located on the opposite side and a little posterior to
the contractile vesicle ; adoral cilia only, during full extension, projecting
beyond the surface of the lorica. Length of body without the pedicle or
adoral cilia 1-625" to 1-416". HAB. — Fresh water, attached to Conferva.

This species is referred by Sterki f to the genus Tintinnus ; its distinctness
from Tintinnus (Tintinnidiuni) fluviatilis being, as he maintains, manifested in the
limited anterior distribution of the cuticular cilia, and in the peculiar character of
those forming the adoral wreath. These last-named appendages, according to
Sterki, are not simply cirrose, as with most ordinary Heterotricha, but are flattened
and lamellate, and thus coincide in structure with the so-called " membranellae," of
which, in accordance with the investigations of this authority, the homologous adoral
system of the Oxytrichidae is composed. Like the corresponding appendages of this
last-named group, they are inserted basally deep within the substance of the cortex, and
are further complicated by being split up in a laciniate or pectinate manner at their
free or distal end. Such a pectinate aspect is presented in the illustration reproduced
at PI. XXVIII. Fig. 7 ; but it would seem to be an open question whether or not
such delineation represents the optical aspect only of two or more concentric ciliary
circlets, and which, as they exist in many Peritrichous forms, have been frequently
depicted incorrectly as possessing a similar complex pectinate contour. Sterki,
nevertheless, is so satisfied as to the accuracy of his interpretation of these structures
as to give a drawing of an isolated pectinate cirrus, and reports that from fifteen to
twenty of these elements are associated in the complete series. While normally found
attached within their mucilaginous loricae, the animalcules of this species are capable

* « Infusionsthiere,' Abth. ii., 1867, p. 152.

t 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxxii., 1879.

GENUS VASICOLA—STROMBIDINOPSIS. 613

at will of severing such attachment, and swimming freely in the water. The pedicle
under such conditions is entirely retracted, and the body, as shown in the figure
last quoted, presents an evenly ovate contour. Multiplication by transverse fission
was observed, the process being preceded, as in Tintinnus urnula^ by the develop-
ment of a new and smaller adoral fascicle of cilia toward the posterior region of the
lateral border. Since Stein has, as above mentioned, recorded the presence of fine
hair-like setae towards the anterior region of Tintinniditim fluviatilis, it would seem
to be by no means improbable that the present form may eventually prove to be
but a synonym of that type.

GENUS III. VASICOLA, Tatem.

Animalcules more or less ovate, elastic and changeable in form, inhabit-
ing adherent, transparent loricae, within the cavities of which they remain
freely suspended, and from out of which they emerge at will ; oral aperture
at the anterior extremity, surrounded by a circlet of long cirrate cilia ; anal
aperture postero-terminal ; cilia of the general cuticular surface equal in
size, evenly distributed.

Vasicola ciliata, Tatem. PL. XXX. FIGS. 27 AND 28.

Lorica hyaline, erect, shortly flask-shaped, about twice as high as broad,
truncate posteriorly, slightly widest centrally, narrowing anteriorly into a
short, wide neck, its surface finely corrugate transversely ; animalcule ovate
or pyriform, filling the greater portion of the cavity of the lorica, the oral
orifice in extension usually level with the front border of the lorica, the
longer oral cilia springing from a more prominent raised lip or peristome ;
cuticular cilia fine, evenly distributed ; parenchyma usually enclosing
numerous light, claret-coloured food-globules. Length of body 1-180",
height of lorica 1-150".

HAB. — Pond water with decaying animal and vegetable matter.

No reference is made by Mr. Tatem in his description of this type * to the
presence of either an endoplast or contractile vesicle, the exact form and posi-
tion of the oral aperture being left in similar uncertainty. While under examination
the animalcules were found to be exceedingly impatient of restraint, usually issuing
from their loricae, and swimming freely in the water soon after their transfer to the
stage of the microscope. The ingestion of food-particles, including chiefly vibriones,
monads, and minute fragments of decaying vegetation, was abundantly observed,
as also on repeated occasions the increase of the animalcules within their loricae by
transverse fission. The brilliant colour of the food-globules, recorded in the fore-
going diagnosis, is not conspicuous until after their retention for some little time
within the substance of the parenchyma, and is, as suggested by Mr. Tatem, in
all probability attributable to the chemical action of the assimilative process. A
somewhat analogous coloration of the incepted food-particles has been already
observed to take place in relationship with certain species of the genus Nassula.

GENUS IV. STROMBIDINOPSIS, S. K.

(Strombidium ; opsis, like.)

Animalcules free-swimming, illoricate, ovate or pyriform, persistent in
shape ; peristomal cilia enclosing the entire frontal border, consisting of a
spiral wreath of one or more turns of long, powerful, cirrose cilia ; the whole
* ' Monthly Microscopical Journal,' vol. i. p. 117, 1869.

6 14 ORDER HETEROTRICHA.

surface of the body clothed with short, fine, vibratile cilia; contractile
vesicle posteriorly located.

The animalcules of this genus closely resemble those of the Peritrichous genus
Strombidium, but are to be distinguished from them by the fine ciliation of the
entire general surface of the body, and which, corresponding with that of Stentor or
Tintinnus, necessitates its relegation to the Heterotricha. The only species so far
observed is an inhabitant of fresh water.

Strombidinopsis gyrans, S. K. PL. XXXI. FIG. 29.

Animalcule elongate-ovate, about twice as long as broad, the anterior
margin truncate, the posterior extremity conical; cilia of the peristome
very strong and powerful, bent outwards, their length equal to that of
the entire body, forming a spiral wreath of rather more than one turn,
which commences at some little distance from the anterior margin ; its
left limb or extremity descending into the oral fossa, which is further con-
tinued to the centre of the body as a distinct pharyngeal passage ; cilia of
the cuticular surface very fine and short. Length of body 1-350".

HAB. — Pond water.

The animalcules forming the type of this species were met with in a pond con-
taining Myriophyllum and other aquatic plants, obtained from the neighbourhood of
Stoke Newington, London, in the month of February, 1874. The extremely long
outward-bent peristomal cilia, taken together with the ovate form of the body,
convey to this species an aspect not unlike that of a miniature shuttlecock. Its
movements in the water are extremely vigorous, and difficult to follow, consisting of
a swift gyratory motion, interrupted by rapid darlings to and fro across the field of
view.

Fam. V. TRICHODINOPSID-2B, S. K.

Animalcules free-swimming, persistent in shape, illoricate, posterior
border discoidal, acetabuliform, and adherent at will ; oral aperture sub-
terminal, approached by a spiral fringe of larger adoral cilia; general
cuticular surface finely ciliate throughout.

GENUS I. TRICHODINOPSIS, C. & L.

Animalcules freely movable, of more or less conical outline, having an
anterior adoral ciliary system and posterior adhesive sucking-disc, streng-
thened with a horny ring, similar to that of Trichodina, but the entire sur-
face of the body covered with fine vibratile cilia. Occurring as parasites
or commensals upon various aquatic Mollusca.

Trichodinopsis paradoxa, C. & L. PL. XXXI. FIGS. 39-43-

Body conical or cap-shaped, slightly curved, gradually tapering from the
broadly expanded base to the bluntly pointed anterior extremity ; the
posterior sucking-disc occupying about two-thirds only of the diameter of
the basal region, slightly eccentric ; ciliary zone surrounding this structure
longer and stronger than those of the oral region or general cuticular
surface ; interior corneous ring having no denticulations, but spirally striate

GENUS CODONELLA. 615

or plicate ; cilia of the general surface long and fine, presenting a tufted
or matted aspect, all directed towards the anterior extremity ; endoplast
laminate, nodular ; contractile vesicle single, spherical, anteriorly situated.
Length when extended 1-190".

HAB. — Fresh water, parasitic within the intestinal and pulmonary
cavities of various species of Cyclostoma. Geneva (C. & L.).

Claparede and Lachmann, the discoverers of this remarkable form — which,
excepting for the presence of the fine cuticular cilia, closely resembles a Trichodina
— have recorded the existence, within its oral cavity, of two transparent triangular
plates of considerable size, but whose nature and use they did not succeed in
determining. They likewise observed in close proximity to and immediately above
the posterior sucker a solid cap-shaped body, to which might possibly be attributed
the function of a muscular apparatus for the elevation or depression of the subjacent
disc. The movements of the cilia of the general surface of the body are referred to as
exhibiting a tufted aspect and elegant undulating action resembling that of Opalina,
Conckophthirus, and Plagiotoma. The species here described was found in countless
numbers within the intestinal and pulmonary cavities of Cyclostoma elegans ; a
further investigation among other aquatic Mollusca will probably reveal the
existence of many closely related forms. Through the intermedium of Trichodinopsis
the Heterotrichous order is clearly connected with that of the Peritricha, as
represented by Trichodina and its allies.

Fam. VI. CODONELLID.2E, S. K.

Animalcules free-swimming, conical or elongate, inhabiting an indurated
sheath or lorica, to the inner wall of which they are attached by the more
attenuate posterior extremity; oral aperture terminal, surrounded by an
outer circle of long, flexible, tentaculiform cilia, and an inner circlet of
shorter, cirrate cilia or lappet-like appendages.

The animalcules of this small family group are to be recognized by the presence
of the long tentacle-like cilia which form an outer fringe around the frontal border,
a type of structure which recurs again, however, in the smooth-bodied and conse-
quently Peritrichous genus Dictyocysta. Floating mouth downwards with these
tentaculiform appendages actively deployed in various directions, the resemblance of
these elegant Infusoria to minute Medusae is very striking. All the representatives of
this group as at present known are essentially pelagic.

GENUS I. CODONELLA, Haeckel.

Animalcules conical or trumpet-shaped, solitary, free-swimming, highly
contractile, inhabiting a helmet- or bell-shaped lorica, to which they are
attached by their posterior extremity; the anterior region truncate or
excavate, forming a circular peristome having an outer fringe of about
twenty long, tentacle-like cilia, and an inner collar-like border or frill, which
bears an equal number of slender, lappet-like appendages ; entire cuticular
surface clothed with fine, vibratile cilia ; lorica imperforate, of chitinous
consistence, sometimes sculptured or mixed with granular foreign sub-
stances. HAB. — Salt water, pelagic.

The several species referred to this genus were originally discovered by
Professor Haeckel in the Mediterranean, and described by him in an article

6l6 ORDER HETEROTRICHA.

" Ueber einige neue pelagische Infusorien," contributed to the ' Jenaische Zeitschrift '
for the year 1873.

Codonella galea, Hkl. PL. XXXI. FIGS. 32 AND 33.

Lorica helmet-shaped, slightly longer than broad, rounded and inflated
posteriorly, expanding at the frontal margin, constricted behind this region,
its substance verrucose, transparent anteriorly, apparently tesselated through
subdivision into regular polygonal areas, each of which encloses a minute,
siliceous (?) particle ; animalcule twice the length of the lorica when ex-
tended, dilated anteriorly to a width equal to or surpassing the aperture of
that structure, entirely filling the lorica when retracted; tentacular cilia
equalling the lorica in length ; inner membranous border or collar bearing
the lappet-like appendages, shallow, not exceeding in depth the length of
the lappets ; colour golden yellow ; endoplast band-like, curved, longitudi-
nally disposed; contractile vesicle posteriorly located. Length of lorica
1-250". HAB. — Saltwater: Messina and Lanzarote (Haeckel).

The lorica of this species corresponds so remarkably in shape and structure
with that of Tintinnus lagenula, that, compared in their uninhabited condition, it
is scarcely possible to separate the two. The animalcule of this last-named type,
as figured by Claparede and Lachmann, appears, however, to exhibit no essential
deviation from the ordinary members of the genus to which it is allocated, though at
the same time there would seem to be an indication of an inner circular peristomal
border corresponding with the membranous collar of the present species, but showing
no trace of the lappet-like appendages.

Codonella orthoceras, Hkl. PL. XXXI. FIG. 38.

Lorica elongate, conical, about two and a half times as long as broad,
tapering backwards from the wide oral aperture towards the sharply
pointed posterior extremity, but interrupted in the posterior half by a
globose inflation ; the posterior half rough and coarsely nodular, the anterior
smooth and finely annulate transversely ; animalcule when contracted
retreating to the inflated posterior region of the lorica. Length of lorica
1-125". HAB. — Salt water : Messina.

Haeckel considers the Tintinnus cinctus of Claparede and Lachmann, PI. XXXI.
Fig. 10, of which the lorica only has been observed, as probably closely allied to, if
not identical with this form. Its contour and structure, on comparing the two, is
found, however, to be too distinct for the admission of their absolute identity. In
T. cinctus the lorica, with the exception of the abruptly dilated oral aperture and
distinct tooth-like posterior termination, is cylindrical throughout, smooth, and
delicately annulate transversely from one end to the other. It is at the same time
possible that this form, in common with many others referred to in the genus
Tintinnus by the authorities quoted, on the strength only of the contour and struc-
ture of the lorica, will, when the enclosed animalcule is known, have to be referred
to the present or some other equally distinct pelagic genus.

Codonella campanella, Hkl. PL. XXXI. FIGS. 34-37.

Lorica bell- or helmet-shaped, about one and a half times as long as
broad, the posterior extremity produced into a long, subulate, conical point,
the anterior border widely dilated, transversely annulate throughout, but

GENUS TINTINNOPSIS. 617

this ornamentation concealed in the posterior region through the incor-
poration of coarsely nodular foreign particles ; animalcule as in C. galea,
but with a relatively deeper lappet-bearing membranous collar. Length of
lorica 1-170". HAB. — Saltwater: Lanzarote (Haeckel).

Professor Haeckel proposes to identify this species with the Tintinnus cam-
panula of Claparede and Lachmann. The animalcule of that type, as figured by
the Swiss authorities, however, presents the essential characters of an ordinary
Tintinnus, possessing a shuttlecock-like oral wreath of stout vibratile cilia that
cannot be consistently compared with the long, flexible, tentacle-like appendages
of Haeckel's Codonella. The lorica, again, is coarsely granular throughout, and
presents no trace of transverse annulation. Spherical, spore-like bodies, varying
in number from ten to twenty, were observed within the parenchyma of this species
by Haeckel on various occasions, and in one instance some fully developed embryos.
These germs, when liberated, were, as represented in the accompanying illustration,
PI. XXX. Fig. 36, of ovate form, finely ciliate throughout, and contained a central
band-like endoplast and posteriorly located contractile vesicle.

GENUS II. TINTINNOPSIS, Stein.

Animalcules campanulate or pyriform, attached posteriorly by a
slender, retractile pedicle within a membraneous free-floating sheath or
lorica, this lorica frequently enclosing sand-grains or other adventitious
particles ; peristomal cilia forming two complete and independent ciliary
circlets, those of the outer series being flexible and tentaculiform, those
of the inner one short and cirrose ; general surface of the body traversed
longitudinally from one end to the other by rows of short cilia, between
which intervene bare interspaces of considerable extent. Habits pelagic.

The only type of this genus yet observed is an inhabitant of salt-water. As
pointed out by Stein,* the peculiar band-like distribution of the cilia upon the
general surface of the body, essentially distinguishes it from Tintinnus, which he
regards as its most near ally, placing the two, indeed, in one family group. The
peculiar character of the outer series of oral or peristomal cilia is, however, entirely
different from what obtains in that genus, and corresponds more closely with what
is met with in Haeckel's recently described genera Codonella and Dictyocysta.
Haeckel, when referring to the genus Tintinnopsis, in his account of these two
last-named types, inadvertently quotes Stein as embodying as its diagnostic cha-
racter the presence of fine cilia throughout the cuticular surface in place of their
restriction to well-marked longitudinal bands, and further misrepresents the universal
distribution of these cilia in the one case and their entire absence in the other as
the essential distinction between the two genera Tintinnopsis and Tintinnus. In
this latter instance he simply reproduces Stein's interpretation of the characteristics
of the genus Tintinnus, which, as already explained, do not harmonize with the
results obtained through the more extensive investigation of this group made by
Claparede and Lachmann.

Tintinnopsis beroidea, Stein.

Lorica helmet- or thimble-shaped, the anterior margin widest, slightly
everted ; pointed posteriorly, composed of a transparent parchment-like
substance, enclosing numerous angular, dissimilar, siliceous particles ; body
of animalcule pear-shaped ; peristome bearing an outer and even circle of

* « Infusionsthiere,' Abth. ii., p. 154, 1867.

6 1 8 ORDER HE TERO T RICH A .

long, stout, widely separated cilia, and an inner spiral wreath of fine, closely
set shorter ones ; cilia of the general cuticular surface short and fine,
arranged in widely separated longitudinal rows ; endoplast linear, curved,
anteriorly located ; contractile vesicle situated at a short distance from the
posterior extremity. Dimensions unrecorded.
HAB. — Salt water : Baltic Sea.

According to Stein's observation the animalcules of this species become readily
detached from their loricae, and withdrawing the stem portion within the general
substance of the body, swim freely in the water. The outer circle of long and
widely separated peristomal cilia was frequently observed to be flexed backwards,
reaching at such times to a distance of one-third of the total length of the body from
the posterior extremity. These structures in their great length and flexibility would
appear to closely resemble the tentaculiform cilia of Codonella and Dictyocysta,
the lorica at the same time closely corresponding with that of Codonella campanella.
The specific title bestowed on this type by its discoverer bears reference to the
superficial likeness of the surface bands of cilia in both aspect and distribution
to those of a Beroe.

Fam. VII. CALCEOLIDJB, S. K.

Animalcules free-swimming, illoricate, ovate or pyriform, persistent
in shape ; general cuticular surface entirely ciliate, the body encircled by
one or two zone-like grooves and girdles of larger cirrate cilia; the oral
aperture ventral, perforating one of the equatorial grooves of cilia ; a
closely adpressed fa'scicle of long flexible setose cilia, presenting the aspect
of a stylate caudal appendage, projecting backwards from behind the
oral aperture.

GENUS I. CALCEOLUS, Diesing.

Animalcules free-swimming, unsymmetrical, obliquely pyriform, per-
sistent in shape, but not encuirassed ; cuticular surface finely ciliate
throughout, two groove-like channels encircling the body, one or both of
which give origin to a wreath of larger cilia than those of the cuticular
surface ; oral aperture ventral, situated in the posterior of the two trans-
verse annular grooves, followed by a tubular pharynx ; a tail-like fascicle
of long setose cilia, usually held bound to one another, and resembling a
single stylate process, projecting backwards from behind the mouth ; endo-
plast and contractile vesicle posteriorly located.

This genus is instituted by Diesing * for the form described that same year by
Professor H. James-Clark under the title of Peridinium cypripedium. Regarding, in
common with the last-named authority, the fascicle of setose cilia forming the caudal
appendage as an ordinary flagellum, Diesing has placed his newly created genus
among other Cilio-flagellate animalcules midway between Mallomonas and Proro-
centrum. From this low position in the infusorial scale it is here proposed to
advance it to one among the Heterotricha corresponding closely with that occupied
by Urocentrum in the division of the Peritricha.

' Revision der Prothelminthen,' p. 379, 1865.

GENUS CALCEOLUS. 619

Calceolus cypripedium, J.-Clark sp. PL. XXXII. FIGS. 23 AND 24.

Body obliquely pyriform, widest anteriorly, hollowed on the ventral side
by a broad longitudinal depression, which commencing at a little distance
from the larger and rounded anterior end extends in a straight line to the
more attenuate posterior extremity ; encircled by two annular furrows, the
anterior and narrower one bearing a wreath of long powerful locomotive
cirri, the whole body from this point backwards clothed with finer vibratile
cilia, these more crowded and conspicuous on the posterior furrow, the
ventral surface of which is perforated by the oral aperture. A fascicle of
closely approximated setose cilia, presenting in their agglomerate condition
the aspect of a single flexible caudal appendage, originating from the
posterior furrow at a little distance behind the mouth, and projecting
beyond the posterior extremity to an extent equal in length to that of one-
third of the whole body. Contractile vesicle large, spherical in diastole,
situated centrally close to the posterior extremity ; endoplast band-like,
curved, located immediately above the contractile vesicle, its two extre-
mities descending and embracing that structure on each side. Length of
body 1-300" to 1-150". HAB. — Fresh water. Colour, light brown.

Although introduced by H. James-Clark* as a representative of the genus
Peridinium, there can be little or no doubt, as first pointed out by Stein, that the true
place of this species is much nearer to that of Urocentrum turbo. In general contour
and in habits it in fact corresponds so closely with this type as to be apparently
referable to the same generic group. The one distinctive character, however,
afforded by the complete ciliation, with the exception of the anterior skull-cap-
shaped border, of the general cuticular surface, necessitates its isolation from the
typical smooth-bodied Peritricha. While thus separated, it may at the same time be
said to represent one of the most conspicuous annectant forms between the two orders
of the Heterotricha and Peritricha, and to exhibit the same relationship with reference
to the genus Urocentrum as is held by Trichodinopsis and Strombidinopsis respectively
with regard to the genera Trichodina and Strombidium. The movements of this
animalcule in the water accord entirely with those of Urocentrum turbo, consisting
chiefly of a vigorous rotatory motion to and fro on its long axis, it being often
temporarily attached under such circumstances to some solid substance by the
extremity of its adhesive caudal appendage, and upon which it revolves as though
on a pivot. This sedentary condition is in like manner frequently changed for a
more active natatory one, and in which it darts in a straight line from one place to
another with amazing swiftness, tacking, as it were, now and then to one side or
the other, and apparently utilizing its posterior caudal fascicle after the manner of a
rudder. Multiplication by transverse fission is the only reproductive phenomenon
that has so far been observed with reference to this type. The contractile vesicle
was observed by Professor Clark to assume a somewhat irregular outline between
diastole and systole, but does not appear to possess distinct lateral sinuses as has
been observed by the present author of Urocentrum turbo.

* ' Proceedings of the American Academy of Science,' February 1865.

620 ORDER PERITRICHA.

Order III. PERITRICHA, Stein.

Animalcules free-swimming or attached, solitary or united in social
colonies, often in the latter instance forming branched tree-like growths ;
oral aperture terminal or subterminal ; ciliary system consisting of an
anterior, circular or spiral, adoral wreath with occasionally one or more
supplementary equatorial or postero-terminal locomotive circlets, the
remaining cuticular surface entirely smooth ; in those instances in which
the adoral wreath takes a spiral form the right limb more usually involute
and descending into the oral fossa ; anal aperture posteriorly located or
debouching upon the vestibular or oral fossa ; endoplast mostly elongate,
band-like; multiplying by longitudinal or transverse fission. Inhabiting
salt and fresh water. Trichocysts rare.

Excepting for the presence of one or two aberrant types, the representatives of
the Peritricha constitute collectively the most sharply defined and natural group of
the class Ciliata. The smooth rounded bodies and restriction of the cilia to a circular
or spiral anterior wreath, and an occasional median or posterior circlet affords
a ready clue to their recognition, while the fixed and sedentary life led by the larger
proportion of its members affords facilities for their examination met with in no
other infusional section. In addition to the very substantial augmentation of the
number of generic groups embodied in this treatise, a considerable departure is
made in the subdivision of this order into families, as here pursued, from the plan
adopted by Stein in the second volume of his ' Organismus/ and reproduced at
page 210 of vol. i. Among the more important alterations accomplished in this
direction, Tintinnus and its allies have been removed to the preceding order of the
Heterotricha, the fine ciliation of their entire cuticular surface, as demonstrated
through the researches of Claparede and Lachmann, precluding their further reten-
tion in that of the present order. Through the Peritrichous Strombidium and
Heterotrichous Strombidinopsis the more remote affinity of Tintinnus to the typical
Peritricha is, however, doubtless indicated ; a similar amalgamation of the two
orders being likewise apparently brought about between the three genera Codonella,
Dictyocysta, and Petalotricha. The family of the Vorticellidae is here made to include
the three sections of equivalent value comprised by Stein under the respective titles
of the Vorticellina, Ophrydina, and Spirochonina ; all of these, as shown in the
succeeding descriptions, passing from one to the other by easy stages of gradation,
and preserving at the outside distinctive features sufficient only for their separation
into groups holding the position of sub-families. Among the more aberrant types
included in the order Peritricha, the three genera Torquatella, Actinobolus, and
Urocentrum may be especially alluded to ; the abnormal features of these forms and
the question of their more immediate apparent affinities being discussed at length in
their generic or specific description. One of these, Urocentrum, corresponding
closely in general form and structure with the entirely ciliate Calceolus, may be
cited as an additional annectant form between the two orders of the Heterotricha
and Peritricha.

By most authorities the order of the Peritricha has been regarded as typifying
the highest and most specialized group of the Infusoria Ciliata. The present
author, however, is not disposed to coincide with this view. Specialization appa-
rently reaches its zenith of development in the succeeding order of the Hypotricha,
in which the cilia or their modified homologues are differentiated and made sub-
servient to the performance of a variety of functions to an extent that is not
found among any other representatives of the sub-kingdom Protozoa. Evi-
dence in support of the lower comparative position occupied by the Peritricha

GENUS TORQUATELLA. 621

as here maintained is further afforded by the marked sedentary and vegetative
mode of growth exhibited by so large a proportion of its members, and yet more
noticeably with reference to the phenomena of reproduction as elicited by the light
of recent investigation. In this last-named connection it has been abundantly
shown that the process of conjugation or genetic union is accomplished through the
complete and permanent fusion of two independent zooids, as obtains among the
lower sections of the Flagellata and unicellular Protophytes, and which thus differs
essentially from the temporary union only of the sexually matured zooids which
occurs amongst the Hypotricha and even many Holotricha, and among which, con-
sequently, a far nearer approach is made to the typical mode of sexual concourse
that subsists among the higher zoologic groups.

A tabular form of the family and generic groups of the Peritricha, as delimited
in this volume, is given overleaf.

Fam. I. TORQUATELLID-ffi, S. K.

Animalcules free-swimming, illoricate, more or less ovate ; the anterior
ciliary wreath replaced by a membranous extensile and contractile collar-
like structure, which is perforated centrally by the oral aperture.

The relegation of the single type included in this family group to the Peritricha
is effected with some diffidence, it possessing, perhaps, an equal claim for recog-
nition as the representative of a new and distinct order. Regarding, however,
the terminal frill or collar-like membrane as an incipient or only partially developed
fringe of cilia, its affinity to the more ordinary members of the section in which it is
here placed is apparent. A similar though at the same time transitory assumption
by the adoral cilia of a membraniform character is especially alluded to in this volume
in the case of Stentor and Aspidisca, while in many Hypotricha, Heterotricha, and
Holotricha such a membrane permanently fills the place otherwise occupied by the
adoral or pre-oral fringe. On the other hand, the membraniform collar of Torquaiella
may perhaps be regarded as homologous with the umbrella-like peristomal mem-
brane of Codondla, or indeed as an exaggerated development of the peristome of
such a typical Peritrichan as Vorticdla patdlina, as represented at PI. XXXIV.
Fig. 22.

GENUS I. TORQUATELLA, Lankester.

Animalcules free-swimming, more or less ovate, entirely devoid of cilia,
but possessing at the anterior extremity a projecting plicate membranous
frill, by the more or less vigorous expansion and contraction of which
motion through the water is effected, and food-particles brought within
reach of the mouth ; oral aperture situated within the centre and at the
base of the projecting frill, guarded by a tongue-shaped valve or velum.

Torquatella typica, Lankester. PL. XXXII. FIGS. 32-34.

Body elongate-ovate, nearly twice as long as broad, rounded posteriorly ;
the anterior membranous frill highly expansile, its front margin abruptly
truncate or emarginate, its surface obliquely plicate. Dimensions unre-
corded. HAB. — Salt-water, Mediterranean.

This remarkable animalcule was met with on one occasion only by Professor
E. Ray Lankester at Naples in association with a mass of eggs of Terebella in a
decaying state, and fragments of which had been freely incepted. The anterior

622

CILIA TA-PERITRICHA.

GENUS.
Torquatella.

Dictyocysta.
Petalotricha.

Actinobolus.

Halteria.
Strombidium.

Mesodinium.

Acarella.
A rachnidium.
Didinium.

Gyrocoris.
Urocentrum.
Telotrochidium,

Ophryoscolex.
Entodinium.
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II. DlCTYOCYSTID^E.
Animalcules loricate.,

III. ACTINOBOLID^E.

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V. GYROCORID^;.

Animalcules pyriform ; oral apertur
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VI. URCEOLARIID^;.
Animalcules turbinate or discoidal
oral aperture subterminal ; posterio
extremity acetabuliform, adhesive
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VII. OPHRYOSCOLECIDjE.

Animalcules ovate or elongate ; ora
aperture terminal, associated with :
spiral adoral wreath of cilia ; posterio
extremity bearing one or more stylat<
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C/Z//2 TA-PERITRICHA.

623

1

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Spirochona.

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Rhabdostyla.

Pyxidium.
Vorticella.

Carchesium.
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Opercularia.

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624 ORDER PERITRICHA.

membranous collar, whose contour is compared by its discoverer* to that of an
Elizabethan frill, is described as being in a state of constant vibration, alternately
closing up and expanding with a twisting movement, and exhibiting the same
rapidity and regularity in this motion as do a series of cilia in a similar position.
The movements of the collar may in short be compared to those of a series of cilia
united throughout their length by a delicate membrane, progress through the water
being at the same time accomplished with the aid of this mechanism in a manner
closely analogous to the locomotion of the free-swimming Medusae. Unfortunately,
no note was taken at the time of the position or character of the endoplast or
contractile vesicle, nor of the reproductive phenomena.

Fam. II. DICTYOCYSTIDJE, Haeckel.

Animalcules free-swimming, secreting and inhabiting siliceous or cor-
neous, fenestrate or imperforate, helmet- or bell-shaped loricae ; peristome
terminal, subcircular, associated with a more or less complex ciliary
system ; oral aperture eccentric, cuticular cilia entirely absent.

The family of the Dictyocystidae was originally instituted by Professor Haeckel t
for the reception only of Ehrenberg's genus Dictyocysta. To this is here added the
new generic group Petalotricha, including the so-called Tintinnus ampulla and Tin-
tinnus spiralis of Professor Fol, which differ from the true Tintinni, but resemble
Dictyocysta, in the non-ciliation of their cuticular surface and in the compound
character of the peristomal appendages.

GENUS I. DICTYOCYSTA, Ehrenberg.

Animalcules solitary, free-swimming, extensile and contractile, excreting
and inhabiting more or less perforated, bell- or helmet-shaped, siliceous
loricae ; the enclosed body globular or campanulate, attached to or
dependent from the posterior extremity of the lorica, and protruding, when
extended, to some distance beyond its aperture, the oral or distal extremity
truncate, circular, bearing an outer fringe of long, tentacle-like cilia, and an
inner circle of short, thick, uncinate cilia or cirri ; oral aperture eccentric,
located close to the inner circle of uncinate cilia ; general cuticular surface
entirely smooth. HAB. — Salt water, pelagic.

The animalcules of this genus closely resemble those of Codonella previously
described, and but for the absence of fine cilia upon the general cuticular surface
would be necessarily placed in the same family. The singular anterior fringe
of lappet-like appendages is likewise wanting in Dictyocysta, being replaced by
a circlet of cirrose adoral cilia, corresponding with those of the more ordinary
Peritricha. The beautiful perforated siliceous loricae of the various species are
scarcely to be distinguished from the tests of certain Polycistinas, and were indeed,
previous to the examination and report upon their living inhabitants by Professor
Haeckel, referred by Ehrenberg j to that Radiolarian group.

Dictyocysta cassis, Hkl. PL. XXXII. FIGS. 29-31.

Lorica helmet-shaped or inflated conical, about one and a half times
as long as broad, pointed posteriorly, gradually widening towards the

* ' Quarterly Journal of Microscopical Science,' vol. xiii., 1874.

f " Ueber einige neue pelagische Infusorien," ' Jenaische Zeitschrift,' Bd. vii., 1873.

\ ' Monatsbericht Berliner Akademie,' p. 236, 1854.

GENUS DICTYOCYSTA. 625

expanded anterior aperture ; perforations minute, polygonal, subequal, and
closely approximated ; animalcule elongate-conical, projecting some little
distance beyond the orifice of the lorica ; tentacular-like cilia nearly equal
in length to the extended body; contractile vesicle spherical, posteriorly
situated. Length of lorica 1-225".

HAB.— Salt water : Messina (Hkl.) ; British Channel, Falmouth (S.K.).

Among the examples of this species figured and described by Professor Haeckel,*
one was observed to contain about twenty spherical spore-like bodies, each of which
enclosed a conspicuous central endoplast. In July 1879, an empty lorica of this
type was obtained by the author in association with Tintinnus subulatus, Ceratium
fusus, and other pelagic forms, off the coast of Falmouth, mention of such capture
being recorded in the ' Midland Naturalist' for April 1880. As there intimated, its
occurrence at a station so considerably to the north of the apparent head-quarters
of this type, is a feature of some interest. Upon the grounds that the lorica in
this species is not actually perforated but simply pitted, Professor Folf has pro-
posed to make it the type of a new genus, Cyttarocysta. Such structural character,
however, is not regarded by the author to be sufficiently substantiated, or of sufficient
import as to render such subdivision desirable. This authority further dissents from
Professor Haeckel in declaring that the body of the animalcule does not gradually
taper off to its point of attachment as delineated in the accompanying figure, but
that it is subdivided into a distinct inflated body and an attenuate stalk-like portion,
as occurs among many typical Tintlnni.

Dictyocysta mitra, Hkl. PI. XXXII. FIGS. 25 AND 26.

Lorica mitre-shaped, nearly as broad as long, widest centrally, obtusely
pointed posteriorly, slightly constricted immediately behind the slightly
everted anterior aperture, its walls pierced by numerous rounded perfora-
tions of various sizes, including a single series of about five larger somewhat
quadrate perforations arranged in a circle close to the anterior border, and
about four transverse circles of largish rounded perforations between this
and the posterior extremity; various smaller loculi interspersed among
the larger ones and developed exclusively towards the posterior extremity ;
animalcule campanulate, subglobose ; tentaculate cilia equal to or sur-
passing the body in length ; contractile vesicle posteriorly located ; endoplast
band-like, curved, transversely placed. Length of lorica 1-375".

HAB. — Salt water : Messina and Lanzarote (Hkl.).

Professor Fol considers this species to be synonymous with the Dictyocysta elegans
of Ehrenberg.

Dictyocysta templum, Hkl. PI. XXXI. FIG. 27.

Lorica inflated, cupola-shaped or hemispherical, nearly as broad as long,
pointed posteriorly, the anterior aperture dilated ; fenestrations of variable
dimensions ; seven exceedingly large, equal sized, irregular quadrate areas,
separated from one another only by slender, obliquely parallel, pillar-like
trabeculse, bordering the frontal margin ; seven roundly polygonal

* " Neue pelagische Infusorien," ' Jenaische Zeitschrift,' Bd. vii., 1873.
t ' Archives des Sciences Physiques et Naturelles,' torn, v., 1881.

VOL. II. M

626 ORDER PERITRICHA.

fenestrae of about half the dimensions of those last-named, forming an
equatorial girdle round the centre of the lorica ; between the equatorial and
marginal series, a ring of fourteen still smaller, but considerably sized,
circular lacunae; the remaining surface of the lorica perforated by in-
numerable irregularly disposed fenestrae of rounded form and variable size,
few of which equal the dimensions of those of the smallest annular series.
Length 1-400". HAB. — Salt water : Messina and Lanzarote (Hkl.).

Dictyocysta tiara, Hkl. PL XXXII. FIG. 28.

Lorica elongate-conical, or tiara-shaped, over twice as long as broad ;
pointed posteriorly, inflated centrally, slightly constricted before expand-
ing outwards again to form the anterior opening ; ten large elliptical loop-
like fenestrae, equal in height to one-third of that of the entire lorica, and
separated from each other by slender trabeculae, bordering the frontal
margin ; a circlet of ten oval fenestrae of about half the dimensions of the
frontal series forming a zone round the centre of the lorica, and ten similar
shaped perforations of about one-quarter the size of the marginal series,
forming a circle between the equatorial girdle and the pointed posterior
extremity ; several smaller supplementary annular series and innumerable
irregularly shaped lacunae distributed through the remaining area of the
lorica. Length 1-250". HAB. — Salt-water: Lanzarote (Hkl.).

Dictyocysta elegans, Ehr.

Lorica oblong, urceolate, its frontal region narrowest, subcylindrical,
truncate, perforated by two rows of about eight large quadrangular fenestrae ;
the wider basal portion obtusely rounded, perforated by smaller irregularly
scattered, rounded lacunae. Length 1-480", breadth 1-576".

HAB. — Salt water : Newfoundland, among phosphorescent surface-
skimmings.

This species, while founded by Ehrenberg * on examples brought from the
vicinity of Newfoundland, is also identified by him with one of the many micro-
scopic organisms figured by Johannes Miiller many years previously,! and obtained
by him from the intestinal tract of the Echinoderm Alecto Europea. Excepting for
the relatively narrower diameter of the distal region of the lorica, this species as
recognized by Professor Fol, is scarcely to be distinguished from the Dictyocysta
mitra of Professor Haeckel.

Dictyocysta lepida, Ehr.

Lorica oblong, urceolate; distal region cylindrical, loosely reticulate, com-
prising a single series of nine circular perforations ; proximal portion sub-
globose, sparsely perforate. Length 1-400", breadth 1-576".

HAB. — Saltwater: Newfoundland.

* ' Monatsberichte der Berliner Akademie,' p. 236, 1854.

t " Ueber den Bau des Pentacrinus Caput-inedusce" ' Abhandlungen der Berliner Akademie,'
1841.

GENUS PETALOTRICHA. 627

Dictyocysta acuminata, Ehr.

Lorica oblong, campanulate, acuminate posteriorly ; the distal border
truncate, widely expanded, perforate by a series of long narrow lacunae.
Length 1-432", breadth 1-576".

HAB. — Salt water : Newfoundland, among phosphorescent surface-
skimmings.

GENUS II. PETALOTRICHA, S. K.

(Greek, petalon, petal ; trichos, hair.)

Animalcules free-swimming, excreting and inhabiting imperforate
corneous loricae ; enclosed body conical or campanulate, attached to the
fundus of the lorica by a retractile peduncle ; ciliary system restricted to
the excavate distal region, consisting of a series of larger marginal motor
cilia, which are developed upon petaloid or lappet-like prolongations of
the peristome-border, and an internal series of short vibratile cilia, which,
starting from the interior of the disc, follow about twenty curved lines
tangential to the margin of the peristome, and which are continuous at the
peripheiy with the external motor series ; oral aperture eccentric, continued
into a pouch-like pharynx, which stands out separately from the walls of
the body, and into which several of the rows of cilia of the disc are pro-
longed ; anal aperture located near the insertion of the peduncle. Inhabiting
salt water.

This genus is provisionally instituted by the author for the reception of the two
species referred to the genus Tintinnus by Professor Fol,* under the titles of
Tintinnus ampulla and 7! spiralis. The restriction of the cilia to the distal region,
added to the abnormal disposition of these appendages, separates these species in a
marked manner from the typical members of the genus as defined in this volume,
and apparently indicates their nearer zoological position to the genus previously
described.

Petalotricha ampulla, Fol. sp. WOODCUT, p. 628, FIGS, i AND 2.

Lorica ovoid, terminated posteriorly by a slight projection in the form
of a point, widely open above, where an expanded funnel-like portion is
superposed upon the ovoid part ; the widened portion composed of two
zones, of which the superior is more turned out than the inferior one ; a
slight circular projection, notched into the likeness of an arcade, developed
on the inner surface along the boundary between the two zones ; body of
animalcule apparently smooth ; peristomal cilia arranged in twenty-four
curved lines, produced from the interior towards the margin of the disc.
Length of lorica, 1-280".

HAB. — Salt water : Villefranche-sur-Mer.

The above diagnosis is reproduced verbatim from Professor Fol's description of
his so-called Tintinnus ampulla, to which is herewith appended an abstract of his
elaborate description of the oral and ciliary systems. With reference to the notched

* ' Archives des Sciences Physiques et Naturelles,' torn, v., 1881.

M

628

ORDER PERITRICHA.

petaloid modification of the peristomal border, it would seem to most nearly
approach Haeckel's genus Codonella. In, however, the possession of a distinct pha-
ryngeal pouch, which, in accordance with Professor Fol's delineation, Woodcut,
Fig. i, ph, stands out separate from the body like the gibbous pouch or spur of a
floral envelope, this type has no parallel among the entire infusorial series. Professor
Fol's general account of this new type runs as follows : —

FIGS, i and a. Petalotricha. ampulla, Fol sp. i. Lateral aspect, showing at//4 pharyngeal pouch, X 300. 2. Two
conjugating zooids viewed from above; or, oral aperture ; ep, raised boss or epistome.
FIG. 3. Petalotricha spiralis, Fol sp., X 200. {After Professor Fol.)

" The superior discoidal extremity or peristome, when the animal is in a state
of perfect extension, is placed a little obliquely with relation to the aperture of the
test. The disc itself, instead of being flat or slightly convex, as is the case in the
Vorticellina, is hollowed out like a saucer, and the vibratile cilia, instead of forming
a single row round the margin of the disc, are implanted in great number and in
several lines over the greater part of the surface. The arrangement of these vibratile
cilia is exceedingly curious and interesting, and deserves attention, the more because
it has not been described by any of the authors who have busied themselves with the
Tintinni. The whole margin of the disc is occupied by long and strong motor cilia,
which strike the water vigorously, and give the animal an exceedingly rapid recti-
linear movement of translation. It is thus, in fact, that the animals habitually swim;
but they can readily deviate from the direct line when they have to avoid an obstacle.
Moreover, the animal is constantly turning upon itself during its progress, which is
therefore comparable to that of a rifle ball. As soon as the great motor cilia com-
mence their action, they present the so-called phenomenon of rotation in a high
degree. The undulation is propagated from right to left, the observer being supposed
to be placed at the axis of the animal. The other cilia are arranged in parallel lines,
all curved in the same direction, and running from the margin of the disc or
peristome towards the mouth. In the present species, T. ampulla, twenty-four of
these lines were counted. The mouth occupying an eccentric position, or Fig. 2,
the lines which start from the margin nearest to that aperture are of course much
shorter than those which start from the more distant margin. There are, however,

GENUS PETALOTRICHA. 629

only a few lines of cilia that actually reach the entrance of the mouth, and these are
precisely the shortest ones. The others stop so as to leave the central part of the
disc naked. All the rows just mentioned are formed of thick, short, slightly recurved
cilia, scarcely attenuated at their free extremity, and only beating for moments.
Their length decreases regularly from the margin of the peristome, which bears the
thickest and longest, to the inner extremity of the line, which is formed of much
shorter and more slender cilia. On returning to the motor cilia to ascertain what
relation they bear to the cilia of the disc, it is noticeable, in the first instance, that
the margin of the peristome, viewed from its upper surface (Woodcut, Fig. 2), is not
simply rounded, but denticulate. The teeth resemble those of an ordinary saw, and
are all turned in the same direction, and this direction is precisely that towards
which the rows of short thick cilia deviate. Each of the rows indeed corresponds to
one of the denticulations in such a manner that it terminates at the base of the
longer side of the denticulation, or that which forms a tangent to the margin of the
disc. The arrangement once understood, it is easy to ascertain that the large motor
cilia are upon the longer margin of each denticulation, hence they do not form a
continuous circular or spiral line, but a broken line, the segments of which are only
simple continuations of the rows of short cilia."

" The entrance to the mouth, or Fig. 2, meets the surface of the disc obliquely,
the pharynx being directed towards the left, at the same time gradually contracting.
By looking at the animal in profile (Woodcut, Fig. i) it is easy to see that the
pharynx, ph, is lodged in a pouch-like lateral projection of the body of the Infusor.
A certain number of the rows of cilia of the disc descend into the pharynx and there
form a series of nearly straight parallel lines composed of extremely fine cilia. The
actual margin of the mouth is furnished with tolerably stout and long cilia which
beat energetically ; but I have not succeeded in ascertaining precisely what relation
may exist between these cilia and those just described in detail. All the rest of the
body was smooth ; at least, it is hardly probable that cilia, however fine they might be,
could have escaped my observation had they actually existed."

The position of either the endoplast or contractile vesicle was not determined by
Professor Fol. Several instances of conjugation were observed in which two
animalcules were intimately united to each other by their peristomal margins.

Petalotricha spiralis, Fol. WOODCUT, p. 628, FIG. 3.

Lorica greatly elongated, pointed, drawn out ; the posterior third nearly
cylindrical, very narrow, terminated by an acute point ; the anterior two-
thirds having the form of an elongated cone, slightly inflated ; near the orifice
a thickening in the form of a cushion projecting outwardly ; substance of
lorica composing two very distinct layers, presenting at the surface some
faintly marked and somewhat irregular striae, generally parallel, disposed
obliquely to the axis of the test, and describing very elongate dextrogyrous
spirals; small points arranged in spiral lines parallel to the striae, and
alternating with them ; the cushion that surrounds the orifice formed
solely by the outer layer ; animalcules short, peduncle much elongated,
attached at a considerable distance from the apex of the test, or even pre-
senting two points of attachment ; curved lines of peristomal cilia number-
ing about twenty ; body apparently smooth. Length of lorica 1-62".

HAB. — Salt water : Villefranche.

Described by Professor Fol under the title of Tintinnus spiralis.

630 ORDER PERITRICHA.

Fam. III. ACTINOBOLID-ffi, S. K.

Animalcules free-swimming, ovate or globose ; oral aperture terminal,
surrounded by a fringe of adoral cilia, supplemented by numerous retractile
tentaculiform appendages.

Although the tentaculiform appendages in the as yet single known animalcule
referred to this family are described by Stein as resembling those of the Acinetida —
between which and the Ciliata he regards it as an annectant type — it seems hardly
probable that such structures actually exist in company with a well-developed oral
aperture. It would seem more likely, on the other hand, that they find their homo-
logues in the retractile setae of Stentor, or in the springing-hairs of Halteria and
Mesodinium. To the family group embracing the two last-named generic forms
it is not improbable, indeed, that Actinobolus may have hereafter to be transferred.

GENUS I. ACTINOBOLUS, Stein.

Animalcules free-swimming, ovate or globular ; oral aperture perforating
the centre of the apical extremity, encircled by short even-sized cilia, among
which are scattered numerous thread-like tentacula capable of extension
or retraction within the substance of the parenchyma, like those of the
Acinetidae ; anal aperture postero-terminal ; endoplast and contractile
vesicle conspicuous.

Actinobolus radians, Stein.

Body irregularly ovate or subglobose, the anterior extremity produced
as a short nipple-shaped or snout-like projection pierced by the oral aper-
ture and bearing the oral cilia and retractile tentacula ; endoplast elongate,
cord-like, irregularly curved ; contractile vesicle large, spherical, postero-
terminal. Dimensions unrecorded.

HAB. — Fresh water, among Lemnce.

It is to be regretted that Stein has not published a more exhaustive account,
with an illustration, of this remarkable animalcule ; the only description at present
available for reference being a few lines in a footnote, p. 169 of the second volume
of his ' Organismus.' Although placed by him among the Holotricha, it is not stated
that the cuticular surface bears cilia throughout, those 'around the oral aperture
alone being mentioned.

Fam. IV. HALTERIID^E, Clap. & Lach.

Animalcules free-swimming, persistent in shape, more or less globose
or ovate, bearing a spiral or subcircular wreath of adoral or locomotive
cilia, these occasionally supplemented by a girdle of long hair -like
springing-setae ; oral aperture terminal, central or eccentric ; trichocysts
sometimes developed.

The several genera here united under the family title of the Halteriidae, while
harmonizing tolerably with one another in general contour and comportment, present
among themselves so considerable a variation in the composition of their oral and
ciliary systems, that their separation into more numerous, but less comprehensive,
groups of equivalent value, was at first determined. A closer study of them, how-

GENUS HALTERIA. 631

ever, has elicited that these several genera, although diverging considerably from
one point of view, approach each other so closely when regarded from another,
while in many cases, again, so imperfect a knowledge is as yet possessed of their
more essential structural details, that it has been considered desirable for the present
to keep them associated. The most important structural deviations exhibited by the
members of this family, as here defined, is manifested by Halteria and Strombidium,
with their eccentric oral aperture and spirally involute adoral fringe, as compared
with the four remaining genera, in which the oral aperture is perfectly central, and
more or less disconnected from the ciliary system. Even here, however, Mesodinium
corresponds so closely in its general structure and comportment with Halteria,
that the marine species M. pulex was unhesitatingly referred by Claparede and
Lachmann to that genus. By Stein both Didinium and Mesodinium are separated as
types of a distinct family — his Cyclodina; but, strangely enough, with these are
included by him an animalcule, Urocentrum turbo, with which they can scarcely
be said to possess a single point in common, and whose natural position is obviously
close to Gyrocoris, With but one or two exceptions all the members of the Hal-
teriidas are of exceedingly minute size, swift and restless in their movements, and
consequently form one of the as yet least perfectly investigated divisions of the
Peritrichous order.

GENUS I. HALTERIA, Dujardin.

Animalcules free-swimming, more or less globose ; oral aperture ter-
minal, eccentric, associated with a spiral or subcircular wreath of large
cirrose cilia ; a zone of long hair-like setae or springing-hairs developed
around the equatorial region, the sudden flexure of which appendages
enables the animalcules to progress through the water by a series of
leaping movements, in addition to their ordinary swimming motions.

The animalcules of this genus are easily recognized by their globose form and
peculiar movements in the water, which consist of a slow rolling or rotatory
motion, interrupted at short intervals by a sudden leap backwards or to one side. It
was originally supposed by Dujardin that their springing motions were effected by
the contraction of the setse in connection with some fulcrum of support ; as, how-
ever, the same motions may be readily observed when the animalcules are swimming
freely at a distance from any foreign bodies, this hypothesis becomes untenable,
and it is evident that the leaps are produced simply by the sudden reflex action of the
hair-like setse. By the above authority this central girdle of setse is also represented
as following an oblique direction; such interpretation, however, represents an
erroneous optical impression frequently produced as the animalcules rotate through
the water at various angles divergent from their longitudinal axes. The exact
position of the oral aperture and relationship of the associated adoral cilia has not
up to the present time been decisively determined, the restless and rapid motions
of the animalcules rendering these two points especially difficult to interpret. By
many writers the oral opening is described as perfectly central, and the accom-
panying cilia as forming an unbroken circular wreath. Claparede and Lachmann,
however, go so far as to report the existence on one side of the peristome of a small
notch-like interruption. The author's impression, derived from repeated examina-
tions of the cosmopolitan form, H. grandinella, is that this adoral wreath is neither
symmetrically circular nor interrupted in the simple manner above indicated, but
that the right-hand limb or extremity of this wreath is, at the apparent notch, curled
spirally inwards, and there descends into the oral aperture. This interpretation,
reproduced in the accompanying illustration of the species quoted, demonstrates, if
correct, the character of the peristome or adoral fringe in Halteria to agree with
that of Strombidium and the Vorticellidae, and to be the converse of what obtains in
Stentor and other Heterotricha. In these, as explained in a previous page, it is the
left limb of the adoral fringe that spirally encircles and descends into the oral fossa.

632 ORDER PERITRICHA.

Halteria grandinella, Miill. sp. PL. XXXII. FIGS. 35-38.

Body subglobose, transparent, .usually terminating posteriorly in a
somewhat narrower obtusely rounded point ; springing-setae very long and
fine, forming a central girdle, but not situated in an equatorial groove or
furrow, the circle of adoral cilia exhibiting at one point a short interruption
or spiral involution ; contractile vesicle and endoplast spherical, located
close to each other near the centre of the body. Length 1-1500" to 1-860".

HAB. — Pond water.

This species, while receiving its characteristic generic title from Dujardin, is
identical with the Trichoda and Trichodina grandinella of O. F. Miiller and Ehren-
berg. It is of common occurrence in pond water, and has been described and por-
trayed by almost all the earlier writers. With the exception, however, of those by
Claparede and Lachmann, none of these figures or descriptions given are to be
relied upon, all having misinterpreted the true form and structure of both the oral
ciliary wreath and that central girdle of setse by which the animalcule accomplishes
its leaping movements. As first shown^by Miiller, Halteria grandinella increases by
transverse fission, the process of separation into two of a single individual being
extremely rapid. When examining examples of this or< other species of the genus,
Claparede and Lachmann recommend the introduction upon the same slide of a few
suctorial Acinetae. Against these the Halterias are sure to strike while making
their characteristic bounds, and being immediately seized and held immovably, an
unprecedented opportunity is afforded for studying their structural characters. In
a gathering containing a large number of these animalcules recently collected in the
neighbourhood of St. Heliers, Jersey, the author found associated with them nume-
rous examples of a species of Urotricha closely allied to, if not identical with,
U. farcta. Their dimensions equalled about one-half that of the Halterias, while
their rolling and springing movements corresponded so closely with those of their
larger comrades, that it is considered highly probable by the author that Urotrich a
may eventually prove to be an immature or larval condition only of Halteria.

Halteria volvox, Eichwald sp. PL. XXXII. FIG. 39.

Contour of body as in H. grandinella, but rather larger ; leaping-hairs
taking the same form and position, but supplemented by an equatorial
zone of long, recurved, filamentous cilia. HAB. — Fresh water.

Claparede and Lachmann observed this species as here figured on one occasion
only, and refer it with some doubt to the Trichodina volvox described in Eichwald's
' Infusorienkunde Russland,' 1852.

Halteria viridis, From.

Body globose, anteriorly truncate, surface smooth, colour green ;
median circlet of setae very stout and conspicuous ; motion rotatory and
leaping. Length 1-1600". HAB. — Fresh water.

Halteria verrucosa, From.

Body subspherical, truncate anteriorly, acuminately pointed posteriorly,
having a central depression on one side which imparts to it a gibbous
contour ; colour green. Length 1-600". HAB. — Fresh water.

GENUS STROMBIDIUM. 633

Halteria lobata, From.

Body globose, the frontal margin projecting in the form of three raised
papillae ; colour green ; movements very swift. Length 1-800".
HAB. — Fresh water.

Supplementary Species.

As many as five additional species are added to the genus Halteria by De
Fromentel,* in none of which, however, with one exception, are the characters given
sufficiently distinct for separate specific recognition. This exceptional form, his
H. bipartita, is, however, not a Halteria, but apparently belongs to the genus Arach-
nidium. The Halteria pulex of Claparede and Lachmann is evidently referable to
Stein's genus Mesodinium.

GENUS II. STROMBIDIUM, C. & L.

Animalcules free-swimming, globose, or turbinate ; oral aperture termi-
nal, eccentric, associated with a spiral wreath of powerful, erect, cirrose
cilia ; no accessory springing-hairs ; endoplast and contractile vesicle
conspicuous. Inhabiting salt and fresh water.

The animalcules of Strombidium surpass those of Halteria in the restlessness
and rapidity of their movements, much difficulty consequently attending the inter-
pretation of the true nature of their oral system. Claparede and Lachmann have,
however, decided that the peristomal cirri in Strombidium turbo describe an incom-
plete spiral course, while Stein expresses a similar opinion with reference to the
several types that have fallen under his observation. The investigations of the
present author have elicited that a like disposition of the adoral cirri obtains in
various other species, which may therefore now be accepted as diagnostic of the
genus. This spire, furthermore, coincides with that of Halteria, it being its right
limb that is involute and descends into the oral fossa. Excepting for the absence of
the equatorial springing-setae, this genus might be compared with the one last named,
but in the length and shuttlecock-like disposition of the adoral cirri its members
still more nearly resemble those of Tintinnus, and with which they are more imme-
diately united through Strombidinopsis. The movements of the animalcules of the
genus Strombidium consist of a vigorous oscillating or rolling motion to and fro, as
though on a pendulum, interrupted, mostly when disturbed, by locomotion in a straight
line, combined with rapid rotation on their longitudinal axis. A similar oscillating
comportment has been already reported of Strombidinopsis and Calceolus, and recurs
again in Urocentrum and Gyrocoris. When exchanging their oscillatory or rotatory
motion for a rectilinear course, the likeness of these animalcules to detached roving
Vorticellcs is very noteworthy ; the earlier phases of Vorticella nebulifera, as elicited
by the recent investigations of Everts, as delineated at PI. XXXV. Fig. 39, are
furthermore scarcely distinguishable from the matured zooids of Strombidium turbo
or S. ClaparedL

Strombidium sulcatum, C. & L. PL. XXXII. FIG. 47.

Body subglobose, truncate, and longitudinally furrowed posteriorly ;
adoral cilia stout, equalling half the body in length ; contractile vesicle
spherical, subcentral ; colour brownish yellow. Length 1-400".

HAB.— Salt water : Bergen (C. & L.).

* ' Etudes sur les Microzoaires,' Paris, 1876.

634 ORDER PERITRICHA.

The discoverers of this species record that its motions in the water are remark-
ably swift and difficult to follow, as also that specimens occasionally in the midst of
their impetuous course suddenly fall to pieces, as though by magic, undergoing
diffluence with a rapidity observed of no other animalcule, though to some extent
approached in Arachnidium globosus. According to the recent investigations of
Biitschli,* the cuticular layer in this species is armed midway between the centre of
the body and the anterior margin with an even girdle of elongate, close-set
trichocysts. The figure accompanying the account of this variety seems, however,
to represent a distinct species, possessing a more elongate contour, and exhibiting
no trace of the posterior furrows that characterize Claparede and Lachmann's type.
It is here proposed to provisionally distinguish this last-named animalcule by the
title of Strombidium Butschlii.

Strombidium turbo, C. & L.

_ Body globose, slightly conical posteriorly, its surface smooth ; adoral
cirri equalling the body in length, very rigid. Length 1-700".
HAB. — Fresh water.

Strombidium Claparedi, S. K. PL. XXXII. FIG. 46.

Body smooth, transparent, elongate-pyriform, tapering posteriorly, about
twice as long as broad. Length 1—300".
HAB. — Pond water, among Conferva.

This, the largest recorded species of the genus, is easily recognized by its elongate
outline, and seems to be identical with a fresh-water species imperfectly observed by
Claparede and Lachmann,| but for which they have not proposed a distinct specific
title. Its movements agree with those recorded in the above generic description,
and correspond remarkably with those of Urocentrum turbo. On several occasions
this species has been observed by the author to attach itself to aquatic plants, or
other objects, by its posterior extremity, which appears to be of softer consistence
than the remainder of the body, and thus fixed draws currents of food-laden water
towards it by the vigorous vibratory action of its powerful adoral cilia, after the
manner of a Vorticella. Such a sedentary condition was only temporarily maintained,
the animalcule soon resuming its more active gyratoiy course.

Strombidium urceolare, Stein.

Body contracted centrally, anteriorly moderately, and posteriorly con-
siderably enlarged, almost pitcher-shaped ; peristome produced towards
the posterior extremity as an oblique furrow, bearing towards its anterior
extremity two or three closely set, large-sized vibratile cilia ; endoplast
small, oval ; contractile vesicle posteriorly situated. Dimensions unre-
corded. HAB. — Salt water : Baltic Sea.

Strombidium acuminatum, Stein.

Body attenuate, conical, acuminate anteriorly ; peristome produced
backwards nearly to the centre of the body ; the hinder half of the ventral
surface bearing an oblique supplementary row of fine vibratile cilia ;
colour yellow. Dimensions unrecorded.

HAB. — Salt water : Baltic Sea.

* ' Archiv fiir Mikroskopischer Anatomic,' Bd. ix., 1873. f ' Etudes sur les Infusoires,' p. 372.

GENUS MESODINIUM. 635

Strombidium viride, Stein.

Body obovate, obtusely conical anteriorly ; parenchyma coloured green
by the presence of innumerable enclosed chlorophyll-granules ; peristome
produced backwards as in Strombidium acuminatum, the ventral aspect
not having a supplementary row of fine cilia as in that species ; the cuticle
containing numerous minute staff-like bodies whose nature was not ascer-
tained, but which probably correspond with the trichocysts that form an
equatorial girdle in 5. Butschlii. Dimensions unrecorded.

HAB. — Fresh water.

Strombidium caudatum, From.

Body ovate, tapering posteriorly, and terminating in an elongate caudal
filament ; contractile vesicle posteriorly situated. Length, without filament,
i-iooo". HAB. — Fresh water.

But for the posterior location of the contractile vesicle, the author is disposed,
from the figure and brief description given by De Fromentel, to regard this type as a
Vorticdla detached, with its pedicle, from its fulcrum of support.

Strombidium globosum, From.

Body spherical, transparent ; ciliary wreath very small and inconspi-
cuous ; contractile vesicles large, two in number, posteriorly located.
Length 1-800". HAB. — Fresh water.

GENUS III. MESODINIUM, Stein.

Animalcules free-swimming, ovate or pyriform, the anterior extremity
prolonged in a snout-like manner, and perforated apically by the oral
aperture ; bearing between the snout-like prolongation and more inflated
posterior portion of the body a circular fringe of setose or cirrate locomotive
cilia. Inhabiting salt and fresh water.

The representatives of this genus appear to unite the characters of Halteria and
Didinium, they possessing the protrusible snout of the latter combined with a wreath
of locomotive cirri, which, while discharging the more ordinary natatory functions,
are also endowed with saltatory properties.

Mesodinium acarus, Stein. PL. XXXII. FIG. 40.

Body subturbinate, the posterior portion globose, the anterior one
conical, the two regions separated from one another by a raised annular
border, from out of which are produced the circle of locomotive cirri ; con-
tractile vesicle spherical, posteriorly located. Length of body 1-800".

HAB. — Pond and marsh water.

This species, as here figured, and obtained by the author from a number of
localities, is apparently identical with the type for which Stein first instituted the
generic title of Mesodinium. It may be readily distinguished from the two succeeding
salt-water forms by the raised border, bearing the locomotive cirri, which divides the
inflated posterior half from the conical anterior one. It has been frequently

636 ORDER PERITRICHA.

observed by the author that examples of this species can attach themselves to sur-
rounding objects by the distal end of their snout, which thus fulfils the purpose
of an adhesive sucker. The almost setose locomotive cirri, when such an attach-
ment is effected, quiver for a short interval with great rapidity, but finally become
entirely quiescent. The animalcules under these conditions, when seen from above,
may easily be mistaken for minute examples of the Radiolarian genus Actinophrys.

The adherent snout in this type is, as in Didinium, capable of protrusion for
the seizure of prey to a considerable distance. When swimming, its locomotion is
rotatory, varied by occasional leaps from side to side after the manner of an Halteria.
This leaping motion is apparently effected by a similar sudden flexure of the loco-
motive cirri, which, while not so long and slender as in the last-named type, are
of an almost setose character. On a recent occasion the author noted, in an
animalcule apparently belonging to this species, what appeared to be a circlet of
minute vibratory cilia at the base of the conical snout, in addition to the normal
setose series, but this observation has not since been confirmed.

Mesodinium pulex, C. & L. PL. XXXII. FIG. 44.

Body turbinate, globose posteriorly, conical and tapering as it
approaches the anterior projecting snout ; wreath of cirrose cilia developed
on an annular groove or constriction half-way between the centre of the
animalcule's body and the base of the snout-like process. Length
of body 1-1650". HAB. Saltwater.

This species, described by Claparede and Lachmann under the title of Halteria
pulex, is recognized by Stein as probably belonging to his genus Mesodinium. In
the diagnosis and description given by its discoverers it is represented as possessing
three long stylate processes, or bristle-like cirri, in advance of the mouth. Stein regards
these simply as three forward-projected locomotive cirri j but the present author is
inclined to accept them as an optical misinterpretation of the everted attenuate
proboscis, the two so-called outer styles representing the lateral walls, and the
central one the pharyngeal perforation of this structure. An almost identical
appearance is exhibited by Mesodinium acarus during the protrusion of this organ.

GENUS IV. ACARELLA, Cohn.

Animalcules free-swimming, more or less ovate, divided by an annular
constriction into a globose posterior and conical anterior portion, the
annular furrow bearing a wreath of long, slender, setose cilia ; the body
enclosed wholly or in part within an ovate or subglobular, transparent
sheath or lorica.

The type form of this genus, as described by Cohn,* closely resembles the
species first described by Stein under the title of Mesodinium acarus, and also the
Halteria (Mesodinium) pulex of Claparede and Lachmann, but is of very much
smaller size, and has the posterior portion of its body enclosed within a transparent
lorica.

Acarella siro, Cohn. PL. XXXII. FIG. 45.

Body elongate-ovate, the posterior portion the larger, rounded and
subglobular, the anterior one conical, apically truncate ; setose cilia of
the intervening annular constriction equalling in length the larger posterior

* " Neue Infusorien im Seeaquarium," 'Zeit. Wiss. Zool.,' Bd. xvi., 1866.

GENUS ARA CHNIDIUM. 63 7

portion ; lorica subglobular, reaching, when the animalcule is swimming
and extended, as far as the annular constriction. Length i-iooo".
Movements like those of Halteria, sometimes swimming smoothly and at
others springing from side to side. HAB. — Salt water.

GENUS V. ARACHNIDIUM, S. K.
(Greek, arachne, spider; eidos, like.)

Animalcules free-swimming, ovate or spherical ; oral aperture terminal,
central, surrounded by a circular wreath of large, flexible, tentaculiform
cilia, which constitute the only locomotive or prehensile organs ; endoplast
and contractile vesicle conspicuously developed. Inhabiting salt and fresh
water.

This new genus holds a position midway between Mesodinium and Sfrombidium,
it having the central mouth and even oral circle of cilia characteristic of the
former, but wanting, as with the latter, its special supplementary leaping setae.
This single oral wreath of cilia at the same time attains a much greater develop-
ment, and assumes a character completely distinct from either of the above-named
genera; these cilia, indeed, resemble rather small flexible tentacula than the
ordinary cilia or setae of the normal representatives of this group. In their more
ordinary condition these organs are recurved gracefully towards the posterior
extremity of the body, and when in active use exhibit a perfectly independent motion.
The spider-like aspect of the animalcules of this genus, with their rounded bodies
and straggling tentacle-like cilia, has suggested the title adopted for their distinction.
More correctly they may perhaps be likened to the free-swimming Ccelenterate genus
Arachnactis.

Arachnidium globosum, S. K. PL. XXXII. FIGS. 48 AND 49.

Body nearly spherical, smooth, transparent : oral cilia sixteen to twenty
in number, thick and tentaculiform, equalling the body in length ; endo-
plast very large, band-like, curved ; contractile vesicle spherical, subcentral.
Length 1-2000". HAB. — Pond water, among Conferva.

The normal mode of motion exhibited by this species is a rolling to and fro,
somewhat after the manner of Strombidium, but in a more sluggish manner.
Occasionally it darts backwards through the water with the tentacle-like cilia collected
in a bundle behind in the manner indicated at PI. XXXII. Fig. 49. Under these
last-named circumstances it presents a fanciful resemblance to a miniature Octopus
swimming backwards through the water in its accustomed manner. The endo-
plast attains a very large relative size, closely resembling in contour that of
many typical Vorticellidse. On one occasion the author observed an example
rapidly dissolve, as though by diffluence, in the water, leaving the thick band-
like endoplast as the only trace of its previous existence. This, no doubt,
subsequently breaks up, releasing the germs of a future progeny. The few
examples of this minute but beautiful animalcule so far encountered were obtained
by the author from a pond at Stoke Newington, in February 1874, in company
with Dinobryon sertularia, Salpingceca amphoridium, and other Flagellate types, then
the subject of special investigation. The drawings of the species, as here repro-
duced, were accomplished with the assistance of a magnifying power of 1200
diameters, obtained through the use of a J^-inch object-glass by Messrs. Powell
& Lealand.

638 ORDER PERITRICHA.

Arachnidium convolutum, S. K. PL. XXXII. FIG. 41.

Body egg-shaped, tapering slightly posteriorly, somewhat opaque,
spirally furrowed or convolute throughout its length ; oral cilia nearly as
long as the body, more numerous but not so thick as in A . globosus ;
endoplast band-like, curved ; contractile vesicle spherical, subcentral.
Length 1-750". HAB. — Salt water.

The form and proportions of this animalcule, in addition to its considerably larger
size and salt-water habitat, readily distinguish this type from the preceding one.
A single example only has up to the present time been met with, this having been
obtained by the author at Bognor, on the Sussex coast, in September of the
year 1872.

Arachnidium bipartitum, From. sp. PL. XXXII. FIGS. 42 AND 43.

Body subpyriform, with a subglobose inflated posterior, and a
smaller but also rounded anterior portion, the constriction dividing these
two regions from one another bearing the tentaculate locomotive cilia,
these long and slender, equalling the body in length, sometimes
used as ambulatory organs ; parenchyma transparent, enclosing numerous
spheroidal, refringent corpuscles. Length 1-800". HAB. — Fresh water.

This species is briefly described by De Fromentel * as a species of Halteria, but is
obviously more nearly related to the present genus. The faculty it possesses of walk-
ing over the surface of submerged objects with the aid of its locomotive cilia is as yet
not known to be possessed by any other members of the Halteriadae, but is possibly
shared by the preceding representatives of the genus Arachnidium. The locomotive
cilia in this type are more slender, and evidently of firmer consistence, than in the
two preceding species, and would seem to possess an almost stylate character. The
characteristic mode of progress through the water, as depicted by De Fromentel,
agrees essentially with that previously noted by the author of Arachnidium globosus,
all the locomotive cirri being gathered together and extended in front of the oral
aperture, while the animalcule swims backwards after the manner of an Octopus.
What, during such translation, constitutes the actual motile agency has not yet been
ascertained, but it would seem probable that additional fine locomotive cilia are
developed upon the oral region. Although not represented by De Fromentel in his
figures, he would seem to hint, in his brief description of the present species, that such
fine, scarcely perceptible cilia fringe the free margin of the anterior border.

GENUS VI. DIDINIUM, Stein.

Animalcules free-swimming, ovate or subcylindrical, provided with
an anterior and posterior ciliary wreath ; the anterior extremity snout-like,
enclosing a tubular, protrusible, prehensile proboscis, whose distal extremity
is perforated by the oral aperture ; anal aperture and contractile vesicle
posteriorly located ; multiplying by transverse fission, and by the sub-
division of the endoplast into germinal elements.

Neither of the ciliary wreaths in Didinium immediately surround the mouth or
take an important place in connection with that organ as in Halteria and Strombidium,

Etudes sur les Microzoaires,' 1876.

GENUS DIDINIUM. 639

but are subservient merely to the purpose of locomotion. It is perhaps desirable, in
recognition of this circumstance, that in conjunction with Mesodinium, it should be
separated as the representative of an independent family group.

Didinium nasutum, Mull. sp. PL. XXXII. FIGS. 50-57.

Body ovate or barrel-shaped, about twice as long as broad, rounded
posteriorly, the anterior border produced in a snout-like manner ; paren-
chyma coarsely granular, cuticular surface smooth ; the foremost ciliary
wreath developed close to the base of the snout-like anterior projection,
the hindermost girdle encircling the body at about a distance of one-third
of its total length from the posterior extremity ; proboscis slender, protru-
sible to a distance equalling the entire length of the body ; endoplast band-
like, curved ; contractile vesicle spherical, of large size, debouching upon the
anal aperture. Length 1-300". HAB. — Pond water.

The Vorticella nasuta of O. F. Miiller, which furnishes the type of both the genus
and species now under consideration, has recently been the subject of investigation
by Balbiani,* who has elicited details of high interest concerning both its structure and
life-history. By this authority it has been first recorded that the animalcule is able
to evert from its snout-like anterior extremity a proboscidiform organ of considerable
length, with which it seizes upon and sucks out the contents of other animalcules,
such as Paramczcium, in the same manner that an Acineta devours its living prey, or
transports it bodily, with the retraction of its proboscis, to its own interior.
Balbiani further ascribes to this form a tubular central digestive canal, presenting at
the pharyngeal or post-oral portion of its course a longitudinally striated aspect, which
is produced by the presence in its walls at this point of numerous rigid rod-like
filaments. These pharyngeal rods are, according to his observations, capable of
extrusion and are used by the animalcule for the purpose of paralyzing its prey.
From the account given of these elements, however, the author is inclined to
identify this rod-system as a whole with the pharyngeal rod-fascicles of Chilodon,
Prorodon, and other Hypotrichous and Holotrichous forms. A very regular proto-
plasmic circulation has been observed by Balbiani, flowing in a continuous stream,
immediately beneath the cuticle, towards the apical or oral pole, and returning along
the central axis formed by the digestive tract.

With Didinitim nasutum must be identified the so-called Chytridium Steinii,
figured and described by Dr. Ernst Eberhard in the ' Osterprogramm der Realschule
zu Coburg' for 1862, as also the more recent Wagnerella cylindroconica, described,
with an accompanying woodcut, by Wladimir Alenitzin, of St. Petersburg, in the
' Archiv f. Mikroskopische Anatomic,' Bd. x., 1874. Increase by transverse fission
is of very common occurrence in this type, such an approaching duplicative act
being always heralded by the accession to the body surface of two supplementary
ciliary girdles. In some instances spheroidal germ-like bodies were observed by
Balbiani occupying the place of the normal band- like endoplast, and through the
breaking up of which they were apparently produced. Subsequently these germs
were liberated as minute pyriform animalcules, bearing a single anterior circlet of
cilia, and corresponding closely with the adult state of the preceding genus Meso-
dinium. The growth of these germs into the perfect form has not as yet been
traced. The present author has on one occasion obtained this interesting animalcule
in the neighbourhood of Stoke Newington, London. A reference to the homo-
plastic resemblance that subsists between Didinium and the embryos of certain
metazoic organisms will be found at pages 576 and 577.

* " Sur le Didinium nasutum," ' Archives de Zoologie Experimentale,' 1873.

640 ORDER PERITRICHA.

Fam. V. GYROCORID-ffi, Stein.

Animalcules free-swimming, persistent in shape, but not encuirassed,
ovate or pyriform, provided with one or more spiral or circular wreaths
of cirrose cilia ; oral aperture lateral or ventral ; anal aperture postero-
terminal ; the posterior extremity frequently bearing a conspicuous stylate
or more or less flexuose caudal appendage.

The three genera included in this family group differ from all remaining
representatives of the Peritricha in the lateral location of the oral aperture.
Through Urocentrum a close relationship with the Heterotrichous genus Calceolus is
evidently established.

GENUS I. GYROCORIS, Stein.

Animalcules free-swimming, persistent in shape, separated into two
conspicuously distinct regions, the anterior one helmet-shaped or cam-
panulate, more or less rounded anteriorly, with a free mantle-like
posterior border, the hinder portion produced from the centre of this
border as a long claw-like style or tail ; a ciliated groove extending back-
wards from the anterior extremity along the ventral surface, then ascend-
ing obliquely and continued as a right-winding spire of long, powerful
locomotive cilia, which form a fringe round the free truncate margin of the
anterior or body portion ; oral aperture situated apparently near the centre
of the ventral ciliated groove ; anal aperture posteriorly located ; contractile
vesicle and endoplast conspicuous.

Gyrocoris oxyura, Stein. PL. XXXIII. FIGS. 1-6.

Body bell- or ' helmet-shaped, subpyriform ; claw-like tail or style
produced from the hinder margin, equalling the body in length ; cilia
forming the posterior marginal fringe very long and fine ; contractile
vesicle large, spherical, situated close to the base of the tail-like portion ;
endoplast represented by three or four, more rarely two, transversely
disposed ovate corpuscles ; a bluish, granular, crescent-shaped spot, corre-
sponding probably with the so-called eye-speck of other infusorial forms,
often present at the anterior extremity. Length, -including tail, 1-200".

HAB. — Stagnant water.

This form was first obtained by Stein in great profusion in stagnant water near
Prague, and is described by him * as exhibiting such rapidity of motion, through
revolution on its axis in a screw-like manner, that the greatest difficulty attends the
interpretation of its true form and character ; the oral aperture under these con-
ditions, while suspected to be situated in the ciliated ventral groove, was not
absolutely observed. The possible affinity of this form with the imperfectly described
Ccenomorpha medusula of Perty and the Trichodina tentaculata of Ehrenberg has been
recognized by Stein ; in both of these, however, the body portion appears to be more
nearly hemispherical or discoidal ; there is, again, no indication of a ventral ciliated
groove, and such cilia as are represented, though possibly erroneously, form a fringe
round the anterior border. An animalcule figured by Mr. Tatem in the ' Quarterly

* ' Sitzungsbericht der K. Bohmischen Ges. d. Wiss.,' S. 48, 1860.

GENUS UROCENTRUM. 641

Journal of Microscopical Science' for the year 1868, under the title of Ccenomorpha
convoluta, here reproduced at PI. XXXIII. Figs. 1-3, is evidently identical with
Stein's type. His brief account of the species, though it leaves much yet to be
recorded concerning this remarkable form, supplies some additional data of
importance. The body as described by this later observer, and as delineated at
Fig. i, is colourless, smooth, and conical, the anterior extremity curved somewhat
downward, and the posterior margin fringed at its edge with long, close-set cilia.
The tail-like portion is swollen at its base, somewhat eccentric, is as long or longer
than the body, and tapers to a point which is curved slightly upwards at its distal
extremity. In addition to its swift natatory mode of progression, Mr. Tatem relates
that from twelve to twenty of the cilia on the ventral surface present the character of
long stiff setae, and that with their aid the animalcule is enabled to creep over the
surface of algae or other submerged bodies ; the tail-like style is likewise described by
him as being sometimes bifid. The character and position of the oral aperture were
not determined, nor are any details recorded concerning the nature of the contractile
vesicle and endoplast. The former structure, although not recognized as such in
Mr. Tatem's description, is clearly indicated in his drawings in the same locality
first ascribed to it by Stein. Representations of a supposed earlier condition of this
organism are given by Mr. Tatem, one of which, Pi. XXXIII. Fig. 2, excepting
for the position of the ciliary wreath, corresponds remarkably with Perty's figures
of Coznomorpha medusula. This circumstance suggests the possibility that Perty
grounded his description of the last-named species upon young and certainly very
imperfectly observed examples of the present form. To complete the record of this
puzzling Peritrichous form, it is desirable to add that it is figured by Dr. Ernest
Eberhard in the ' Osterprogramm der Realschule zu Coburg ' for 1862, under the
title of Strotnbidium polymorphum, and there associated with Metopus sigmoides, which
is regarded by him as merely its earlier or larval condition. This presumed affinity
is referred to at greater length in the account given of the last-named species.

The diagnosis and more characteristic figures of Perty's Cocnomorpha medusula
are herewith reproduced, and should future investigation successfully establish the
identity of the two, this authority's generic and specific title will, in accordance
with the laws of priority, have to supplant that of Stein's. So far as can be at
present decided, the author is inclined to regard the species as distinct, hut the
genus identical.

Canomorpha medusula, Perty. PI. XXXIII. Figs. 26-28. — Body colourless,
transparent, bell-like or hemispherical, its surface sometimes plicate, the base concave
and truncate, with an irregularly notched border ; a tail-like process comparable to
the clapper of the bell depending from the centre of the body ; the margin of the
bell fringed with long cilia, which sometimes present the aspect of an undulating
membrane. Movements swift, rotating on its longitudinal axis. Length, with tail,
1-240" to 1-192". Hab. Standing water.

GENUS II. UROCENTRUM, Nitzsch.

Animalcules free-swimming, ovate or pyriform,- persistent in shape ;
body encircled by one or two circular girdles of cilia, and traversed on its
ventral surface by a longitudinal groove or furrow ; oral aperture ventral,
perforating the centre of the more posterior ciliary girdle ; an apparently
stylate, but more or less flexuose and adherent, caudal appendage pro-
duced from the posterior region of the body ; endoplast and contractile
vesicle conspicuously developed. Inhabiting salt and fresh water.

Urocentrum turbo, Mull. sp. PL. XXXIII. FIGS. 7-10.
Body unevenly pyriform, largest and inflated anteriorly, constricted
centrally, narrower and triquetrous posteriorly, the ventral surface somewhat
VOL. n. N

642 ORDER PERITRICHA.

flattened ; caudal appendage nearly equalling one-half the body in length,
flattened and flexible, distally adhesive ; ciliary girdles two in number, the
anterior wreath encircling the body at a short distance only from the frontal
border, the posterior one subcentral ; endoplast and contractile vesicle
posteriorly situated, the former band-like, curved, transversely placed, the
latter median, exhibiting at diastole a rosette-like contour ; parenchyma
transparent, colourless or pale yellow, enclosing anteriorly numerous
spheroidal globules. Length 1-500" to 1-280".
HAB. — Fresh water, among Lemna.

This animalcule was originally described by O. F. Miiller under the title of
Cercaria turbo, its present generic name being first employed by Nitzsch,* and after-
wards by Ehrenberg. By none of these earlier writers have the details of the ciliary
system been accurately interpreted, the small size and exceedingly active motions
of the species accounting mainly, no doubt, for this discrepancy. In no instance
as yet has this type been represented as possessing more than a single ciliary
girdle, this being further described as encircling the anterior border. The present
author has examined this same animalcule on repeated occasions, and has on each
of these determined with facility the presence under normal conditions of two such
girdles; the more anterior girdle, composed of slightly larger cilia, encircles the
periphery at a short distance only from the anterior extremity, leaving a small, bare,
cap-like border, while the more posterior circlet is continuous with the transverse line
of constriction that separates the wider and inflated anterior from the narrower and
more usually triangular hinder region of the body. At one period only of its
existence does the animalcule possess but a single girdle of cilia, this being imme-
diately after the process of transverse fission, in which case the old ciliary girdle in
each separated segment is retained as the posterior or oral one, and a new anterior
wreath subsequently developed between that and the anterior extremity. The
close resemblance in both general contour and comportment, that subsists between
Urocentum turbo and the Calceolus (Peridiniuni) cypripedium of Professor H. James-
Clark has been already referred to in the description given of that species. In
recognition of such likeness the author has recently examined examples of Uro-
centrum, obtained in the neighbourhood of St. Heliers, Jersey, with the special
object of ascertaining whether or not the few distinctive characters possessed
by Professor Clark's type were not also represented here. These features, as
previously explained, consist of the exceedingly fine ciliation of the entire surface
of the body behind the, in Calceolus, single anterior wreath of powerful cirrose cilia, and
the composite structure of the caudal appendage, which was found under high
magnification to consist of a bundle of agglomerated hair-like flexible setae in place
of a single stylate organ, as was at first premised. Specimens subjected to the most
rigid examination in both the living condition and as killed with osmic acid and
other reagents, betrayed no trace of cilia at any point separate from the two
characteristic annular wreaths, while the caudal appendage was equally proof
against resolution into a compound fasciculate structure, as reported by James-
Clark of Calceolus. This last-named organ was found, however, under increased
amplification, to exhibit certain structural peculiarities not previously observed. In
place of being rigid and stylate as at first supposed, it was now shown to be
flattened and band-like, to possess a considerable amount of flexibility, and to be
soft and adhesive at its more attenuate distal extremity. As with Calceolus,
the movements of this animalcule consist variously of free rotation in the
water to and fro upon its long axis as though mounted on a pendulum, while at
other times it darts to and fro in a straight line with great velocity, or it fixes
itself by the extremity of its caudal appendage to some solid object and spins

' Beitrage zur Infusorienkunde,' p. 4, 1817.

GENUS TELOTROCHIDIUM. 643

rapidly backward and forwards upon it as if on a pivot. It is under the last
named circumstances that the flexibility of this organ is manifest. When closely
observed it is then seen that with each rotation it is thrown into a twist of many
coils after the manner of a pliant band or cord, the next rotation relaxing this
flexure and coiling it in a similar manner in an opposite direction. The aspect of
the caudal appendage in its twisted state is so like that of a bundle of smaller
thread-like filaments or of a long drawn-out and sharply pointed screw, as observed
by Professor Clark of the homologous organ in Calceolus, that it is difficult to refrain
from a suspicion that in that type also it may eventually prove to possess a similar
band-like character. It is at the same time requisite to remark that in some
instances the caudal appendage of that organism appeared to him to be divided into
equal halves, representing possibly, however, an abnormal development, while at
other times it presented distally a brush-like aspect.

The contractile vesicle in Urocentrum is a very conspicuous object, exhibiting
at full diastole, as seen in profile, apparently two, but actually four, rounded lateral
sinuses whose diameter equals about one-half of that of the large spheroidal central
lacuna. With the act of systole the greater portion of the liquid contents is discharged
into the outer water, leaving, however, a small portion behind in each of the four
sinuses ; these now become distended, and coalescing with one another form the
characteristic spheroidal central vesicle, to which again lateral diverticula are added
and systole is repeated as before. The various aspects of the contractile vesicle
during these successive stages is shown at PI. XXXIII. Fig. 10, a to f, the
phenomena as a whole corresponding closely with what has been recorded by
Wrzesniowski of Enchelydon farctus and Trachelophyllum apiculatum. In August
1872, the author met with a salt-water representative of the genus Urocentrum
at Bognor, Sussex. From the sketches and brief notes made at the time, it would
appear to present little or no points of distinction from U. turbo ; the triangulation
of the posterior region of the body was perhaps more decidedly marked, while the
caudal appendage appears to have been more curved and claw-like. It is proposed
to provisionally distinguish this salt-water form of the species under the name of
Urocentrum turbo var. marinum. Under the action of dilute osmic acid the
animalcules of U. turbo speedily disintegrate, demonstrating the absence of an
indurated cuticle or cuirass, which under normal conditions might be suspected
to exist

GENUS III. TELOTROCHIDIUM, S. K.

(Telotrocha, worm-larva ; eidos, form.)

Animalcules entirely free-swimming, ovate or campanulate, possessing
no caudal appendage ; ciliary girdles two in number ; oral aperture opening
on the ventral surface, immediately behind the anterior wreath of cilia;
anal aperture postero-terminal ; contractile vesicle and endoplast con-
spicuously developed. Increasing by longitudinal fission. Inhabiting
fresh water.

Telotrochidium crateriforme, Mull. sp. PL. XXXIII. FIGS. 11-13.

Body campanulate or subquadrate, with an indented dorsal and
convex ventral or oral aspect ; ciliary wreaths developed at a short distance
only from the anterior and posterior extremities, the anterior one associated
with a thick annular border ; anal aperture postero-terminal, tubular,
permanently visible ; contractile vesicle single or jdouble, subcentral ; endo-
plast band-like, curved ; parenchyma transparent, pale brown or amber-

N 2

644 ORDER PERITRICHA.

coloured. Movements swift, rotating in alternate directions. Length
1-250". HAB. — Pond water.

Examples of this species were abundantly developed in a sample of water con-
taining Euglena acus and Distigma proteus remitted to the author by Mr. Thos. Bolton,
in November 1880. While at first sight presenting no inconsiderable resemblance
to detached Vorticellce, the recognition, on a more intimate acquaintance, of the pos-
terior location and conspicuous development of the anal aperture — from which the
passage of excreta was directly observed — together with the character of the oral
system, speedily indicated the necessity of assigning to this type a position altogether
independent of the Vorticellidse. Excepting, indeed, for the absence of an adherent
caudal appendage, it in many respects agrees with Urocentrum, and may be most
conveniently referred to that family group. The likeness suggested is manifested in
addition to the number and position of the ciliary girdles and ventral location of the
oral aperture, in the texture and pale brownish hue of the parenchyma, and in its mode
of locomotion. This, while accomplished in a forward direction, is accompanied by
the rotation of the animalcule in alternate directions, a slight displacement of the
generated force being alone required to convert it into that oscillating or pendulum-
like motion so highly characteristic of Urocentrum. While in most instances a single
subcentral contractile vesicle was alone to be detected, some few examples occurred
in which, as shown at PI. XXXIII. Fig. n, two such structures were distinctly
developed. It would seem, however, to be by no means improbable that such zooids
were about to multiply by the process of fission, which, contrary to that of Urocen-
trum, takes a longitudinal direction. It was remarked that the animalcules varied
very considerably among each other in their relative lengths and in the contour of
the posterior region. While more ordinarily the length nearly equalled twice the
breadth, the posterior extremity being in such case rounded or obtusely pointed,
examples were not unfrequently met with whose length did not surpass more than
one-half of the breadth, and the posterior extremity being abruptly truncate, the body
as a whole presented, as shown at PI. XXXIII. Fig. 12, a short discoidal contour.
Although the anterior ciliary wreath, with its thickened border, was in all instances
distinctly recognizable, the simple and smaller posterior girdle was not so clearly
perceived, and more often, indeed, presented the aspect only of a few lateral setose
appendages. At the end of a week's preservation in the living state all the
specimens received affixed themselves to the sides of the glass zoophyte trough to
which they had been transferred, and speedily entered upon the encysted state.
The band-like endoplast became subdivided into nodular fragments, but further
developmental phases were not observed. The remarkable homoplastic resem-
blance that subsists between the animalcules of this species and the so-called telo-
trochous larvae of certain Annelids, and which has suggested the generic title here
conferred upon it, is referred to, with an accompanying illustration, at pages 447
and 478 of the previous volume.

The identification of this type with the Vorticella crateriformis of O. F. Miiller,
figured and described by that authority close upon a century ago,* but which since
then up to the present time does not appear to have come within the notice of any
other investigator, has been quite recently and unexpectedly accomplished during a
final examination of the Miillerian species of Vorticella proper. The very clear
indication given in both Miiller's figures and accompanying text of the posteriorly
located anal aperture, added to all other details relating to contour, structure, colour,
and comportment in the water, has enabled the author to establish this identity in
the most conclusive manner, and to perpetuate a time-honoured specific title in place
of the new one which previously seemed unavoidable. In one of the figures given
by its original discoverer, /. c, pi. xxxix. fig. 7, an example of so-called conjugation
between two zooids is delineated, that must evidently be identified with the process
of longitudinal fission as observed by the author and figured in this treatise.

'• Animalcula Infusoria,' p. 278, and pi. xxxix. figs. 7-13, 1786.

GENUS TRICHODINA. 645

Fam. VI. URCEOLARIIDJE, Stein.

Animalcules free-swimming or adherent at will, discoidal, turbinate, or
hourglass-shaped ; the anterior border more or less circular, associated with
a spirally convolute ciliary wreath, the right limb of which is usually
involute, and descends into the oral aperture ; oral system closely
resembling that of the Vorticellidae, consisting usually of a widened
anterior entrance or vestibulum, and a somewhat prolonged pharyngeal
passage ; posterior border acetabuliform and adhesive, ciliate round its
peripheral margin, and mostly strengthened internally with a simple or
denticulate horny ring.

With the typical genera of this family, Trichodina and Urceolaria, are here included
two additional forms, Cydochceta and Licnophora, which exhibit in connection with
their oral systems a marked deviation from these normal types. In the first of
these, the anterior adoral ciliary wreath is entirely obliterated, or represented only by
that extremity which descends into the greatly prolonged pharyngeal passage. In
Licnophora it is the left-hand limb of the adoral wreath instead of the right, as in most
Peritricha, that is spirally convolute, a circumstance which, together with the oblique
setting and more elongate contour of the peristome-field, likens it, as pointed out by
Claparede, to the corresponding region in Stylonychia and other Hypotricha. The
adoral ciliary system in the two earlier established genera first named closely
resembles that of the ordinary Vorticellidae, but is more simplified through the non-
existence of a protrusible ciliary disc. To these last-named animalcules, in their
free-swimming state, having a supplementary circlet of locomotive cilia temporarily
developed at their posterior extremity, the Trichodin<z, indeed, exhibit a most remark-
able likeness. Such temporary free-swimming Vorticellidae, as here illustrated, more
especially in the case of Epistylis digitalis, see PI. XXXVIII. Fig. 16, are able in
a similar manner to adhere to, and creep over the surface of submerged objects
with the aid of their temporarily flattened posterior extremity and adventitious ciliary
circlet, which may without doubt be regarded as homologous with the ciliary wreath
that permanently fringes the acetabuliform posterior extremity of Trichodina and its
allies.

All the representatives of this family group are distinguished by their essentially
parasitic or commensal habits.

GENUS I. TRICHODINA, Ehrenberg.

Animalcules free-swimming, highly elastic and changeable in shape,
conical or discoidal ; oral aperture terminal, eccentric, continued into a
cleft-like pharynx, and associated with a horizontal, spirally convolute,
adoral wreath of cilia, the right limb of which is involute and descends into
the oral aperture ; anal orifice debouching into the vestibulum ; posterior
extremity discoidal, acetabuliform, its outer margin fringed by a circle of
long even cilia, its inner border strengthened by a more or less indurated
horny ring and supplementary denticles ; endoplast band-like or monili-
form ; contractile vesicle spherical, located near the termination of the
pharynx. Inhabiting salt and fresh water, usually infesting the cutictilar
surface of hydroid zoophytes and other Invertcbrata.

646 ORDER PERITRICHA.

Trichodina pediculus, Ehr.
PL. XXXI. FIGS. 48-52; PL. XXXIII. FIGS. 14-18; AND WOODCUT, p. 647.

Body conical, discoidal, or hourglass-shaped, according to the condition
of contraction or expansion, the elevation, when fully expanded, equal to,
but scarcely exceeding, the greatest diameter ; cilia of the posterior margin
exceeding in length those of the adoral wreath, inserted on the inner
side and at the base of a thin, transparent, annular membrane or velum,
into which the border of the posterior margin is produced ; horny ring
of acetabulum supplemented by a wreath of horny denticles consisting of
an external and internal series, each numbering about twenty-six, the
denticles of the outer series largest, short, thick and claw-like, those of
the inner set attenuate, sharply pointed, almost straight, and extending
to the centre of the interior discoidal area, composed in each instance of a
more solid radial portion and a membranous web-like lateral extension ;
endoplast band-like or moniliform, curved. Greatest height and diameter
of the extended body 1-360".

HAB. — Fresh water, infesting the cuticular surface of the fresh-water
polypes Hydra fusca and H. viridis ; sometimes on the branchial appen-
dages of the amphibian Triton cristatus,

This species, which may be regarded as the typical representative of its family
and genus, is often found in countless numbers on the surface of the body and
tentacles of the fresh-water polypes Hydra viridis and other allied species, to which
chosen hosts it either adheres firmly by its posterior acetabulum, or scrambles
rapidly over them with the aid of the girdle of cilia developed in the same region ;
leaving its adopted fulcrum of support, it is further capable of swimming through the
water with considerable velocity. Under these last conditions it may retain its fully
expanded form or contract itself into an almost wheel-like shape, and progresses
rotating on its axis, or, turning end over end, performs as it were a series of somer-
saults. The numerous forms this animalcule is able to assume by reason of the great
plasticity of the whole anterior portion of the body, has given rise to much diversity in
the accounts and figures of this species handed down to us by the earlier writers. By
far the most characteristic attitude presented is that subcylindrical or discoidal one,
with a slightly constricted centre and perfectly parallel anterior and posterior edges,
as shown at PL XXXI. Fig. 49, and in which condition, with its somewhat hollowed
extremities, it presents a contour that may be suitably compared with that of a dice-
box or with a fish's amphicoelous vertebra. Not unfrequently the area within the
anterior ciliary wreath or peristome is protruded in a conical form and in such a
manner that the entire body presents the hemispherical or turban-shape shown at
PI. XXXIII. Figs. 14 and 15. Stein was the first to show that in addition to the
apparently continuous circlet of corneous uncini which forms so conspicuous a feature
of the acetabuliform posterior extremity, there exists in the same region, and lying
without the last-named structure, a second finely striated, flexible, horny, annular
ring of a pale amber colour, and which, no doubt, adds materially to the efficacy of
the adhesive organ. This second corneous ring, though more transparent than
the circlet of uncini, was pronounced by Stein to be of much firmer consistence,
since it resisted the action of acetic acid after the latter had become dis-
integrated.

An exhaustive and masterly essay on the anatomy and physiology of Trichodina
pediculus, to which the author is indebted for many points embodied in the foregoing
diagnosis, was contributed by Professor H. James-Clark to the ' Memoirs ' of the

GENUS TRICHODINA.

647

Boston Society of Natural History, vol. i., 1865, and is reprinted in 'Annals of
Natural History' for June 1866. Several of the more important structural features
elicited through this investigator are reproduced in the accompanying woodcut.
According to this authority the elongate dicebox-like contour referred to and
reproduced in the figure first cited, represents the normal one maintained by this
animalcule in a state of health, the turban-shaped or conical ones given by
Stein and other writers being assumed only when in a sickly condition, or when
confined within too small a space for perfect freedom of motion. The periphery
of the body behind the adoral ciliated disc is described by Professor Clark as exhibit-
ing in transverse optical section an exceedingly irregular outline, arising from the
fact that the body is fluted and ribbed exteriorly from one end to the other by irregular

f. y

Trichodina pediculus, Ehr.— i. Diagrammatic illustration of longitudinal optical section. 2. A basal view of the
adherent apparatus, velum, and part of the posterior row of cilia, X 950. 3. Two of the uncini with their corresponding
radii from the adherent apparatus of a dead specimen X 2000. The lettering is alike throughout : a, anal aperture ;
6, vibratory crown ; c, bottom of the cupuliform disc ; dt peristome opposite and beneath the vestibular aperture ;
d\, peristome, dorsal region ; d 2, peristome, ventral region ; e, lumen of the edge of the row of vibrating cilia, hitherto
supposed to be a distinct vestibular seta ; f, profile of the velum ; fi, free edge of the velum ; _/2, the basal edge or
line of attachment of the velum ; g, basal wreath of cilia ; h, hooks or uncini of the adherent organ ; h 2, the spur, and
h 3, the horizontal limb of the uncinus ; i, the radii ; i i, the " nail-shaped piece " ; it, its head ; 13, the membranous
web ; k, the membranous crest of the uncini ; /, the profile of the " striated membrane " ; / i, its distal edge ; 1 2, the
coarser striae as seen on its front face ; 1 3, its proximal edge ; 1 4, 1 5, a portion of the posterior face of the striated
membrane showing the finer striae ; nt, entrance to the vestibule ; », nucleus or endoplast ; o, cesophagus ; /, the outer,
and / i, the inner walls of the body ; s, general digestive cavity ; v, vestibule. (After Prof. H. James-Clark.)

longitudinal furrows and projections. At first it was presumed that these rib-like
structures were of a muscular nature, but they were ultimately determined to be
merely folds and thickenings of the body-wall. The production of the truncate
posterior margin of the body as a thin transparent membrane, into the base of
which, and on its inner side, the cilia of the posterior fringe are inserted, as estab-
lished by Professor Clark, reconciles in a most satisfactory manner the somewhat
conflicting accounts of this region given by other observers. By the majority of
these the posterior margin is represented as simply fringed with cilia, while by others,
including more especially Siebold, it has been reported as consisting solely of a thin,
non-ciliate, undulating membrane. Upon the accessory membrane now demonstrated
to exist in combination with a fringe of cilia, Professor Clark has proposed to
confer the appropriate title of the " velum." The endoplast in the examples
examined in the beginning of October by this same authority was found to form a
thick, knotted, or moniliform band, extending over three-quarters of a circle in close
vicinity to the truncated base. An apparent instance of the genetic union of a
larger and smaller zooid of the species after the manner of the Vorticellidae, and in the
accomplishment of which process the smaller unit presents the aspect of a mere bud-
like excrescence attached to the periphery of the larger one, has been reported by

648 ORDER PERITRICHA.

Busch,* his figure of the same, as here reproduced, PI. XXXI. FIG. 52, being at
that time interpreted as an example of gemmation. An approximate estimate of the
exceedingly diverse contours that may be presented by Trichodina pediculus under
varying conditions may be gained through a reference to the numerous figures of the
species given in the accompanying illustrations, and among which will also be found
a representation of its characteristic aspect as crowded socially upon the portion of a
tentacle of Hydra vulgaris. A somewhat remarkable isomorphic likeness is found to
subsist between the representatives of the genus Trichodina, as typified by the present
species, and the free-swimming embryos, or so-called " trochospheres" of certain
Polyzoa; a representation of one such larva, reproduced from a drawing placed
at the author's disposal by Mr. H. E. Forrest, is delineated for the purpose of com-
parison at PI. XXXI. Fig. 53.

Examples of Trichodina pediculus have been recently obtained by the author from
a new habitat, namely, in company with Spirochona tintinnabulum on the branchial
appendages of larvae of Triton cristatus remitted him from the neighbourhood of
Dundee by Mr. John Hood in December 1880. Through a careful investigation of
the horny armature of the acetabulum, the author has been able to entirely confirm
Professor Clark's structural interpretation of this element embodied in Fig. i of the
accompanying woodcut, on all points save one, which relates to the development of
the membranous expansions or webs of the internal teeth or radii. According to
Professor Clark, see Woodcut, Fig. 3 /, these webs are produced on the inner and
larger of the two angles formed by the juncture of the shaft or transverse piece,
while in those examined by the author, obtained from the triton, such structure, as
represented in PI. XXXIII. Fig. 18, is developed on the external or smaller of these
angles. This composition of the structure which appears at first sight, or without
the aid of a very high magnifying power, to be a simple continuous denticulate ring
out of a number of separate elements, as first demonstrated by the American
authority and confirmed by the author's observation, accounts for its rapid dis-
integration under treatment with acetic acid, previously recorded. As observed by
Professor Clark, the more delicate striations of the posterior face of the second
simple ring afford a suitable test object for the resolving qualities of a one-eighth
inch objective. The structure, indeed, in its isolated form, bears no inconsiderable
resemblance to the discoidal frustules of certain diatoms. Taken in its entirety, the
complex adhesive apparatus of Trichodina, with its horny ring and denticles, would
seem to find its nearest parallel in the adherent organs or acetabula of the Cephalo-
poda, which are likewise commonly strengthened by a correspondingly striated,
and for the most part denticulate, horny annulus. The structure as reproduced, or
more correctly pretypified, in this minute animalcule is, however, the more remark-
able as being the product of a unicellular organism. The Hydra infested with
Trichodina pediculus often entertain as a second infusorial guest numbers of the
Hypotrichous form Kerona polyporum. Where the two abound it may be not un-
frequently observed that the Trichodina mount upon the backs of their companions,
and thus utilize them, as a man might a horse, for the enjoyment of locomotion
without having to participate in the labour of its production. It is of interest to
record that so late as the year 1850^ Professor Louis Agassiz made the attempt to
demonstrate that the parasitic Trichodina, represented the medusoid form of the
associated Hydra, while still later J the same authority proposed to identify the
ordinary Vorticelliclse as an aberrant group of the Polyzoa.

Trichodina Steinii, C. & L. PL. XXXI. FIG. 45.

This species agrees in all respects with T. pediculus, with the excep-
tion of the structure of the posterior horny ring, which, according to
Claparede and Lachmann, and as represented on the accompanying illus-

* ' Muller's Archiv,' 1854. f ' Proceedings Boston Society of Natural History,' p. 354.

J ' Essay on Classification,' 1857.

GENUS URCEOLARIA. 649

trations, appears under moderate amplification to be continuous and
denticulate only on its outer edge ; the number of denticulations as figured
by these authorities corresponds with that of the form last described.
HAB. — Fresh water, on a species of Planarian.

Trichodina digitodiscus, Stein.

Animalcules similar in aspect to T. pediculus, but of smaller size, the
posterior adhesive disc, as seen under moderate magnification, apparently
containing two horny rings, the outer and more slender one being finely
denticulate on the outer margin only, and the smaller but thicker inner
one having from twelve to fourteen stout uncini on the outside, and also
numerous very fine, short, bristle-like denticulations on the interior margin.

HAB. — Fresh water, on the brown polype Hydra vulgaris, more than
on H. viridis.

Trichodina baltica, Quenn. PL. XXXIII. FIGS. 19-21.

Body turban-shaped, the height when elevated nearly equalling the
diameter ; horny ring of the suctorial disc toothed on both its outer and
inner border, the outer teeth slender, uncinate, and recurved outwards, the
inner ones smaller, straight, and aculeate. Diameter of body 1-5/5" to
1-400". HAB. — Salt water, on Neritinafliiviatilis.

Apart from its marine habitat, this species may be distinguished from T. pedi-
culus by the character of the denticles of the chitinous ring that lines the posterior
acetabulum. These are of a considerably more slender character, and are united
with each other, as shown in the accompanying figure, reproduced from Quennerstedt,*
on an apparently entirely distinct system.

Trichodina scorpsena, Robin. PL. XXXI. FIGS. 46 AND 47.

Body turban-shaped, the superior surface convex, dome-like, the inferior
one concave ; cilia of circular peristomal wreath larger than those of the
posterior border; horny armature of acetabulum apparently resembling
that of Trichodina pediculus. Diameter of body 1-600".

HAB. — Salt water, on the branchia of fish belonging to the genera
Scorpcena and Trigla.

This species is figured and briefly described by Professor Ch. Robin in the
'Journal de 1'Anatomie et Physiologic,' torn, xv., 1879. See also 'Journal of the
Royal Microscopical Society,' London, October 1 880.

GENUS II. URCEOLARIA, Stein.

Animalcules similar to those of Trichodina, but the adherent sucking-
disc or acetabulum provided with a simply striated, non-denticulate
corneous ring ; the anterior region usually more attenuate, and with the
peristome obliquely set.

* ' Sveriges Infusoriefauna,' Heft iii., 1869.

650 ORDER PERITRICHA.

Urceolaria mitra, Stein. PL. XXXI. FIG. 44 AND PL. XXXIII. FIG. 22.

Body cylindrical or conical, its height when extended equal to about
twice its breadth, inclined at a considerable angle from its base of attach-
ment ; the anterior ciliary wreath somewhat obliquely set, capable of
being completely withdrawn within the substance of the body, the peri-
stome then contracting over it ; pharyngeal cleft conspicuous, produced
through about one-half of the extent of the body ; the contractile vesicle
stationed near the centre of this cleft ; endoplast posteriorly situated,
linear, curved. Length of extended body 1-1600".

HAB. — Fresh water, on Planaria torva.

As originally pointed out by Claparede and Lachmann, the figure and description
of this species given by Stein,* reproduced at PI. XXXIII. Fig. 22, in which cilia are
represented as forming a marginal band on each side of the anterior portion and dis-
posed at right angles to those of the posterior wreath, is a misinterpretation, the
anterior ciliary system agreeing essentially with that of Trichodina pediculus, except-
ing that the disc as a whole is somewhat obliquely tilted. Stein, in his more
subsequent writings, has fully recognized the accuracy of this emendation of the
diagnosis of the species on the part of the Swiss authorities.

GENUS III. CYCLOCH^ETA, Jackson.

Animalcules free-swimming, discoidal or turban-shaped, the ventral
surface forming a circular adherent sucker, as in Trichodina, its margin
bordered with a fringe of locomotive cilia, and strengthened interiorly by
a toothed horny ring ; oral aperture situated laterally in the angle formed
by the junction of the body with the adherent disc, not associated with
a buccal ciliary spire, but continued deeply into the substance of the body
as a finely ciliated pharynx ; a row of long, erect, bristle-like appendages
forming a circle round the body immediately behind the border of the
acetabulum.

The distinction of the type form of this genus from Trichodina and Urceolaria
consists in the absence of the anterior adoral groove and spire of cilia, which
would appear to be entirely obliterated, but is perhaps to a certain extent replaced
by the more posterior circlet of long, erect setae. On the other hand, however, as
suggested by its discoverer, these abnormally developed setae would seem to coincide
to some extent with the characteristic equatorial girdle of setose springing-hairs
of the genus Halteria.

Cycloehaeta spongillse, Jackson. PL. XXXIII. FIGS. 23 AND 24.

Body elastic and changeable in form, usually depressed, turban-shaped,
about twice as broad as high ; pharynx produced inwards to the centre of the
body, its interior wall finely ciliate ; the horny ring within the adherent disc
apparently forming one continuous piece having thirty-seven short external
booklets, and an equal number of long, slender, inwardly projecting radii ;
posterior setae sixteen in number, forming an erect fringe whose altitude
equals about twice that of the body ; contractile vesicle situated a little

* 'Die Infusionsthiere,' 1854.

GENUS LICNOPHORA . 651

above the termination of the ciliated pharynx ; endoplast elliptical, located
a little to one side of the same. Diameter of body 1-416".

HAB. — River water, infesting the interstices of the fresh-water sponge
Spongillafiiiviatilis.

This species, described by Mr. N. H. J. Jackson in the ' Quarterly Journal of
Microscopical Science' for July 1875, was found by him infesting the outer or
cortical layer of examples of the fresh-water sponge Spongilla fluviatilis, taken from
the river Cherwell at Oxford, and were obtained by tearing up small fragments of this
organism under the microscope. Its motions from one portion of the sponge to the
other were observed to be very rapid, like those of Trichodina pediculus, it in the same
manner swimming with the adherent disc projecting forwards. The characteristic
external circlet of long spine-like setae are recognizable only when the animalcule is
at rest. The locomotive cilia fringing the periphery of the adherent disc were found,
under high magnification, to have a small bulbous enlargement at their point of
junction with the periphery. The presumed endoplast, with one exception invariably
present, took the form of an ovate, greenish, granular body, situated a little above the
centre of the ciliated pharynx.

GENUS IV. LICNOPHORA, Claparede.

Animalcules free-swimming or temporarily attached to a selected host,
highly elastic and changeable in shape, somewhat hourglass-shaped, having
an expanded, suctorial, posterior extremity or foot, a slender, flexible, more
or less compressed, stalk-like central region, and a dilated anterior body-
portion or capitulum ; the dilated capitulum obliquely flattened or concave
anteriorly, bearing a peristomal or adoral ciliary wreath, the left limb of which
is involute and descends into the oral fossa, the latter not followed by a
conspicuous ciliated pharynx ; the adherent posterior extremity enclosing
a delicate membranous ring, and bearing a single peripheral fringe of cilia.

This genus has been instituted by Claparede* for the type originally described
by Cohn under the name of Trichodina Auerbachii, to which a second species has
been added by the first-named writer. Although at first sight the character of the
adhesive posterior extremity and the habits of the animalcule closely correspond with
those of the genus Trichodina and its allies, the structure of the peristomal region is
so distinct that Claparede regards it merely as a " mimetic " form of the latter,
requiring an independent family position. No details of the developmental pheno-
mena of either of the two known species have been as yet recorded, nor has the
presence of an endoplast or contractile vesicle been determined. The food-sub-
stances received at the oral aperture do not pass beyond the posterior border of the
capitulum. The parenchyma in both instances is exceedingly soft, rapidly breaking
up by diffluence when experimented on with reagents, or if subjected to abnormal
tension.

Licnophora Auerbachii, Cohn sp. PL. XXXIII. FIG. 30.

Body irregularly hourglass- or dumb-bell-shaped, the posterior adhesive
part having a raised rim or border, the pedicle-like central portion thickened
and compressed, the anterior capitulum ovate or pyriform, with an elongate,
somewhat harp-shaped fringe of large adoral cilia. Length 1-500" to 1-400".

HAB. — Salt water, occurring plentifully on the cuticular surface of the
Planarian Thysanozoon tuberculata: Naples (Claparede).

* ' Annales des Sciences Naturelles,' torn, viii., 1867.

652 ORDER PERITRICHA .

This species, as originally described by Cohn,* was met with in considerable
abundance on and among the dorsal papillae of a small deep-water Nudibranch,
apparently Doris muricata. A species of Trichodina referred to but not described
by Moebius and Meyer in their ' Fauna of Kiel,' as occurring on another Nudibranch,
JEolis alba, is probably also identical with this type.

Licnophora Cohnii, Clap. PL. XXXIII. FIG. 25.

Body proper or capitulum more orbicular than in the preceding species,
joined to the suctorial foot by a slightly compressed and usually more
attenuate pedicle ; peristomal ciliary wreath of relatively larger size than in
L. Auerbachii, describing an almost circular spire, its cilia very long and
slender^ Length 1-500" to 1-400".

HAB. — Salt water, on the branchiae of the Annelid Psyrmobranchus
protensus.

Fam. VII. OPHRYOSCOLECID^E, Stein.

Animalcules free-swimming, ovate or elongate, soft or encuirassed, pos-
sessing a peristome and protrusible ciliary disc as in the Vorticellidae ; one
or more style-like caudal appendages usually developed at the posterior
extremity ; anal aperture postero-terminal or opening into the vestibulum
or oral fossa.

As originated by Stein, this family group includes only the two endoparasitic
genera Ophryoscolex and Entodinium, animalcules which have up to the present time
been examined by no other special student of the Infusoria, and are but briefly
described by him, without illustration, in the year 1858.! There can be but little
doubt, however, that Stein's types include the infusorial forms reported by MM. Gruby
and Delafond,| as inhabiting in prodigious numbers the first and second stomachs
— rumen and reticulum — of various ruminants, the majority of these animalcules
being encuirassed and comparable in aspect to Rotifera. One species, more espe-
cially, represented by them as having a long, flattened body and projecting tail,
with a convex dorsal and plane ventral surface, indented posteriorly, and a girdle
of cilia round the centre of the body, length i-ioo", is apparently identical with
Stein's Ophryoscolex Purkynjei, while another, described as closely resembling the
Rotifer Brachionus polyacanthus of Ehrenberg, is probably the Entodinium dentatum
of the same writer. The numbers of these animalcules found by the French savants
infesting the indicated viscera of the sheep are something astounding. In five
centigrammes of alimentary matter taken from the two first stomachs of this rumi-
nant it was ascertained that no less than one-fifth of this total weight was composed
of the bodies of these organisms. In the third and fourth stomach — psalterium and
abomasum — of the same animal only dead or empty carapaces were to be found, the
softer and nutrient parenchyma having apparently been digested. From these
facts MM. Gruby and Delafond argue that the food-supply of ruminants, though
ostensibly of a purely vegetable nature, consists to a very considerable extent of
microscopic animal organisms, which develop freely and with great rapidity in the
first and second stomachs of their associated host, but are killed and assimilated on
passing into the third and fourth. Like results were obtained by them on examining
the viscera of a horse, for while found living in vast numbers in the cascum and
dilated colon, dead and empty carapaces were alone encountered in connection
with the contracted colon and rectum. It was found possible to preserve these

* " Neue Infusorien im Seeaquarium," 'Zeit. Wiss. Zool.,' Bd. xvi., 1866.
t ' Abhandlungen d. Konigl. Bohmischen Gesellschaft d. Wiss.,' Bd. x. p. 69.
j 'Comptes Rendus,' Dec. 1843.

GENUS OPHRYOSCOLEX— ENTODINIUM. 653

animalcules in health for a considerable interval — nine hours or more — by placing
them in glass tubes containing the stomachal fluids of their host, maintained at a
temperature of from 30° to 35° centigrade.

The present author provisionally refers to this family group the Astylozoon
fallax of T. W. Engelmann, which, while included by Stein among the ordinary
Vorticellidae, appears to exhibit in its free-swimming condition, and possession of
stylate caudal appendages, a closer relationship to the two genera above named.
The trend of the adoral wreath and the assumed position of the anal aperture may
perhaps be deemed of sufficient import for their isolation, but as in either case
the animalcules have been examined by no means exhaustively, and by but one
observer, their provisional alliance appears desirable.

GENUS I. OPHRYOSCOLEX, Stein.

Animalcules free-swimming, ovate or elongate, cuticular surface densely
indurated or encuirassed ; oral aperture anteriorly situated, associated with
an extensile and retractile peristome ; ciliary wreath like that of Vorticella,
except that the left limb, instead of the right, descends into the oral fossa ;
the centre of the body half encircled dorsally by an arcuate row of stout
uncinate cilia or setae ; a long, stylate, tail-like appendage produced back-
wards from the post-ventral surface, the anal aperture situated close to
the base of this style ; endoplast conspicuous ; contractile vesicles usually
multiple. HAB. — Endoparasitic.

Ophryoscolex Purkynjei, Stein.

Body elongate, somewhat vermicular, rounded posteriorly, bearing in
addition to the tail-like style three short, curved, claw-like spines ; the
anterior margin truncate, closing in a sphincter-like manner over the peri-
stome when retracted ; the ventral surface flattened, the dorsal and lateral
ones convex ; endoplast elongate-ovate, having a round attached endo-
plastule, situated on the right side of the body ; contractile vesicles two or
three in number, spherical. Dimensions unrecorded.

HAB. — Endoparasitic, within the first and second stomachs of sheep and
cattle.

Ophryoscolex inermis, Stein.

This species corresponds with O. Purkynjei, but is devoid of the short,
claw-like spines at the posterior extremity ; increase by transverse fission
has been observed in this, but not in the last-named type.

HAB. — Identical with that of O. Purkynjei.

GENUS II. ENTODINIUM, Stein.

Animalcules free-swimming, ovate, more or less flattened ; cuticular
surface smooth and densely indurated ; oral aperture and peristome as in
Ophryoscolex ; anal aperture postero-terminal ; no central girdle of setose
cilia, often with one or more terminal spines ; endoplast band-like, having

654 ORDER PERITRICHA.

an attached endoplastule ; contractile vesicles usually two in number, the
one anteriorly and the other posteriorly located.

HAB. — Endoparasitic within the first and second stomachs of various
ruminant Mammalia.

This genus differs from Ophryoscolex in the absence of the central girdle of
uncinate or setose cilia. Three species are very briefly distinguished by Stein, and in
no case has a representation of any one of these been published.

Entodinium bursaria, Stein. — Body long, rounded posteriorly, having a depression
in this region, in which the anal aperture is situated ; no caudal spines.

Entodinium dentatum, Stein. — Posterior border armed with six inwardly curved
claw-like spines.

Entodinium caudatum, Stein. — Inflated dorsally, excavate or emarginate poste-
riorly ; the one side bearing a long tail-like spine, and the opposite one two tooth-
like points.

GENUS III. ASTYLOZOON, Engelmann.

Animalcules free-swimming, soft and contractile, more or less campanu-
late or pyriform, attenuate posteriorly, and terminating at that region in one
or two tail-like, setose appendages ; peristome, ciliary disc, and vestibular
cleft as in Vorticella ; anal aperture opening into the vestibulum ; cuticular
surface naked, smooth or delicately striate.

Astylozoon fallax, Eng. PL. XXXIII. FIG. 29.

Body irregularly pyriform, tapering posteriorly, and there terminating
in two caudal setae equal in length to about one-quarter of that of the entire
body ; the dorsal border evenly convex, the ventral one gibbous ; peristome
slightly dilated, sloping obliquely towards the dorsal aspect ; ciliary disc
not elevated much above the margin of the peristome ; vestibular cleft
produced obliquely backwards towards the ventral border ; cuticular surface
finely striate transversely ; contractile vesicle situated close beneath the
peristome ; endoplast kidney-shaped, subcentral. Length 1-250".

HAB. — Fresh water.

This interesting species was described by T. W. Engelmann in the year 1861,*
being obtained by him from river water that had been kept isolated for three
months, and which yielded under examination no other species of animalcule.
Deprived of the characteristic caudal spines, its likeness to a detached zooid of
Vorticella, or Epistylis was very manifest. Spheroidal encystments were observed on
several occasions.

Fam. VIII. VORTICELLID-ffi, Ehr.

Animalcules mostly highly contractile, ovate, subcylindrical or campanu-
late ; sedentary or temporarily free-swimming, stalked or sessile ; solitary or
united in social, dendriform, or mucus-immersed colonies ; naked, or secret-
ing indurated sheaths or loricse ; oral aperture terminal, eccentric, associated
with an adoral ciliary spire of one or more convolutions, the right limb of
which usually descends into the oral entrance or vestibulum, the left one

* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. 4.

FAMILY VORTICELLID&. 655

being more or less convolute around an elevated and protrusible central area
which constitutes the so-called ciliary disc ; vestibulum continued backwards
upon the substance of the body as a conspicuous or cleft-like pharynx, and
often further prolonged as a narrow, more or less distinct, tubular oesophagus ;
a long, solitary, setose appendage, the vestibular seta or "sole deLachmann"
often attached to the upper wall and projecting a considerable distance
beyond the entrance of the vestibulum, the entire anterior extremity of the
body, including the protrusible ciliary disc and oral entrance, encircled by a
usually conspicuously raised border or peristome, this border or peristome
closing sphincter-wise over the ciliary disc and oral entrance when the
former is retracted ; anal aperture opening into the vestibulum ; contractile
vesicle single, spherical, located close to the anal aperture, and debouching
upon the vestibulum ; endoplast mostly band-like ; increasing usually by
longitudinal, rarely by transverse fission, the liberated zooid in these
instances usually developing prior to, and retaining during its short free-
swimming existence, a posterior circlet of powerful locomotive cilia, which
are again absorbed on a suitable site for attachment being secured ; the
survival or rejuvenation of the species further provided for through the conju-
gation or genetic union of two dissimilar zooids, the one (male ?) minute and
migrant, and the other (female ?) normal and sedentary, and by develop-
ment out of the endoplast of minute, free-swimming germs. Inhabiting
salt and fresh water ; rarely, if ever, possessing trichocysts.

The family of the Vorticellidae represents one of the largest and at the same time
the most natural and typical group of the Peritrichous order. All its members are
at once recognized by their normal sedentary condition and by the characteristic
structure of the oral system detailed at length in the foregoing diagnosis and in
that of the more essentially representative genus Vorticella. In but few of the
numerous genera included in this family is there any marked divergence from this
formula, that which exists being manifested by a greater development of some one
element at the expense of another constituent part of this last-named system.
Thus, in the genus Spirochona, the external edge of the prominent encircling border
or peristome is mostly suppressed, while its inner one is abnormally developed as a
transparent and highly elevated spiral membrane. On a less conspicuous scale a
similar deviation of the peristome-border from its more normal form obtains in the
genera Pyxidium, Opereularia, and Lagenophrys ; the ciliary disc, however, exhibits
an additional modification in these three instances, being isolated, laterally attached,
and presenting in its extended condition the aspect of a stalked operculum. By
Ehrenberg, Siebold, Perty, and other early writers the family of the Vorticellidae as
here constituted is separated into two or even three groups of equivalent value;
Vaginicola and its loricate allies being comprised under the family title of either the
Ophrydina or Vaginifera, the first of these two titles being reserved by Perty for the
reception only of Ophrydium, By Stein even,* a similar separation of the naked
from the loricate or mucus-immersed forms is maintained, though that the two are
too intimately related for such a broad separation is amply exemplified by the
following examples. Thus in certain species of Opereularia, such as O. nutans and
O. berberina, the cuticular surface is considerably indurated, and remains, like the
empty sheath of a Cothurnia, after the decay of the enclosed parenchyma ; while in
Lagenophrys the adnate lorica is scarcely distinguishable from an indurated cuticle.
Through Gerda fixa, and the newly described Ophionella picta, on the other hand,

* ' Organismus,' Abth. ii., 1867.

ujfLIBRARY

656 ORDER PERITRICHA.

the apparent gulf between Ophrydium and the more ordinary naked or loricate
Vorticellidae is effectually bridged. This last-named genus may, in fact, in accord-
ance with the results of Wrzesniowski's and the author's investigations, be regarded
as a slime-immersed Epistylis, all the zooids comprising a colony-stock being in a
like manner united by a slender branching unretractile pedicle. The elegant tree
or shrub-like colonies and variously modified loricae formed by many of the genera
of this family have hitherto won for them an amount of interest and popularity
possessed perhaps by no other members of the Ciliate group, but, as already shown
in the preceding volume, these have now to contend for the palm of beauty with
formidable rivals among the humble Flagellata, and wherein, on a comparatively Lilli-
putian scale, we find mimetically foreshadowed as many or even more variations of
tree or vase-like growths than are embodied in the present more familiar and highly
attractive group. As a necessary accompaniment of the combined sedentary and
eminently social habits of the majority of the representatives of this family, many of
them build up associated colony-stocks of so considerable a size as to form in their
natural habitats an appreciable and even conspicuous feature to the unassisted
vision. Hence also it is that the Vorticellidae are found to comprise the earliest
known of infusorial types, certain of them having been discovered by Leeuwenhoek
over two centuries ago, while the typical genus Vorticella lays claim to the illustrious
Linnaeus as its founder.

A moot point concerning the structural features of the Vorticellidae is connected
with the apparently long bristle-like appendage frequently seen projecting to a
greater or less extent from the vestibular fossa of the various members of this group,
to which attention was first directed by Lachmann. This debatable structure, as
recognized by various recent investigators, has been usually distinguished by
the title of the " sole de Lachmann" first given to it by M. Claparede, but is here
more often referred to as the " vestibular seta." A few authorities, on the other
hand, and more especially Professor H. James-Clark,* have called in question the
existence of such ah appendage, and consider it to be merely the optical image
produced by the descending adoral fringe of cilia as seen in profile, or as he puts it,
by the intersection of two such rows. In certain instances again — see Opercularia
stenostoma — there can be but little doubt that this so-called organ is rightly the
optical outline of a delicate hyaline membrane. In many species of Vorticella and
Epistylis, nevertheless, the author is quite satisfied that such a structure exists, quite
independent of the adoral cilia, and such a decision is fully supported by the
recent investigations of Greeff and Wrzesniowski. The more intimate structure of
the pedicle in Vorticella, the typical representative of the family group, is treated of
in the account given of that genus, but a few of its more important modifications in
other allied genera may be here enumerated. In Carchesium and Zoothamnium it
consists similarly of a contractile central cord enclosed within a tubular hyaline
sheath, which two elements are respectively homologous with, or indeed attenuate
prolongations of, the delicate subcutaneous myophan or muscular layer and
superimposed hyaline and structureless cuticle of the zooid's body-wall. In Zoo-
thamnium it is noticeable that the basal portion or main trunk of the branching
pedicle or zoodendrium is devoid of such an enclosed cord, and therefore non-
contractile, and represented by the last only of the two elements just named. This
more simple type of structure partly developed in Zoothamnium characterizes the
entire extent of the compound pedicle of Epistylis and Opercularia, and also the
simpler ones of a numerous host of solitary, short-stalked forms. By Stein it has
been maintained that the indurated lorica of Cothurnia, Vaginicola, and their allies is
morphologically identical with the pedicle of such forms as Epistylis. In some of
these, however, as for example the newly described Pyxicola operculigera, a long sup-
porting pedicle is found co-existent with an indurated lorica, this last-named structure
being evidently, as with the rigid pedicle, a modification or redundant develop-
ment only of the hyaline cuticular layer, the passage of the one to the other being

* ' Proceedings Boston Society Natural History,' vol. x., 1866.

GENUS GERDA. 657

manifested, as already observed, in such types as Opercularia nutans and O. berberina.
In all the loricate species the sheath or lorica is in its earliest state soft and gelatin-
ous, this transient state, considerably exaggerated, characterizing the permanent
condition of the mucilaginous habitations of Ophionella and Ophrydium. The
highly interesting data connected with the more recently observed reproductive
phenomena of this family group are detailed at length in the account given of the
representative genus Vorticella.

Sub -Family I. VORTICELLINA.

Animalcules naked, neither inhabiting sheaths or loricse, nor immersed
within a mucilaginous investment.

GENUS I. GERDA, C. & L.

Animalcules solitary, elongate, subcylindrical, recumbent upon or simply
adherent to submerged bodies, not possessing a distinct sucker or special-
ized organ of attachment as in the genus Scyphidia ; oral system including
a peristomal border, vestibulum, and ciliary disc, as in the ordinary Vorti-
cellcz. Increasing by longitudinal fission. Inhabiting fresh water.

To the single species referred to this generic group by Claparede and Lachmann,
a second form has been recently added by D'Udekem.

Gerda glans, C. & L. PL. XXXIII. FIGS. 36-38.

Body elongate, subcylindrical, highly contractile, three or four times as
long as broad, the wider posterior region, during contraction, assuming
with reference to the then conical anterior part a cup-like form ; surface of
the integument above this posterior portion transversely striate ; oral aper-
ture narrow, pharyngeal cleft deeply prolonged ; endoplast ribbon-like,
placed longitudinally ; contractile vesicle spherical, posteriorly situated,
giving off a slender, canal-like ramification, occasionally branching a second
time, which extends to within a short distance of the ciliary disc. Length
of extended body 1-125".

HAB. — Fresh water, among vegetable debris : near Berlin (C. & L.).

Among the more interesting features of this singular type may be mentioned the
position and structure of the contractile vesicle, its posterior situation being the
converse of what obtains among all the more ordinary members of the Vorticellidan
group, while its canal-like diverticulum finds a counterpart only in the genus Ophry-
dium. Although usually found by Claparede and Lachmann lying about among
water plants and vegetable debris, this animalcule was occasionally observed, as
shown at PI. XXXIII. Fig. 38, to develop a posterior circlet of cilia, and to progress
through the water after the manner of a detached Vorticella.

Gerda fixa, D'Udk. PL. XXXIII. FIGS. 34 AND 35.

Body elongate, its surface entirely smooth, the length when extended
equalling five or six times that of the greatest breadth ; the posterior third
inflated, tapering abruptly and terminating in a blunt point, the two ante-
rior thirds narrower, subcylindrical ; peristome-border thickened, reflected ;

VOL. n. O

658 ORDER PERITRICHA.

ciliary disc convex, moderately elevated ; cilia long and thick, vestibular
cleft produced backwards to a considerable distance, giving origin to
a conspicuous vestibular seta ; contractile vesicle large, spherical, situated
close to the vestibulum ; endoplast band-like, longitudinally disposed.
Dimensions unrecorded. HAB. — Pond water.

This species, as described by D'Udekem,* was obtained in some quantity on
Myriophylium from the neighbourhood of Brussels ; except for the absence of the
mucilaginous investing sheath, its aspect closely resembles the animalcule intro-
duced later on under the title of Ophionella picta. Among the examples figured
by its discoverer, two zooids, PL XXXIII. Fig. 34, are represented as united
by their posterior extremities, the second animalcule having been apparently
developed by the process of longitudinal fission, after the manner of the ordinary
Vorticellce.

GENUS II. SCYPHIDIA, Dujardin.

Animalcules solitary, elongate or pyriform, highly contractile, adherent
posteriorly to foreign bodies, through the medium of a specially developed
acetabuliform organ of attachment ; surface of the integument often trans-
versely or obliquely furrowed ; oral system as in Vorticella.

Although originally instituted by Dujardin and embodied in Perty's system of
classification, Lachmann and Claparede were the first to confer upon this genus
its present distinctive import. With the exception possibly of the Scyphidia rngosa
of Dujardin, the forms included in it by the two former writers are apparently
ordinary Vorticellce which at the time of observation had not developed their charac-
teristic pedicles. In their parasitic habits and mode of attachment Scyphidia limacina
and S. physarum exhibit a bond of affinity with Spirochona, but are at the same
time wanting in the characteristic membraniform spire that so essentially distin-
guishes the members of that genus.

Scyphidia limacina, Lachm. PL. XXXIII. FIG. 32.

Body nearly cylindrical, tapering slightly at either extremity, annulate
transversely ; the posterior extremity truncate, its margin thickened ; peri-
stome narrow, not everted ; ciliary disc narrow, considerably elevated.
Length 1-360" to 1-240".

HAB. — Fresh water, attached to small specimens of Planorbis.

Scyphidia physarum, C. & L.
PL. XXXI. FIGS. 54 AND 55 AND PL. XXXIII. FIG. 31.

Body elongate, highly flexible and contractile, evenly cylindrical
throughout, coarsely annulate transversely ; peristome having a distinct
thickened border ; ciliary disc scarcely exsert, provided with a prominent
central umbilicus. Length 1-200".

HAB. — Fresh water, attached to the skin of Physafontinalis.

This species is readily distinguished from the preceding one by its more
attenuate and perfectly cylindrical outline, and also by the larger relative size of its
peristome, which is completely evertile, and occupies the entire anterior border.

* " Infusoires de la Belgique," 'Mem. Acad Royale de Belgique,' torn, xxxiv., 1864.

GENUS SCYPHIDIA. 659

According to the figures given by Claparede and Lachmann, the annulate and
flexible body presents an almost worm-like contour, and is capable of assuming a
variety of gracefully curved positions. Excellent illustrations of this type, as repro-
duced at PL XXXI. , are given by Quennerstedt.*

Scyphidia rugosa, Duj. PL. XXXIII. FIG. 33.

Body pyriform, the attached posterior extremity most attenuate, surface
of the integument obliquely and coarsely furrowed, pharyngeal cleft deeply
prolonged. Length when extended 1-280".

HAB. — Pond water, among vegetable debris.

This form, in addition to the Vorticella ringens, inclinans, and pyriformis of
Miiller, included in this genus by Dujardin and Perty, as also the Scyphidia patula
of the latter writer, are regarded by Claparede and Lachmann as representing
merely recently attached and imperfectly observed Vorticellce. Scyphidia rugosa,
however, seems to possess claims for recognition as a good species, and is therefore
retained.

Scyphidia Fromentellii, S. K. PL. XXXIII. FIG. 53.

Body elongate-clavate, anteriorly truncate, the posterior extremity con-
tracted, stalk-like, longitudinally plicate ; the remainder of the body smooth ;
possessing apparently two or more contractile vesicles. Length of extended
bodies 1-300". HAB. — Fresh water.

This form is referred with some doubt to Scyphidia rugosa Duj., by De Fromentel,t
from which, however, it is found to differ in every essential detail. De Fromentel
describes it as having a very short, stout, separate footstalk, but according to his
drawings there is no such distinct organ, the attenuate, stalk-like posterior extremity
being soft and fleshy, and becoming entirely obliterated or amalgamated with the
general substance of the body when the animalcule is contracted. His delineations
of this species also indicate this form as possessing several contractile vesicles;
one zooid delineated has two such structures situated anteriorly, and another
specimen one vesicle anteriorly and the other posteriorly placed. A third example
is represented as possessing no less than three contractile spaces, a circumstance
so anomalous in the Peritrichous order that the student is bound to infer that a
misinterpretation of these organs has been made.

Very recently, May 1880, the present author has received, through Mr. Thomas
Bolton, specimens of the Entomostracon Daphnia pulex extensively infested with a
minute sessile Vorticellidan agreeing in all respects, except for the presence of a
single and normally located contractile vesicle, with the species now under discussion
as figured and described by De Fromentel. It was noted in several instances that
the parenchyma was more or less conspicuously vacuolate, the separate vacuoles
presenting much the same size and contour, but not exhibiting the pulsatory motions
of the single anteriorly located contractile vesicle.

Scyphidia inclinans, D'Udk. sp. PL. XXXIV. FIG. 2.

Body elongate-gibbous, highly contractile, rather over twice as long as
broad, dilated centrally, tapering posteriorly and terminating in a small
adherent disc ; peristome-border even, thickened, ciliary disc elevated
obliquely above the peristome ; vestibular cleft produced backwards to the
centre of the body ; parenchyma transparent, granular ; cuticular surface
smooth ; contractile vesicle spherical, situated close to the vestibulum,
* ' Sveriges Infusoriefauna,' 1869. t ' Etudes sur les Microzoaires,' 1876.

O 2

660 ORDER PERITRICHA.

immediately beneath the peristome-border. Animalcule when retracted
bent to one side and transversely puckered on its shorter concave border,
the anterior margin projecting centrally as a small snout-like prominence.
Dimensions unrecorded. HAB. — Fresh water, on Nais.

No complete diagnosis of this species is given by D'Udekem * in his brief
reference to it under the title of Gerda inclinans, he being rather doubtful whether or
not to regard it as a variety only of either the Scyphidia ringens of Dujardin or as
the single and immature condition of his own Epistylis Jubifids. The excellent
figure, however, that accompanies his brief description, and in accordance with
which the present diagnosis is framed, leaves no doubt as to the specific distinction
of this type from either of the two forms mentioned. Its occurrence abundantly
always as separate individuals, apart from the basal sucker, sufficiently distinguishes
it from the Epistylis, while the smooth surface of the integument assists in separating
it from Dujardin's type.

GENUS III. SPIROCHONA, Stein.

Animalcules solitary, elongate-fusiform or campanulate, attached pos-
teriorly by an adherent sucking-disc or acetabulum ; peristome developed
wholly or in part as a hyaline, spirally convolute, membranous funnel,
the right or left limb of which descends into the oral fossa ; endoplast
ovate or elongate ; increasing by gemmation or transverse fission. Inhabit-
ing fresh, salt, or brackish water.

The remarkable funnel-shaped modification of the anterior region in this and
the succeeding genus may be regarded as an exaggerated development of the
membranous collar-like extension of the peristome-border in Opercularia and Lage-
nophrys hereafter described. All the species so far discovered occur as parasites
or commensals upon other aquatic animals. To the two forms originally introduced
by Stein a third, S. tintinnabulum is here added.

Spirochona gemmipara, Stein. PL. XXXIII. FIGS. 43-49.

Body elongate-fusiform, narrowing at both extremities, attached pos-
teriorly by a circular, radiately striate, adhesive disc ; peristome contracted
at its base, produced into an elevated, funnel-shaped, spirally convolute
lamina of three turns, whose height nearly equals that of one-half of the
entire body. Length of body 1-750" to 1-216".

HAB. — Fresh water, attached to the ova-capsules of Gammarus pulex
and various Entomostraca.

The structure and development of this species is the subject of a valuable
communication contributed by Professor R. Hertwig to the ' Jenaische Zeitschrift,'
Bd. ii., 1877, in which it is shown that the animalcule is adherent to its fulcrum
of support through the medium of a special sucker-like modification of its basal
extremity, in place of being mounted on a short and simple pedicle, as originally
described by Stein. The production of new zooids by gemmation is accompanied
by the separation and embodiment within the gemma of a portion of the parent
endoplast, an exhaustive account being given by Hertwig of the successive aspects
exhibited by the bud during its growth to the adult form. Certain of these phases,
as shown at PI. XXXIII. Figs. 45 and 46, resemble in a remarkable manner such a

* ' Infusoires de la Belgique,' 1864.

GENUS SPIROCHONA. 66 1

simple Hypotrichous type as Chlamydodon, and at the same time also the ciliated
embryos of Hemiophrya gemmipara, Dendrocometes paradoxus, and other Acinetidse.

Spirochona Scheutenii, Stein. PL. XXXIII. FIGS. 50-52.

Body elongate, subfusiform, narrowed posteriorly ; organ of attachment
apparently agreeing with that of S. gemmipara, but this not yet definitely
ascertained ; peristome produced as a wide, funnel-like, spiral lamina,
having only a single horizontal turn, and bearing on one side numerous
fimbriated processes. Length of body 1-300".

HAS. — Salt or brackish water, attached to Gammarus marinus and
other Entomostraca.

Further investigation will probably demonstrate that this species, in common
with the preceding form, is adherent to its basis of support through the medium of
a sucker-like expansion of its posterior extremity, instead of by a short pedicle, as
described by Stein. A closely corresponding, but even more strongly marked,
fimbriated ornamentation of the border of the infundibulum, occurs in the type
hereinafter described under the title of Stylochona coronata. There can be but little
doubt that the so-called Vaginicola figured by Messrs. Bates and Westwood,* repro-
duced at PI. XXXII. Figs. 51 and 52, found attached to the natatory appendages of
Gammarus marinus, is synonymous with this type. An identical or closely allied
species has likewise, they record, been reported by Mr. Rentsch as occurring on
Gammarus ornatus. According to the figures given by the two first-named authorities,
the species is attached in a sessile or sub-sessile manner to its fulcrum of support.

Spirochona tintinnabulum, S. K. PL. XXXIII. FIGS. 39-42.

Body elongate-campanulate, tapering posteriorly, and attached by a
well-defined adherent disc, widening out and attaining its greatest breadth
at its anterior border ; membranous funnel springing from the inner margin
of a well-defined peristomal border, equal in height to one-half the length
of the body, rising abruptly and elevated in a tongue-like manner, not
constituting more than a single turn, its right limb descending into the oral
fossa ; endoplast elongate, band-like ; the posterior third of the body
frequently enclosing a subtriangular hyaline corpuscle ; the cuticular sur-
face usually finely striate transversely. Length of body 1-650".

HAB. — Fresh water : on the epidermis and branchial appendages of
young newts, Triton cristata.

This species differs essentially from the previously described representatives of the
genus Spirochona in the form of its body, which is campanulate, and more like that
of an ordinary Vorticclla. In the two former species there is, moreover, a strongly
marked constriction between the body and the expanding funnel, which is entirely
wanting in the present instance. A still more important character is associated
with the funnel itself, which in the new species here introduced takes its origin
within the margin of a well-defined peristome, instead of being continuous with the
general surface of the body as represented in each of Stein's types, and it being the
right limb, as in the more ordinary Vorticellidae, that descends into the oral fossa.
Histologically considered, the convoluted funnel of Spirochona would seem to
represent the peristome itself drawn out into a membranous spire, the third or basal

'British Crustacea,' vol. i. p. 374, 1863.

662 ORDER PERITRICHA.

turn, according to Stein, in ,5". gemmipara being homologous with the peristome
proper. As in S. tintinnabulum this organ is less complex than in either of the pre-
ceding species, the partial retention by the peristome of its typical character, as found
to exist, might be anticipated. Although the funnel is less convolute in this type,
the character it imparts to its general aspect is none the less conspicuous, its height,
one-half that of the body, being indeed greater relatively than in either of the
preceding forms. The examples supplying the figures and description of this
new species were originally met with by the author scattered sparingly over the
whole surface of the integument of a young newt measuring about one inch in length,
taken from a pond at Stoke Newington, London, in August 1871. Those stationed
on the delicate ramifications of the branchial appendages were found to be especially
suitable for examination, a portion of one of these organs bearing several being
removed and subjected to a magnifying power of 800 diameters. The external
surface of the cuticle in this species appears to be less firm than in S. gemmipara
and Scheutenii, the peristome contracting over the mouth and giving the anterior
margin a rounded contour on the withdrawal of the funnel. The wreath of cilia
springing from the base of the funnel are very long and powerful ; a distinct pedicle
could not be detected in any instance, but simply a sucker-like disc of adherence, as
shown by Hertwig to occur in S. gemmipara. Still more recently, July 1878, the
author has obtained this species attached to young newts collected in the neighbour-
hood of St. Heliers, Jersey, and was in this instance fortunate enough to observe
examples undergoing the process of multiplication by transverse fission. In such a
case the membranous funnel and peristome were retracted, and a circlet of long,
powerful cilia developed round the centre of the body, as shown at PI. XXXIII.
Fig. 41 ; the anterior portion with this circlet of cilia became detached and swam off
like a free Vorticella, while the remaining moiety shortly developed a new peristome
and spiral membrane, presenting in its half-matured state the aspect given in
Fig. 42 of the same plate. The elongate, band-like endoplast was observed in one
instance to share in the process of division. Excepting in Ophrydium, division by
transverse fission has not as yet been recorded of any other representative of the
present family group.

Further evidence of the cosmopolitan distribution of Spirachona tintinnabulum is
afforded by the recent receipt of specimens attached to the same specific host,
through Mr. John Hood, from the neighbourhood of Dundee.

GENUS IV. STYLOCHONA, S. K.
(Greek, stulos, stem ; chone, funnel.)

Animalcules solitary, ovate or elongate, mounted on a distinct rigid
pedicle ; peristome differentiated as in the genus Spirockona, forming a more
or less convolute, funnel-shaped, membraniform expansion.

This genus is here instituted for the reception of two marine types which
differ from Spirockona in their possession of distinctly developed, rigid pedicles. Until
quite recently such a structure was supposed to be rudimentarily represented
in the last-named genus. It has, however, been recently shown by Hertwig
of S. gemmipara that such element is there replaced by a somewhat complex
acetabuliform organ of adherence.

Stylochona nebalina, S. K. PL. XXXIII. FIGS. 56 AND 57.

Body elongate, obconical, tapering posteriorly, widest at the anterior
margin, attached by a slender rigid footstalk, often equal in length to one-
third of the entire body ; membranous funnel contracted at its base,
describing little more than a single spiral turn, its terminal border slightly

GENUS STYLOCHONA. 663

. elevated in a tongue-like manner, equal in height to nearly one-half of that
of the body. Length of the body without the funnel and pedicle 1-500".
HAB. — Salt water, on Nebalium bipes.

This species most nearly resembles the brackish-water form Spirochona Scheuteni,
from which, however, it may be distinguished, apart from the possession of a pedicle,
by the obconical instead of fusiform contour of the body, and by the entire absence
of those fibrous or nmbriated processes which ornament one side of the border of
the funnel of that type. A large number of zooids of this new species were found
attached to the thoracic appendages of the Branchiopodous Crustacean Nebalium
bipes collected in St. Clement's Bay, Jersey, in February 1878, having associated
with them as messmates or commensals on the same host, examples of the singular
Trematode Saccobdella nebalia of Van Beneden, and in one instance also, as presently
related, an example of Cothurnia gracilis. Many of the animalcules were under-
going a process of gemmation resembling that already observed of Spirochona
gemmipara. In examples placed in dilute alcohol the membranous funnel retained
its characteristic form, but became unrolled as shown at PI. XXXIII. Fig. 57.

Stylochona coronata, S. K. PL. XXXIII. FIGS. 54 AND 55.

Body elongate-fusiform, somewhat gibbous, about three times as long
as broad; widest centrally, tapering subequally towards each extremity,
mounted on a short, slender, rigid pedicle ; infundibuliform membra-
nous expansion largely developed, forming a convolute spire of two
coils, the external and basal one equal in width to nearly twice the
diameter of the body, its free border fimbriated or fibril late; fibrillae
setaceous, of two sizes, collectively approximating the number of fifty, and
consisting alternately of one longer and four shorter ones, the inner and
apical coil projecting considerably above the basal one, equalling only one-
half of the diameter of the latter, its free border not fimbriate ; vestibular
fossa much dilated, continued backward into a distinct pharyngeal cleft ;
contractile vesicle located close to the vestibulum ; endoplast elongate-
ovate, subcentral. Length of body including the infundibulum 1-400".

HAB.— Salt water, attached to the thoracic appendages of Gam-
marus sp.

This very elegant species was obtained by the author attached in some abun-
dance to the thoracic limbs of a common shore-frequenting species of Gammarus
collected in St. Clement's Bay, Jersey, in the month of March 1:879. It was at first
premised that the animalcule was identical with the Spirochona Scheuteni of Stein,
previously described, the most substantial evidence in favour of such identity being
afforded by the fibrillate ornamentation of the free border of the basal coil of
the collar or infundibulum. A closer acquaintance, however, with the structural
details revealed the existence of so many important distinctive features that it has
been found requisite to confer upon it an independent specific title. In the first
instance, the presence of a well-defined rigid pedicle has indicated the necessity
of separating it from Spirochona proper, in which an acetabuliform modification
of the posterior extremity replaces such an organ of attachment. From Spirochona
Scheutcni, which may eventually prove, as indicated in Stein's drawings, to possess a
short pedicle, it. is to be distinguished, in addition to the conspicuous development
of this last-named organ, by the more attenuate proportions of the body, but most
essentially with relation to both the general and more minute structure of the ante-
riorly developed membranous funnel or collar. This highly characteristic element
in the present form is both far more extensively developed and of more complex

664 ORDER PERITRICHA.

design. In Spirochona Scheuteni it forms a simple uniform horizontal coil of but
one revolution, whose greatest altitude scarcely equals one-quarter of the height
of the body, and with which its greatest width is at the same time subequal. In the
present type there are two distinct revolutions to the membranous funnel, the inner
and lesser one projecting a considerable distance beyond the margin of the external
or basal one, whose height attains to or exceeds one-half of the length of the entire
body, while its diameter at its anterior and everted edge equals no less than twice
that of the subjacent body. The character of the fimbriation of the anterior border
of the external or basal revolution of the membranous funnel is very remarkable.
As developed in Spirochona Scheuteni such fimbriation is ' represented by Stein as
forming a series of less than a score of equal-lengthed setiform processes which
extend along one side only of the expanded structure. In the present species the
homologous elements are developed throughout the whole extent of the basal revo-
lution of the funnel, and are, moreover, of two distinct lengths, numbering fifty or
sixty in all, every fifth element being over twice the length of the four uniform and
comparatively short intervening ones. The entire circle is thus geometrically sub-
divided after the fashion of the dial of a watch, or suggests perhaps still more
significantly the delicately ruled and similarly proportioned subdivisions of a micro-
metric scale. Taken in their entirety, the contour of an animalcule of this species,
with its fusiform body and expanding fimbriated funnel, is not unlike that of the
seed and attached pappus of certain plants, such as Valerian or many of the Com-
positae. Earlier conditions of this type, in which the funnel was yet undeveloped,
were frequently met with, but in no instance could there be detected an example of
lateral gemmation as obtains in the preceding form and in various species of
Spirochona.

GENUS V. RHABDOSTYLA, S. K.
(Greek, rhabdos, rod ; stubs, stem.)

Animalcules solitary, resembling those of Vorticella, but seated on a
rigid, unretractile instead of a flexible, contractile pedicle.

This new genus has been instituted for the reception of a series of animalcules,
several of which have at the time of discovery been described as solitary members
of the genus Epistylis. Their position relative to the last-named group, however, is
evidently parallel to that which subsists between the solitary genus Vorticella and
the compound type of the same form distinguished by the title of Carchesium.
The majority of the species so far discovered are inhabitants of fresh water, and are
mostly remarkable for the extreme shortness of their rigid footstalk; in but two
instances only does this structure exceed the length of the animalcule's body.

Rhabdostyla ovum, S. K. PL. XXXIV. FIGS. 5 AND 6.

Body ovoid, truncate anteriorly when expanded, attached to a slender
rigid pedicle of about one-quarter of its own length ; the surface of cuticle
delicately striate transversely ; ciliary wreath forming two circlets, cilia
very long and strong ; endoplast band-like, curved, disposed longitudinally.
Length of body 1-500". HAB.— Fresh water.

This species was obtained by the author in some abundance on aquatic plants
from a pond in the neighbourhood of Stoke Newington, London. The band-like
endoplast, as shown in the accompanying illustration, was conspicuously developed.
When disturbed or not feeding it closed its peristomal border up tightly, presenting
under such circumstances a perfectly ovoid contour. On several occasions it was
observed, when thus contracted, to rapidly jerk its body backwards and forwards
upon its short pedicle, as though irritated or trying to free itself from some obstruc-

GENUS RHABDOSTYLA. 665

tion. The fine transverse striations of the cuticular surface have been accidentally
omitted by the artist in the figure given of the type.

Rhabdostyla sertularium, S.K. PL. XXXIV. FIGS. 3 AND 4.

Body broadly campanulate, dilated anteriorly when expanded, globose,
with a puckered anterior border when contracted, the cuticular surface finely
striate transversely ; pedicle somewhat stout, variously curved, occasionally
equalling twice the length of the body, but usually much shorter. Length
of body 1-600".

HAB. — Salt water, on the polyparies of Hydroid zoophytes.

The short-stalked variety of this as yet first observed marine representative of
the genus Rhabdostyla was met with by the author in some abundance, in February
1878, attached to the polyparies of the Hydrozoon Aglaophenia pluma, from
St. Clement's Bay, Jersey, one or two animalcules usually occurring in almost
uninterrupted order on the lowermost spur of each calycle of this elegant little
zoophyte. The pedicle, under high magnification, exhibited what appeared to be
a central cavity, corresponding in this respect with that of Epistylis flavicans. When
closing up, the animalcules simply contract into a spherical form upon their rigid
pedicles. On one occasion only was an endoplast-like structure observed ; it
was in that instance ovate in shape and on the point of dividing transversely.
Examples of this species, characterized by the possession of stalks which nearly
equalled twice the length of the body, PI. XXXIII. Fig. 4, were subsequently
obtained from St. Aubin's Bay, in the same island.

Rhabdostyla brevipes, C. & L. sp. PL. XXXIV. FIG. 8.

Body subcylindrical, attenuate, about three times as long as broad ;
cuticular surface smooth, but presenting several transverse folds posteriorly
when contracted ; pedicle exceedingly short, about one-tenth the length of
the entire body ; endoplast oval, subcentral. Length of body 1-300".

HAB. — Fresh water, on aquatic insects.

Claparede and Lachmann, conferring upon this species the title of Epistylis
brevipes, have figured and described it only in its retracted state, in which the
posterior extremity is plicate in three folds, and the anterior border contracted in a
snout-like form. Under the conditions noted, it closely resembles a single zooid
of Epistylis plicatilis, but possesses a longer and more cylindrical outline. The
species was originally found in some abundance on the larvae of various Diptera in
the Berlin Zoological Gardens, the individual zooids being fixed very closely to each
other. Its discoverers remark that, if this type is persistent, it merits, as recognized
in this volume, a new generic title.

Rhabdostyla nebulifera, From. sp. PL. XXXIV. FIGS, n AND 12.

Body subglobose, anteriorly truncate, surface smooth ; pedicle short,
about one-half as long as the body, fimbriate at its point of attachment,
expanded in a cup-like manner where it joins the animalcule's body.
Length of body 1-200". HAB. — Fresh water.

This species is described by De Fromentel * as Epistylis nebulifera. One of the
two figures given by him represents an example dividing by longitudinal fission — a
phenomenon not yet witnessed in the species examined by the author.

' Etudes sur les Microzoaires,' 1876.

666 ORDER PERITRICHA.

Rhabdostyla sphgeroides, From. sp. PL. XXXHf. FIG. 10.

Body when expanded forming through the dome-like elevation of the
ciliary disc, above the peristomal margin, an almost perfect sphere ; slightly
contracted beneath the peristome ; the cuticular surface smooth ; pharyngeal
cleft curved, greatly prolonged ; peristomal cilia long and stout ; pedicle
moderately stout, one-half the length of the body, considerably expanded
at both its distal and proximal extremities. Length of body 1-400".

HAB. — Fresh water.

While somewhat resembling the last species, it may be readily distinguished from
it by its smaller size and the dome-like elevation of the ciliary disc. According
to De Fromentel's illustration, the contractile vesicle is larger and located nearer the
centre instead of towards the peristomal region of the body as in the preceding
form. Its discoverer originally described this animalcule as a species of Epistylis.

Rhabdostyla ringens, From. sp. PL. XXXIV. FIG. i.

Body elongate-conical or trumpet-shaped, attenuate, over twice as long
as broad, widest at the dilated anterior margin, gradually tapering towards
its point of juncture with the pedicle ; cuticular surface smooth, colour
brown ; pedicle short, slender, about one-third the length of the body.
Length of body 1-300'. HAB. — Fresh water.

De Fromentel refers this species, under the title of Epistylis ringens, with doubt
to the Vorticella ringens of Chevalier, of which an illustration but no description has
yet been given.

Rhabdostyla longipes, S. K. PL. XXXIV. FIG. 29.

Body elongate-campanulate, more attenuate posteriorly, about twice as
long as broad when expanded, symmetrically ovate in its contracted state ;
parenchyma transparent, finely granulate ; cuticular surface smooth ; pedicle
slender, sinuous, two or three times as long as the body, enclosing centrally
an even series of minute granular particles. Length of body 1-350".

HAB. — Pond water, social.

This species was found by the author in company with Vorticella campanula, in
February 1879, attached in small social patches to a Water Crowfoot taken from a
pond near St. Heliers, Jersey. The rigid footstalk in all cases enclosed, as repre-
sented in the accompanying illustration, an even line of granular particles most
nearly resembling, except for the absence of colour, what obtains in Vorticella picta.

GENUS VI. PYXIDIUM, S. K.
(Latin, pyxidium, a little box.)

Animalcules solitary, ovate, adherent posteriorly through the medium
of a simple rigid pedicle ; ciliary disc, as in the genus Opercularia, separate
from the peristome and attached to one side of the oral fossa.

This genus is instituted for the reception of such solitary animalcules as accord
in structure with the zooids of the compound genus Opercularia, and towards which
it occupies the same near relationship that subsists between Rhabdostyla and
Epistylis, or Vorticella and Carchesium. Two species only, both inhabiting fresh
water, have as yet been observed.

GENUS VORTICELLA. 667

Pyxidium cothumoides, S. K. PL. XXXIV. FIG. 7.

Animalcules ovate, somewhat gibbous, twice as long as broad ; peristome
margin truncate, entire ; ciliary disc minute, furnished with two circlets of
cilia, projecting conspicuously beyond the border of the peristome ; surface
of cuticle smooth, considerably indurated ; endoplast linear, curved, longi-
tudinally placed ; contractile vesicle adjacent to the vestibulum ; pedicle
very short, less than one-quarter the length of the body, which it supports
in a slightly inclined or oblique position. Length of body 1-500".

HAB. — Fresh water, attached to Entomostraca.

The examples which served as a basis for this new species and genus were
obtained by the author, in March 1874, attached in considerable quantities, singly
or in small groups, to the carapace of a species of Cypris. Deprived of its short
pedicle and with its body laterally attached, this type would have to be referred to
the genus Lagenophrys, and may be regarded as intermediate between Opercularia
and that genus. The zooids on contracting exhibit a nodding action, and become
bent obliquely on their short pedicles, but in consequence of the rigidity of the
integument scarcely alter their general contour. Although looked for, no distinct
membranous collar, as in Opercularia, could be detected. More than twenty
specimens of this animalcule were observed on a single Cypris obtained from a
pond at Stoke Newington. Some of the older zooids were a pale amber colour,
the younger ones being perfectly transparent.

Pyxidium inclinans, Mull. sp. PI. XXXIV. Fig. 9.

Body erect, ovate-cylindrical, posterior extremity rounded and widest ;
the cuticular surface finely striate transversely; peristome-border longi-
tudinally plicate ; ciliary disc protrusible to a considerable distance beyond
the margin of the peristome, bearing one ciliary circlet, supplemented by
a collar-like membrane ; pharyngeal cleft conspicuous, prolonged through
two-thirds of the length of the body ; pedicle very short and stout ; body
when contracted transversely folded posteriorly, remaining erect or bent
to an entirely recumbent position. Length of body 1-300".

HAB. — Fresh water.

This species, introduced by De Fromentel * under the title of Scyphidia me/mans,
and identified by him with the Vorticella indinans of O. F. Miiller, is apparently
referable to the present genus. From the form last described it may be easily
distinguished by its more regularly ovate form and by the various transverse and
longitudinal striae and plications of the cuticular surface. No details of the special
habitat of this variety are recorded by De Fromentel, but the two examples are
apparently attached to a Confervoid filament.

GENUS VII. VORTICELLA, Linnaeus.

Animalcules ovate, spheroidal or campanulate, attached posteriorly by a
simple, undivided, more or less elongate and contractile, thread-like pedicle ;
the pedicle enclosing an elastic, spirally disposed, muscular fibrilla, and
assuming suddenly on contraction a much shortened and usually cork-
screw-like contour; adoral system consisting of a spirally convolute

* ' Microzoaires,' 1876.

668 ORDER PERITRICHA.

ciliary wreath, the right limb of which descends into the oral or vestibular
fossa, the left one obliquely elevated and encircling the so-called rotatory or
ciliary disc ; the entire adoral wreath contained within and bounded by a
more or less distinctly raised annular border — the peristome — between
which and the elevated ciliary disc, on the ventral side, the widely
excavated oral fossa or vestibulum is situated ; the vestibulum further con-
tinued into a conspicuous cleft-like pharynx, and finally terminating in a
narrower tubular oesophagus, the junction of which with the pharynx
exhibits an ovate and thick-walled dilatation ; anal aperture opening into
the vestibular fossa, the upper wall of this same fossa usually bearing
apparently a more or less distinct setose appendage known as the vesti-
bular seta or "soie de Lack mann" \* contractile vesicle single, spherical,
situated close to and debouching into the vestibulum ; endoplast more or
less elongate and band-like; zooids multiplying by longitudinal fission,
and gemmation, and by the development of germs through the disruption
of the endoplast. Inhabiting salt and fresh water.

The Vorticellce. or "Bell- Animalcules" include, perhaps, the most familiar and
graceful representatives of the entire class of the Ciliata. All the members of the
genus are readily distinguished by their transparent wineglass- or bell-shaped bodies
and accompanying elastic, thread-like pedicles. These organs of attachment during
life are in many species in an almost constant state of alternate contraction and
prolongation, a circumstance which, in connection with a large colony of these elegant
microscopic beings, produces a spectacle of unparallelled beauty and activity. The
details of the adoral system, and more especially those relating to the cesophageal and
pharyngeal regions as here embodied, have been demonstrated more particularly by
Richard Greeff,t and are now admitted as fundamentally identical throughout all the
members of the Vorticellidce. The central muscular thread or fibrilla that gives to the
stalk of Vorticella its characteristic power of contraction is, as indicated by so early an
authority as Ehrenberg, disposed in an extended spiral form within its hyaline outer
sheath, and is also now demonstrated to be continuous with a delicate muscular
sheet or layer that passes up into the walls of the body and immediately underlies
the cuticle. More correctly, the pedicle in its entirety may be described as an
attenuate posterior prolongation of the subcuticular muscular or myophan system,
enclosed throughout its length, as in the body, within a tubular sheath of the
hyaline, structureless cuticle. In diverse species of the genus Vorticella a con-
siderable amount of variation is found to exist in the ultimate construction of the
central muscle-like fibre of the characteristic contractile pedicle. In many of these,
as seen under high magnification, a coarse granulation of this element, sometimes
produced more conspicuously along one edge or in a spiral manner around the
central axis, is distinctly visible ; while in some few, such as Vorticella picta and
V. appuncta, larger refringent corpuscles of a brilliant hue are found imbedded in
it. In Vorticella nebulifera, as represented by Everts, see Woodcut, p. 674,
this central contractile fibrilla exhibits a longitudinally striate pattern ; while in
V. margaritifera, according to De Fromentel, it is distinctly striate in a transverse
direction. In addition to the longitudinal muscular fibrillas, Greeff has endeavoured
to show that the transverse striae that form so conspicuous a feature in many repre-
sentatives of the genus are also of a muscular character, and describe a continuous
and closely set spiral convolution around the animalcule's body. This last inter-
pretation is not, however, elsewhere supported ; overwhelming evidence, on the

* For a more detailed account of this appendage, see family Vorticellidse, p. 656.
t " Untersuchung liber den Bau und die Naturgeschichte der Vorticellen, " ' Wiegmann's
Aichiv,' Bd. xxxiii., 1870.

GENUS VORTICELLA. 669

other hand, tending to demonstrate that such markings are mere superficial annula-
tions of the cuticle. The entire absence of these transverse markings in a very
large proportion of the numerous species, sufficiently indicates their non-essential
nature, while further evidence of their correct relegation to the category of surface
ornamentation is afforded by the species here described under the title of Vorticella
monilata, in which the more usual linear markings are replaced by a closely set
series of bead-like elevations.

The phenomena pertaining to the various processes of reproduction, as mani-
fested by the Vorticellida generally, and typically by the representative genus
Vorticella, are of high interest, and may, at this point, be appropriately narrated.
As among all members of the infusorial tribe, that mode of increase which is
most prominently and commonly exhibited takes the form of simple fission, one
primary zooid or animalcule giving rise by more or less frequently repeated sub-
division to an innumerable progeny of daughter zooids. This fissive process in
the genus Vorticella, and, so far as known, with the exception only of the genera
Spirochona, Lagenophrys and Ophrydium, throughout the Vorticellidas, takes a longi-
tudinal direction. The circumstances attending this mode of increase are nevertheless
considerably more complex than those which obtain among the various infusorial groups
previously described, and are well exemplified in connection with the delineations of
this process in Vorticella marina as given by Greeff and reproduced at PI. XXXV.
Figs. 1-5. The initial step towards the consummation of this duplicative act is
accomplished through the withdrawal by the animalcule of its ciliary disc and assump-
tion of a subspheroidal or pyriform contour, as under the ordinary conditions of
contraction. The body itself has by this time become abnormally dilated, and
presently develops an indentation or notch in the centre of its anterior border. The
contracted and lunate vestibular cleft divides into two equal halves, or as observed
by the author in the case of Vorticella ncbulifera — such observation being also in
accord with that of Everts — becomes entirely obliterated, a new vestibular cleft and
oral system being developed on each side of the median line. A line of division is
now gradually produced from the pre-existing anterior median notch, through the
centre of the animalcule's body, cleaving in twain in its onward passage both the
spheroidal contractile vesicle and the band-like endoplast. The ultimate result of
this cleavage process is the production upon the single stalk of two zooids similar
to the original or parent unit, and differing but little from it in point of calibre.
While one zooid remains attached to the parent pedicle, and expanding its newly
developed peristome pursues its ordinary food-ingesting avocations, its duplicate
undergoes a further and highly characteristic metamorphosis. The peristome
border more usually remains closely contracted, while a new element is introduced
through the development round the posterior region of the body of a girdle of
powerful vibratile cilia. These, by their vigorous and continued motion, produce
an abnormal tension on the thinnest and weakest point, namely at the junction
of the body with the stalk ; this finally giving way, the animalcule is launched into
the surrounding water, and propels itself whither it pleases with the assistance of
its posteriorly developed ciliary girdle. This nomadic phase of existence is, how-
ever, of but short duration ; the natatory motions of the zooid grow more languid,
and it soon resorts to creeping over adjacent objects with its posterior border and
ciliary circlet applied to their surface, presenting under such auspices, as shown
at PI. XXXIV. Fig. 1 8, a considerable resemblance to an ordinary repent Tricho-
dina. Having at length lit upon a spot adapted to its tastes or exigencies, it adheres
to it by its posterior extremity, and the girdle of temporarily developed locomotive
cilia becomes absorbed and entirely obliterated. The peristome-border with its
enclosed ciliary disc is now everted, and the stalk rapidly developing, the animalcule
is soon in no way distinguishable from the normal sedentary zooid that gave it
origin.

The temporary locomotive phase of Vorticella just described, is, however, by
no means exhibited only by zooids liberated through the process of longitudinal
fission. The ordinary singly attached animalcules, if submitted to uncongenial
conditions, develop in a like manner a supplementary girdle of cilia, and becoming

670 ORDER PERITRICHA.

disconnected from their pedicles, swim off in search of a more suitable location.
Similar phenomena are furthermore common to all the compound stock-building
representatives of this family group, in which, as familiarly illustrated by such
examples as Epistylis digitalis and E. anastatica, the entire branching zooden-
drium may become as bare as a leafless tree, through a parallel migration of its
associated zooids, within a brief interval of its transfer from its native pond to the
stage of the microscope. A peculiar modification of this migratory phenomenon
obtains in the genus Zoothamnium, where, in certain species, zooids of abnormal
size are periodically produced, which developing in a similar manner a posterior
circlet of locomotive cilia, swim off to lay the foundations of new colonies. In
intimate connection with the process of equal or subequal longitudinal subdivision
already recounted, has to be recorded the production, through a closely parallel
course of development, of the comparatively minute bud-like zooids, whose ultimate
mission is not that of establishing itself independently and growing to the parent
form, but — as first demonstrated by Stein, and since confirmed by the more recent
investigations of Greeff, Engelmann, and various other authorities — of contracting
intimate fusion or genetic union with some other normally developed sedentary
animalcule. Such a more minute animalcule or microzooid is, as shown at PI. XXXV.
Figs. 10-12, usually developed under conditions precisely parallel to those already
related of ordinary fission ; not unfrequently, however, these microzooids are pro-
duced through a further repetition of the duplicative process, in connection with
one of the two equal or subequal primarily separated moieties, the result being,
as shown at PI. XXXIV. Fig. 230 and PI. XXXV. Fig. 19, the production of two
or it may be as many as eight such microzooids, each with its posteriorly developed
ciliary girdle, that remain temporarily attached to the parent stalk.

In the compound stock-form Epistylis flavicans, according to Greeff, whose illus-
trations are reproduced at PI. XXXVIII. Fig. i rr, the entire parent animalcule
becomes subdivided into four or eight locomotive microzooids. Having separated
themselves from the parent stem, these microzooids swim hither and thither, until
they come into contact with a normal sedentary Vorticella^ to whose lateral periphery
it then affixes itself by its anterior or oral pole, and gradually boring its way into its
interior, the two becoming indissolubly and indistinguishably united. The accom-
plishment of this conjugative act is undoubtedly directly comparable with and
analogous to the union of the male and female elements, or germ-cell and sperm-cell,
of the higher Metazoa. The phenomena succeeding such conjugation are, further-
more, physiologically, and indeed morphologically, identical. While it is now made
manifest that the sexual theory, as originally propounded by Balbiani, and referred
to at length in the preceding volume, see page 94, cannot be maintained, and in
which distinct sexual elements were premised to be represented in, and exchanged
between, each conjugating zooid, the ovum and spermatozoon are here practically
represented in each animalcule, themselves simple cells, and whose union confers,
in a like manner, upon the former a renewed capacity of multiplication by binary
subdivision. According to the recent investigations of Biitschli and Engelmann, it
is only such a rejuvenating influence, or capacity to further subdivide by longitudinal
fission, that is accomplished by the conjugative act. It would seem highly probable,
however — the supposition being further substantially supported by what follows upon
the conjugative process among the Flagellata— that if not directly, yet more or less
remotely, this genetic union of the migrant and sedentary zooids brings about that
mode of multiplication by encystment, and the subdivision of the entire body into
sporular elements, that yet remains to be described. This phenomenon, while pre-
viously recorded by numerous investigators, has been as yet traced with the nearest
approach to completeness by Eduard Everts.* As reported by the last-named
authority in the case of Vorticella nebulifera, it is an animalcule set free by the
process of ordinary longitudinal fission, as already described, that enters upon this
reproductive phase of encystment. It, however, takes place quite as, if not more,

" Untersuchungen an Vorticella nebulifera" 'Zeit. Wiss. Zool.,' Bd. xxxiii., 1870.

GENUS VORTICELLA. 671

frequently in association with an ordinary undivided 20oid that has become
liberated from its stalk ; or, as more rarely happens, the same zooid may enter upon
this condition of encystment without becoming separated from its pedicle. The sub-
sequent metamorphoses are in all cases identical. The animalcule contracts into
a subspheroidal form, and secretes around it a hyaline, chitine-like, ovate or sub-
spheroidal cyst, whose surface is frequently ornamentally facetted. The oral system,
contractile vesicle, and, with the exception of the nucleus or endoplast, all other
distinct features of the enclosed animalcule become next entirely obliterated. The
band-like endoplast, which previous to the process of encystment had already be-
come abnormally conspicuous, represents now the only essential differentiated
structure, and it is out of this that the sporular elements are evolved. Increasing in
dimensions at the expense of the surrounding protoplasm, it grows relatively larger,
much convoluted, or even branched. It next becomes constricted at regular
intervals, presenting a moniliform appearance, and finally separating at each con-
striction, the cyst is more or less completely filled with subspheroidal spore-like
fragments. Becoming matured, these sporular bodies are discharged, through rupture
of their capsule, as minute ovate or pyriform free-swimming animalcules, possessing
an anterior crown of cilia, which are likened by Everts to Trichodina (Halteria)
grandinella, but more correctly resemble the adult form of the genus Strombidium.
These free-swimming embryos multiply abundantly by transverse subdivision, incept
food by an oral aperture developed in close proximity to the anterior ciliary wreath,
and finally, becoming languid in their motions, attach themselves by their oral pole
to some submerged object. The pre-existing oral aperture and accompanying cilia
are now obliterated, new ones, as in an adult Vorticella, are developed at the opposite
extremity, and the attached portion, gradually lengthening, assumes the contour and
characters of the ordinary contractile pedicle. Illustrations of all the more charac-
teristic phases of this developmental process, as given by Everts, are reproduced
at PL XXXV. Figs. 33-46.

An interesting example of the above reproductive form of encystment has been
recently recorded by Professor G. J. Allman,* in connection with a compound
Vorticellidan, apparently a species of Epistylis, obtained by him from a pond in
Brittany. Of this he states : " Among the ordinary zooids which are grouped in
spherical clusters on the extremities of the branches, there were usually some which
had become encysted in a very remarkable way, and without any previous conjuga-
tion having been noticed. These encysted forms were much larger than the others,
and had assumed a nearly spherical shape. The peristome and ciliary-disc had
become entirely withdrawn ; the contractile vesicle was still obvious, but had ceased
to manifest contractions ; brownish spherical corpuscles with granular contents,
probably the more or less altered chlorophyll-granules of the unencysted zooid (food-
material ?), were scattered through the parenchyma ; and the nucleus was not only
distinct, but had increased considerably in length. Round the whole a clear gelati-
nous envelope had become excreted. In a later stage there was formed between the
gelatinous envelope and the cortical layer of the body a strong, dark brown, apparently
chitinous case, the surface of which, in stages still further advanced, had become
ornamented by very regular hexagonal spaces with slightly elevated edges. In this
state the chitinous envelope was so opaque that no view could be obtained through
it of the included structures, and in order to arrive at any knowledge of these it was
necessary to rupture it. The nucleus thus liberated was found to have still further
increased in length, and to have become wound into a convoluted and complicated
knot. Along with the nucleus were expelled multitudes of very minute corpuscles,
with active Brownian movements. In a still later stage the nucleus had become
irregularly branched, and at the same time somewhat thicker and of a softer con-
sistence, while finally this element had broken up into spherical fragments, each
with an included corpuscle resembling a true cell-nucleus, the place of a nucleolus
being taken up by a cluster of minute granules." It is clearly evident that the form

* Brit. Assoc. Reports, 1873, and President's Address to the Linnaean Society, 1875.

672 ORDER PERITRICHA.

of reproduction just recounted represents but a slight modification only of the
phenomenon of encystment and endogenous multiplication so prevalent among the
class Flagellata, and where, as exemplified more especially in such forms as Heteromita
lens, Spirornonas angustata, and Etiglena viridis, such a reproductive process may
take place either with or without the intercalation of a conjugative act. The only
recognizable distinction between the two correlated processes is manifested by the
fact that, while in the Flagellate species the reproductive germs or spores are pro-
duced by the segmentation of the complete body-mass pari passu with that of
the nucleus, and a portion of which is enclosed within each protoplasmic fragment,
after the manner of normal cell-multiplication, in the case of Vorticella the endo-
plast alone, increasing at the expense of, and assimilating the body protoplasm into
its own substance, undergoes segmentation. The result ultimately arrived at is
in both cases precisely identical, the mode of their accomplishment alone being
divergent. As it obtains in the group of the Vorticellidae, this reproductive process
may be further accepted as yielding a condition intermediate between that simplest
form of endogenous multiplication, just cited as encountered among the simpler
Flagellata, and that more complicated form which obtains in the Heterotrichous
genera Stentor, Spirostomum, and some few Peritricha, such as Didinium. In all of
these the band-like endoplast or nucleus assumes the character of an internal
proliferous stolon, the germs produced through its disintegration being liberated
independently, and in association with the unimpaired maintenance by the parent of
its normal form and vital functions.

In addition to the reproductive form of encystment just recounted, that simpler
phase of the same process, assumed merely as a temporary or " resting state " during
seasons of drought or other uncongenial conditions, is in common with almost all
other infusorial forms, abundantly displayed by the members of the present genus.
An illustration of this phenomenon, as exhibited by Vorticella infusionum, is repre-
sented in company with the encysted and sporular conditions of various Flagellate
types, as attached to hay-fibres, in Fig. i a a of PI. XI. Not unfrequently, as
obs'erved by Stein and Everts, these encysted Vorticdla fall a prey to parasitic
flagellate organisms, apparently allied to or identical with Heteromita caudata,
which having gained access to the body of their host previous to its encystment,
subsequently escape from the cyst in place of the original tenant, much after the
manner that a brood of Ichneumon-flies swarms out of the pupa case of some
Lepidopterous insect.

A rare form of conjugation, hitherto unnoticed, has been reported by Stein and
Claparede and Lachmann, in which two, or — according to the last-named autho-
rities,— it may be even three, sedentary zooids accomplish an intimate union with
one another, and, developing a posterior circlet of cilia, become detached from their
stalks and finally enter upon an encysted state. Examples of this form of conjuga-
tion, as exhibited by the cosmopolitan type Vorticella microstoma, are reproduced
from Claparede and Lachmann's work at PI. XXXV. Figs. 22-24. Both here and
in the case of the conjugation or zygosis between a migrant and sedentary zooid,
the tendency to conjugate, while of rare occurrence, spreads like an epidemic
throughout every neighbouring colony, and may therefore, where once detected, be
usually examined in detail in a mass of instances.

On account of the very considerable number of species that have been added
as the result of recent investigation, and of the great similarity in external contour
which in many cases subsists between them, the genus Vorticella has undoubtedly
become one of the most numerically abundant specific groups of the entire infusorial
class, while its members present to the working microscopist difficulties in connec-
tion with their correct identification closely parallel to those experienced by the
botanist in association with the genus Carex. In order to lighten his labours as far
as possible in this direction, 'a scheme, supplemented by PI. XLIX., is here sub-
mitted, which, while susceptible of considerable extension and improvement, will
afford a convenient clue to the elimination of the more formidable obscurities. As
a preliminary step towards the accomplishment of the end in view the some three
dozen or more species belonging to the^enus are divided into two primary sections,

GENUS VORTICELLA. 673

the one containing those forms in which the cuticular surface is smooth or glabrous ,
and the other those in which with the moderate magnification of three or four
hundred diameters only, transverse striae or other surface ornamentations are clearly
perceptible. Both of these two sections admit of subdivision into subordinate groups
based upon the contour of the body of the zooids as presented in their most typical
or fully expanded state. Among the most abundant smooth cuticled series it will
be found that the body exhibits three leading modifications. In the first of these it
is simply ovate or elongate, having a length equalling at least twice that of the
greatest width, while the frontal margin is but slightly dilated. The characteristic
features of this series attain their highest development in such forms as V. cucullus
and V. quadrangularis. In the second series the body is normally broadly cam-
panulate or bell-shaped, having the frontal margin much dilated, and often exceeding
in diameter the longitudinal measurement of the animalcule. The Vorticella cam-
panula of Ehrenberg typifies this section, the V. citrina and V. patellina affording
further examples of this group in which the peristome-border is dilated to such an
extent as to approach a contour to which in botanical terminology the title of
"hypocrateriform" would be applied. In a third, and as at present known, not very
extensive series, fitly typified in the recently described Vorticella spherica of D'Ude-
kem, the body in its most complete state of expansion presents an almost perfectly
spheroidal contour. In that section, distinguished by the striate or otherwise ornate
character of the cuticular surface, no representative of the spheroidal series has been
as yet recorded, while the Vorticella elongata and V. appuncta of De Fromentel may be
cited respectively as characteristic examples of the elongate-conical and broadly cam-
panulate groups. To the last-named series has also to be relegated the Vorticella
monilata of Tatem, remarkable for the bead-like elevations which replace the simple
striae of the more ordinary species. That in many instances the several groups as
above distinguished, and more especially the conical and campanulate series, closely
approach and amalgamate with one another, is readily admitted, a hard and fast line
of separation being indeed entirely arbitrary and artificial. Applied, however, in
its broad sense, and aided by the special characteristics noted in the technical
diagnoses, the recognition and identification of the various specific forms, with the
assistance of this scheme, is greatly facilitated.

For the future guidance of investigators of this exceedingly attractive generic
group, attention may be profitably directed to the very incomplete data from which
in many cases the specific descriptions given in this treatise have been framed,
and to which it is exceedingly desirable that more comprehensive details should be
added. The large number of new species recently introduced by De Fromentel *
are particularly unsatisfactory in this respect. In not a single instance does he
record whether the animalcule figured is social or solitary in its habits, whether a
denizen of ponds, running water, or infusions, while in but few instances even is
the comparative length of the supporting pedicle indicated in his drawings or
mentioned in the accompanying text. All of these characteristics are of high
importance, and should be registered in drawing up an account of a doubtful or
supposed new species. The form assumed by the body in its contracted state
should likewise receive attention, this phase, as exemplified in Vorticella citrina and
V. telescopica, often yielding data of as high value for specific discrimination as those
afforded by the fully expanded zooids.

A.— CUTICULAR SURFACE SMOOTH.

* Bodies conical or elongate.

Vorticella nebulifera, Ehr.
PL. XXXIV. FIG. 20, PL. XXXV. FIGS. 32-47, AND PL. XLIX. FIG. i.

Body when extended conical-campanulate, somewhat gibbous, about
three times as long as broad, tapering posteriorly, slightly constricted

* ' Etudes sur les Microzoaires,' 1876.
VOL. II. P

674

ORDER PERITRICHA.

beneath the obliquely set and moderately dilated peristome ; contour when
contracted pyriform, with the anterior border lobate ; parenchyma trans-
parent, colourless ; cuticular surface smooth, soft and plastic, often puckered ;
pedicle slender, four or five times longer than the body. Length without
pedicle 1-570" to 1-280".

HAB. — Pond-water, forming social clusters on the roots of Lemn<z and
other aquatic plants.

This species may be abundantly obtained at all seasons of the year under the
conditions above indicated. By Ehrenberg it has been identified with the Vorticella
convallaria, in part of Linnaeus and O. F. Miiller, and also with the Vorticella nebu-
lifera of the last-named authority. On referring, however, to Miiller's original account
of the type agreeing in name with the present one, the author finds that it relates
to a marine species having a much wider bell-like contour, which has not apparently
been since observed. That the title of nebulifera belongs properly to the marine
animalcule is evident, though custom has so long associated it with the present
fluviatile form, that the introduction of a new title for the distinction of the latter
type appears undesirable. As seen under the high magnification of six or eight
hundred diameters, the cuticular surface is shown to be finely striate transversely,
but it does not exhibit such character with one of two or three hundred only,
which is employed for establishing that distinction between the smooth and con-
spicuously striate types here adopted as an aid to their specific identification. Full
details of the reproductive phenomena of the present species, as elicited by Everts,
are embodied in the preceding general account of the genus Vorticella, illustrated
by Figs. 32-47 of PI. XXXV.

Everts' interpretation of the minute histology of the contractile footstalk of
Vorticella nebulifera is illustrated by the figures from his drawings reproduced in
Figs, i and 2 of the accompanying woodcut. According to this investigator, the
central muscle-like cord exhibits, under the moderately high magnification of 600
diameters (Fig. i) the aspect of being finely and evenly striate transversely, after the

FIGS, i and 3. Vorticella nebulifera, Ehr. i. Contracted zooid with at s muscle-like element of the pedicle exhibiting
a transversely striated aspect, X 600 (after Everts). 2. Diagrammatic longitudinal section of lower half of the body ;
c, cuticle ; s, central muscle-like cord of pedicle continued at m into the myophan layer of the body-wall ; x, its
central cavity; r, cortical layer; i, central cavity of the body; «, nucleus or endoplast, X 1800 (after Everts).

FIG. 3. Carchesium polypinum, Lin. sp. Portion of stem as observed by the author ; a, external sheath or cuticle ;
b, central contractile cord, with c its granular sarcolemma-like investing membrane, which has become exposed and
twisted on itself through the fracture and shrinking of the central cord, X 2000.

manner of the striated muscular fibre of an ordinary metazoic organism. Under the
yet higher amplification of 1800 diameters (Fig. 2) each of these apparent transverse
striae, however, became resolved into parallel rows of minute longitudinal striae,

GENUS VORTICELLA. 675

having, as seen in optical section, ten to each row, divided by a hyaline central
space. The author has entirely failed to corroborate Everts' interpretation of this
structure, but has at the same time observed, in the case of Vorticella nebulifera,
V. campanula, and many other species, the presence of a more or less even layer of
granular corpuscles intervening between the hyaline outer sheath and the denser,
but apparently homogeneous central cord. A similar composition has been also
observed to obtain in the homologous structure of the compound type Carchesium
polypinum, of which indeed the author has succeeded in making preparations that
distinctly show the existence of these three elements, as indicated in Fig. 3 of the
accompanying woodcut. As there shown, this granular layer is distributed upon the
surface of a delicate hyaline membrane which encloses the central cord that both won-
derfully resembles, and physiologically corresponds with, the delicate external sheath
or " sarcolemma " of ordinary muscular tissues.

Vorticella picta, Ehr. PL. XLIX. FIG. 2.

Body conical-campanulate, about twice as long as broad, frontal
margin widest, slightly everted, parenchyma transparent ; cuticular surface
smooth ; pedicle slender, four or five times the length of the body, enclosing
an even linear series of minute scarlet corpuscles. Length i-i 1 50" to 1-570".
Inhabiting fresh water, social.

This species was obtained by Ehrenberg, growing abundantly on Salvinia natans,
at Pickelsburg, in the neighbourhood of Spandau on the Spree, in the year 1831,
but does not appear to have fallen beneath the observation of any subsequent
investigator. The peculiar character of the pedicle affords a ready clue to its future
identification.

Vorticella gracilis, Duj. PL. XLIX. FIG. 3.

Body evenly conical, about twice as long as broad, the anterior margin
widest, slightly everted ; parenchyma transparent ; cuticular surface smooth.
Length 1-520". HAB. — Marsh water, after long keeping.

No description of this species is given by Dujardin, but simply an illustration of
the body and a small portion of the pedicle of a single zooid, with a notification
of its habitat, as above.

Vorticella brevistyla, D'Udekem.
PL. XXXIV. FIGS. 13 AND 14, AND PLATE XLIX. FIG. 4.

Body ovate, nearly twice as long as broad, tapering posteriorly when
extended, spheroidal with a small anterior nipple-like projection when
contracted ; peristomal border rather narrower than the centre of the body,
not everted ; pedicle about half the length of the extended body, decumbent,
and forming half a spiral turn only when contracted. Length 1-300".

HAB. — Pond water.

This species, as described by D'Udekem * and obtained from pond water near
Brussels, closely resembles, with reference to the shortness of the pedicle, the forms
already described under the titles of Pyxidium and Rhabdostyla. The encystments
of the animalcule, as observed by D'Udekem, are of a brownish hue, subspherical,
with numerous angular asperities.

* ' Infusoires de la Belgique,' 1864.

P 2

676 ORDER PERITRICHA.

Vorticella dubia, From. PL. XLIX. FIG. 5.

Body smooth, campanulate, one and a half times as long as broad, the
anterior margin scarcely everted, exhibiting no distinct peristomal border ;
pedicle thick, not twice the length of the body. Length 1-640".

HAB. — Fresh water.

The description of this species is very imperfect, but if the figure given by
De Fromentel is to be relied on, a permanent feature for diagnosis is supplied by
the character of the anterior or oral margin of the animalcule, the peristome alto-
gether wanting that raised band-like contour characteristic of almost all other species
of the genus. As a consequence of this peculiarity, the anterior border presents
an undulating and uneven edge that contrasts strongly with the smooth and sharply
denned margin usually associated with this region.

Vorticella alba, From. PL. XXXIV. FIG. 33, AND PL. XLIX. FIG. 6.

Body in extension symmetrically ovate or turbinate, one and a half to
twice as long as wide, truncate anteriorly ; pyriform when contracted ;
peristome-border slightly constricted ; parenchyma very transparent ; cuti-
cular surface smooth, finely granulate or punctate ; contractile vesicle con-
spicuous; pedicle three or four times the length of the body. Length
1-400". HAB. — Fresh water, social.

A species evidently agreeing with De Fromentel's type, as above characterized,
has been recently obtained by the author in some abundance and in company
with Vorticella hamata, attached to Chara and ConferuacecB obtained from an
aquarium of some years' standing, in the Biological Laboratory, South Kensington.
The exceedingly neat and symmetrical contour of the body, together with the trans-
parency of the parenchyma, serves to distinguish this species readily from the
numerous other forms comprehended in this generic group. In one or two
examples, as indicated in the zooid to the left-hand side of the group here figured,
it was observed that a more or less conspicuously developed annular line or plication
divided the narrower posterior third from the two wider anterior thirds of the body,
while the cuticular surface under high magnification exhibited in all instances fine
longitudinally disposed granulations.

Vorticella fluviatilis, From. PL. XLIX. FIG. 7.

Body ovate, smooth, one and a half times as long as broad, truncate
anteriorly, having an indentation or depression at the posterior end or point
of insertion of the pedicle ; peristome-border narrow, scarcely everted ;
cuticular surface smooth ; oral fossa relatively large ; pedicle three or four
times longer than the body. Length 1-640". HAB. — Fresh water.

Vorticella crassicaulis, S. K.
PL. XXXIV. FIGS. 25 AND 26, AND PL. XLIX. FIG. 8.

Body when extended ovate or subfusiform, widest centrally, tapering
towards each extremity, but more so posteriorly, about twice as long as
broad, pyriform, with a snout or nipple-like anterior projection when con-
tracted ; peristome-border truncate, constricted and not everted ; pedicle
equal to or but slightly exceeding the body in length, very thick at its

GENUS VORTICELLA. 677

point of junction with the body, gradually tapering from thence towards
its proximal extremity, its external surface conspicuously wrinkled, the
central muscular fibrilla produced only through the distal moiety of its
total length, simply flexed and not coiled spirally when retracted ;
cuticular surface smooth ; parenchyma transparent ; endoplast elongate,
band-like. Length 1-600".

HAB. — Pond water, on Asellus aquaticus, social.

This minute species was obtained by the author attached in small colonies to
the above-named crustacean taken from a pond near Ashby-de-la-Zouch, Leicester-
shire, in January 1880. A like deportment of the pedicle during contraction — as
manifested by its simple flexure in place of spiral convolution — is shared by the
Vorticella brevistyla of D'Udekem, already described, while a similar development
of the central muscle-like cord within the distal moiety only of this structure
frequently recurs in V. spectabilis.

Vorticella cucullus, From. PL. XLIX. FIG. 9.

Body elongate-conical, attenuate, nearly three times as long as broad,
widest and slightly everted anteriorly, tapering gradually towards the
posterior extremity, the ciliary disc raised cushion-wise above the border
of the peristome; surface smooth; pedicle slender, relative proportions
unrecorded. Length of body 1-265". HAB. — Fresh water.

Vorticella longifilum, S. K.
PL. XXXIV. FIG. 30, AND PL. XLIX. FIG. 10.

Body conical, attenuate, about twice as long as broad, surface smooth ;
peristome slightly dilated ; pedicle exceedingly long and slender, contract-
ing spirally, ten or twelve times as long as the body. Length of body
1-370". HAB.— Fresh water, solitary.

This species in some respects resembles the Vorticella cucullus of De Fromentel
last described, but the body is less attenuate, while the pedicle — excepting only the
form mentioned below — exceeds in length and tenuity that of any species previously
described. The few specimens observed were obtained in October 1872, in pond
water containing Myriophyllum and other water-plants, from the neighbourhood of
Stoke Newington, London. An Egyptian species closely allied to and possibly
identical with this type, distinguished by the possession of an equally attenuate
pedicle, is described and figured by Schmarda,* under the title of Vorticella macro-
styla. The body is, however, apparently evenly ovate, and the peristome-border
contracted, but the figure given is on too small a scale for an exact apprehension
of its more minute specific characteristics.

Vorticella telescopica, S. K.
PL. XXXIV. FIGS. 31 AND 32, AND PL. XLIX. FIG. n.

Body conical or elongate-pyriform, tapering towards the posterior
extremity, a little over twice as long as broad ; cuticular surface smooth,
interrupted posteriorly by two transverse sulci, behind each of which it
becomes successively abruptly narrower ; when contracted the wider portions

* ' Denkschrift der Kaiser. Akacl. der Wiss. Wien,' 1854.

6; 8 ORDER PERITRICHA.

of the body in advance of each of these sulci overlapping the preceding
one after the manner of a telescope ; pedicle slender, scarcely exceeding
the body in length, contracting spirally. Length of body 1-500".
HAB. — Fresh water, solitary.

Obtained sparingly from pond water, in October 1872, in company with Vorticclla
longifilum.

** Bodies broadly campamilate.

Vorticella campanula, Ehr.
PL. XXXIV. FIG. 36, AND PL. XLIX. FIG. 12.

Body usually broadly campanulate or hemispherical, but soft and
very variable in contour ; subspheroidal, with a puckered anterior margin
when contracted ; the frontal margin widely dilated, often exceeding in
width the length of the body; the ciliary wreath apparently forming two
or more spiral convolutions ; pedicle thick, varying from three or four to six
or seven times the length of the body ; cuticular surface smooth, highly
elastic; parenchyma densely granular centrally. Length of body 1—250"
to i— 120". HAB. — Pond water, social.

The zooids of this species are clearly visible to the unaided eye, and often
occur in such abundance as to conspicuously cover the surface of submerged leaves
or other objects in the form of a thick bluish-white slime. A characteristic by
which, as pointed out by D'Udekem, this type may be easily recognized, is fur-
nished by the densely granular consistence of the internal parenchyma, which im-
parts to the central region of the body, when viewed with transmitted light, a black
and opaque aspect. It would seem probable, as anticipated by Ehrenberg, that the
Vorticella lunaris of O. F. Miiller, PI. XLIX. Fig. 42, is identical with this species.

In none of the numerous examples examined by the present author has the
larger size, quoted from Ehrenberg in the foregoing diagnosis, been encountered,
that of 1-250" to 1-200" being most dominant, and such dimensions being
considerably inferior to those of V. spedabilis, described later on.

Vorticella citrina, Ehr. PL. XXXV. FIG. 29, AND PL. XLIX. FIG. 13.

Animalcules broadly campanulate, hemispherical, plastic and changeable
in form, the frontal border much dilated, crateriform, often considerably
exceeding in diameter the entire length of the body; depressed with a
puckered anterior border when contracted; parenchyma transparent,
usually pale yellow ; cuticular surface smooth ; pedicle slender, four or five
times longer than the body. Length 1-430" to 216".

HAB. — Fresh water, on Lemna and various aquatic plants, social.

This species represents one of the most abundant fresh-water types. In the
plasticity of. the parenchyma and capacity to assume a great variety of contours, it
rivals the form last described, while in the patellate or crateriform expansion of the
peristome-border it more nearly approaches Vorticella hemisphcerica and V. patellina.
In its contracted state the body of this animalcule, as observed by the author,
exhibits a very characteristic contour; the anterior margin in all these instances
assuming a more or less lobate or puckered aspect, while the body as a whole some-
times retains a subspheroidal form, but more often presents a much depressed melon-
or tomato-like outline. Under a magnification of three or four hundred diameters,

GENUS VORTICELLA. 679

the cuticular surface was shown, by a careful adjustment of the light, to be very
finely striate transversely, this ornamentation being more especially apparent in
specimens whose life was nearly extinct. These striations not being visible under
ordinary conditions, this type has been retained among the smooth-surfaced series.

Vorticella cratera, S. K. PL. XXXIV. FIG. 22, AND PL. XLIX.- FIG. 14.

Body broadly campanulate, inflated and hemispherical, the breadth
often two or three times greater than the total length; peristome-border
flattened and expanded, crateriform, often revolute ; ciliary disc but slightly
elevated ; parenchyma white, cuticular surface smooth ; pedicle stout, five
to seven or eight times the length of the body, contracting spirally.
Length -i -480". HAB. — Fresh water, social.

The above specific title is here proposed for the reception of the so-called Vorti-
cella patcllina of Ehrenberg, but which is entirely distinct from the essentially marine
animalcule upon which the same name was originally conferred by O. F. Miiller.
This latter form has been recently met with by the author, and is described in the
next paragraph. D'Udekem gives a highly characteristic drawing of the present
species in his ' Infusoires de Belgique,' as here reproduced, in which for the first
time full justice is done to the exceedingly elegant frill-like aspect presented by the
peristome-border in its typical expanded state.

Vorticella patellina, Mull.
PL. XXXV. FIG. 26, AND PL. XLIX. FIG. 15.

Body conical-campanulate in extension, widest at the anterior border,
and tapering thence in a straight line to its point of junction with the
pedicle ; pyriform with a puckered anterior margin when contracted ; the
diameter of the expanded frontal border equalling or but slightly less than
the total length of the body ; the peristome-edge exceedingly thin, expand-
ing in a flattened or rotate form around the frontal margin ; ciliary disc
but slightly elevated ; parenchyma transparent ; cuticular surface smooth ;
pedicle slender, three or four times the length of the body, contracting
spirally. Length 1-350". HAB. — Salt water, social.

The animalcule corresponding with the foregoing diagnosis was obtained by the
author, attached to algae and zoophytes, at Guernsey, in September 1871, and
evidently represents the true marine Vorticella patellina, as originally named and
figured by O. F. Miiller,* with which Ehrenberg and subsequent writers have pro-
posed to correlate the fresh-water type last described. The exceedingly straight
lateral walls, and consequently angular aspect of the bodies of this species, as pre-
sented during their most characteristic expanded state, distinguish it conspicuously
from all other representatives of the genus ; this lateral outline, joined to that of the
equally straight frontal border, communicates in fact to the animalcules, as seen
in optic section, the contour of an almost perfect equilateral triangle.

Vorticella nutans, Mull.
PL. XXXIV. FIG. 28, AND PL. XLIX. FIG. 16.

Body broadly campanulate in extension, nearly as wide as long, pyri-
form or globose when contracted, soft and elastic, cuticular surface smooth ;

* ' Zoologia Danica,' 1776.

680 ORDER PERITRICHA.

the peristome-border dilated, but not crateriform or greatly revolute, a
deep notch or constriction usually separating it from the remainder of the
body ; oral fossa large, pharynx deeply prolonged ; the posterior extremity
of the body, immediately preceding its junction with the pedicle, conical
and attenuate ; pedicle transparent, slender, three or four times longer than
the body, mostly assuming in connection with this structure a more or less
inclined position ; parenchyma transparent or pale yellow, finely granulate.
Length 1-430" to 1-300". HAB. — Fresh water, social.

This species, originally described by O. F. Miiller, and since lost sight of, has
been re-discovered by De Fromentel, and has more recently, February 1879, been
met with in some abundance by the author in the neighbourhood of St. Heliers,
Jersey. The distinctive feature by which it may be readily identified, is afforded by
the gracefully inclined or pendulous position almost invariably assumed by the broad
campanulate body with reference to its supporting pedicle. The pedicle itself,
again, when the zooid is fully expanded, frequently remains curved, and on con-
traction assumes a more or less loose and imperfect spiral coil. The substance of
the body and overlying cuticle is soft and plastic, permitting of a considerable
puckering of the contour of the periphery, but this to a much less degree than is
observable in either Vorticella campanula or V. citrina.

The majority of the examples examined exhibited a pale yellowish hue, and were
found both solitary and forming small scattered colonies, attached to Conferva taken
from a roadside ditch, containing much decaying vegetable matter, running during
the winter months, but habitually dry in summer. These specimens were found to
live for a long while in the close confinement of a small glass vessel. In his list of
synonyms, De Fromentel has proposed to identify this type with the Vorticella
infusionum of Dujardin, a species, however, with which it certainly cannot be said to
exhibit a single point in common. The marine Vorticella gemella of O. F. Miiller
would appear to be a type closely corresponding with the present type, if not
indeed a merely salt-water variety of it. In many cases the presence of two zooids
upon one stalk, resulting from longitudinal fission, was noted by that early- inves-
tigator, and being interpreted by him as the normal expression of the species,
suggested the title given.

Vorticella aperta, From. PL. XLIX. FIG. 17.

Body conical-campanulate, or pyriform, one and a quarter times longer
than wide, tapering posteriorly, slightly constricted beneath the peristome ;
surface smooth and transparent ; the substance of the inner layer of the
body contracted at its junction with the pedicle, and presenting the appear-
ance of a supplementary thick bounding membrane or cortical layer around
this point ; pedicle stout, about three times longer than the body. Length
1-400". HAB. — Fresh water.

Vorticella procumbens, From. PL. XLIX. FIG. 18.

Animalcules exceedingly transparent, campanulate, scarcely longer than
broad ; peristome everted ; pharyngeal cleft much prolonged ; pedicle
decumbent, three or four times longer than the body. Length 1-530".

HAB. — Fresh water.

The most important character of this species, as described by De Fromentel, is
the procumbent position always assumed by the pedicle when in a state of full
extension.

GENUS VORTICELLA. 68 1

Vorticella dilatata, From. PL. XLIX. FIG. 19.

Body broadly campanulate, truncate and widely expanded anteriorly,
its breadth equalling the total length, no constriction behind the
peristome-border, the posterior extremity narrowly truncate; oral fossa
large ; pharyngeal cleft produced almost through the length of the body ;
ciliate throughout, vestibular seta conspicuous ; pedicle short, compara-
tively slender; parenchyma white, granular; cuticular surface smooth.
Length 1-350". HAB. — Fresh water.

Although of small size, this species would seem, from De Fromentel's illustration
and brief description, to correspond closely with one of the many aspects assumed
by Vorticella campanula. As in the case of so many other forms described by him
as new, no details, however, are given of the comparative length of the pedicle, of
its social or solitary habits, or other data that would assist in its future identification.

Vorticella fasciculata, Mull. PL. XLIX. FIG. 20.

Body broadly campanulate, the anterior margin reflected ; pedicle from
three to five or six times the length of the body.

HAB. — Pond water, on Conferva ; colour green ; social.

This species, according to Miiller, forms green gelatinous masses upon aquatic
plants, not only distinctly visible to the unassisted vision, but of considerable extent.
The broadly campanulate contour of the body, as indicated in the original figures
and description given by M filler, preclude its identification with Vorticella chloro-
stigma as suggested by Ehrenberg. The parenchyma would appear to be very clear
and homogeneous, as in V. citrina, which species, indeed, except for its dark olive-
green colour, it would seem to much more nearly resemble. De Fromentel figures as
representing this form an animalcule whose body is entirely colourless and mounted
on a pedicle of much greater relative length. He makes no reference to the
essentially gregarious habits which so prominently distinguish Miiller's type.

Vorticella coxnmunis, From. PL. XLIX. FIG. 21.

Body even, conically campanulate, the length equalling or slightly
exceeding the greatest breadth ; peristome-border everted ; ciliary disc but
little elevated ; parenchyma transparent ; cuticular surface smooth ; pedicle
stout, about four times longer than the body. Length 1-800".

HAB. — Fresh water.

This minute type is represented by De Fromentel as a very abundant fresh-water
form, whose identity with any of the species of the older writers cannot be satisfac-
torily established.

*** Bodies spheroidal.
Vorticella globularia, Mull. PL. XLIX. FIG. 22.

Body spherical ; peristome small, contracted, and not everted ; pedicle
slender, six or seven times longer than the body, retracting spirally.
Dimensions unrecorded.

HAB. — Fresh water, social, attached to a species of Cyclops.

682 ORDER PERITRICHA.

This species, as figured and described by O. F. Miiller,* possesses a just claim
for recognition in this treatise, no spheroidal type with a pedicle of so great a
relative length having up to the present time been recorded by any more recent
investigator. So far as it is possible to judge, comparing Miiller' s drawings with
the figures given by him of other well-known species, the diameter of the body of
this animalcule is about 1-150". Its habitat being so clearly defined, its rediscovery
may be anticipated.

Vorticella sphserica, D'Udek. PL. XLIX. FIG. 23.

Body spherical, nearly as broad as long, its surface smooth ; pedicle
short, about twice the length of the body, comparatively thick ; peristome-
border and ciliary disc small and contracted, the latter structure but
slightly elevated. Length 1-820". HAB. — Fresh water.

This species was obtained by D'Udekem from the Willebroeck Canal, near
Brussels. No allusion is made in his description to either its solitary or social
habits.

Vorticella margaritifera, From. PL. XLIX. FIG. 24.

Body spherical, hyaline, granulate, enclosing brilliant refringent cor-
puscles ; ciliary wreath very minute, vestibular fossa large ; pharyngeal cleft
deeply prolonged, conspicuously ciliate ; pedicle short and stout, twice the
length of the body, its attached or proximal extremity conspicuously dis-
coidal. Length 1-400". HAB.— Fresh water.

De Fromentel \ remarks of this species that it can close its ciliary disc without
contracting its pedicle ; as also, that the pedicle does not retract in a spiral form but
is simply shortened by the closer apposition of its annular rings, its external trans-
parent sheath becoming at the same time transversely wrinkled. The body in
general form, while of smaller 'size, corresponds closely with the species last
described.

Vorticella mamillata, From. PL. XLIX. FIG. 25.

Body almost spherical, smooth and transparent, slightly granular ; peri-
stome narrow, projecting when expanded in the form of three nipple-like
papillae ; pedicle moderately thick, two or three times longer than the body.
Length 1-750". HAB. — Fresh water.

Vorticella constricta, From. PL. XLIX. FIG. 26.

Body subspheroidal, smooth, granular, slightly flattened ; peristome-
border very narrow, taking the form of two raised papillae surmounted by
prominent vibratile cilia ; oral fossa situated between these papillae, followed
by a short pharyngeal cleft; the posterior extremity exhibiting at its junc-
tion with the pedicle a short conical prolongation ; pedicle slender, about
twice the length of body, contracting in a zigzag and not in a spiral manner.
Length 1-530". HAB. — Fresh water.

This species appears to be closely allied to the Vorticella mamillata of the same
author, last described. The papilliform prominences in either case possibly represent
an abnormal condition only of the peristome and ciliary disc.

1 Animalcula Infusoria,' p. 313, tab. xliv. fig. 14. f 'Etudes sur les Microzoaires,' 1876.

GENUS VORTICELLA. 683

/

B.— CUTICLE DISTINCTLY STRIATE OR OTHERWISE ORNAMENTED.

* Bodies conical or elongate.

Vorticella microstoma, Ehr.
PL. XXXV. FIGS. 9-24, AND PL. XLIX. FIG. 27.

Body somewhat variable in form, usually ovate or subpyriform, about
one and a half times as long as broad, but sometimes almost spheroidal ;
cuticular surface finely striate transversely ; peristome-border very narrow
and constricted, not everted, about one-half of the width of the centre
of the body ; pharyngeal cleft greatly prolonged ; pedicle varying from
two or three to five or six times the length of the body, usually inserted
into a narrower conical posterior prolongation of the body proper. Length
1-750'' to 1-240".

HAB. — Stagnant water and infusions ; solitary or in social clusters.

This species represents one of the most widely distributed members of the genus ;
it occurs in almost all water containing decaying vegetable matter, and may be
abundantly developed, in company with V. putrinum, from artificial hay-infusions.
Under the last-named conditions it usually makes its appearance so early as from
a week to ten days after placing the hay to macerate, while the characteristic
encystments that give rise to the active animalcules may be detected imbedded in
the substance of the hay within a few hours of its first immersion. The species
multiplies very rapidly by longitudinal fission, the few first released from the primary
cysts soon producing extensive colonies by the constant repetition of this process.
Prior to its separation from the parent, a girdle of cilia is produced round the pos-
terior extremity of the migrant zooid, which, as it hangs from the parent stalk,
presents the aspect of an independent gemmule. It not unfrequently happens
that while thus pendent this zooid again subdivides into two of less magnitude,
while D'Udekem records and figures one example, see PI. XXXV. Fig. 19, in
which, while yet attached, the migrant animalcule split up into as many as eight
minute pyriform zooids, which were presently scattered into the surrounding water.
It would seem probable that these rarely produced, more minute zooids represent
those whose mission it is to coalesce with the typical sedentary forms, and secure
in a sexual generative manner the further multiplication or rejuvenescence of the
parent stock, those formed by the simple subequal division of the parent zooid, as
a rule, reaffixing themselves, and soon, by the growth of a new pedicle, becoming
indistinguishable from the latter. Fuller details of the reproductive phenomena of
this species are recorded in the general description of the genus given in a previous
page. The striations of the cuticular surface of Vorticella microstoma are clearly
visible only in association with a careful manipulation of the light, and indeed this
surface is represented by many authorities as perfectly smooth and transparent. Both
Ehrenberg, and Stein in his earlier writings, figure with this type minute stalked
animalcules having a length of less than 1-2000", and which are described as its
young. There can be but little doubt, however, that these minute stalked organ-
isms are independent flagellate forms, such as Spumella or Oikomonas, which are
abundantly developed in the water that contains this species. On the other hand,
the author has never as yet met with examples attaining the largest size given by
Ehrenberg, viz. 1-240", the majority of examples observed varying in length from
1-750" to 1-600". In infusions containing an abundance of this form the author
has frequently met with zooids detached from their pedicles, having no posterior
ciliary wreath, but swimming with the aid of their peristomal cilia only, and presenting
an inflated subglobose contour, as shown at PI. XXXV. Fig. 17. These detached
zooids were subsequently found to develope into the ovate encystments, with a

684 ORDER PERITRICHA.

crenated border, as delineated in the succeeding figure. The Vorticella plicata and
V. striata of De Fromentel, admitted by that authority to be probably varieties of
the same species, seem to be referable to the present type ; the transverse
stria; are apparently coarser and more pronounced, and in this respect more closely
coincide with those of the marine Vorticella striata of Dujardin. By the last-named
investigator the animalcule now under discussion is figured and described under the
title of Vorticella infusionum ; the cuticular striations are, however, misrepresented
as taking an oblique direction.

Vorticella putrinum, Mull.
PL. XXXIV. FIGS. 23 AND 24, AND PL. XLIX. FIG. 28.

Body elongate, subfusiform, widest centrally and tapering towards each
extremity, the posterior region being most attenuate, from two to three
times as long as broad ; ovate, with a nipple-like anterior projection, when
contracted ; peristome-border constricted, scarcely everted ; the cuticular
surface finely striate transversely ; pedicle three or four times as long as
the body. Length 1-430" to 1-300".

HAB.— Vegetable infusions in both salt and fresh water.

The species, as above characterized, has been obtained abundantly by the
author in hay-infusions in both salt and fresh water, and is undoubtedly identical
with the form first associated with the foregoing title by O. F. Miiller, and figured by
him in his ' Zoologiae Danicae Prodromus,' in the year 1776. From Vorticella micro-
stoma, of which in fresh-water infusions it is a frequent companion, it may be readily
distinguished by the much more elongate contour of the body. An example in
which two smaller migrant zooids are being produced through a repetition of the
ordinary fissive act of a normal animalcule, is depicted at PI. XXXV. Fig. 230.

Vorticella striata, Duj.
PL. XXXIV. FIGS. 15-19, AND PL. XLIX. FIG. 29.

Body ovate or pyriform, about one and a half times as long as broad,
widest centrally, conically pointed posteriorly, constricted towards the border
of the peristome, which is narrow, not dilated, and measures one-half the
width of the centre of the body, the ciliary disc slightly prominent ; cuti-
cular surface conspicuously striate transversely ; pedicle slender, about
twice the length of the body. Length 1-850" to 1-600".

HAB. — Salt water ; solitary or in scattered groups.

This species, like Vorticella grarilis, is figured but not described by Dujardin,
an appended note indicating only its size and salt-water habitat. The present
author has recently, January 1879, obtained an animalcule corresponding with
Dujardin's type in all essential points, on the Jersey coast, finding it attached to
zoophytes and seaweeds freshly dredged from a depth of ten fathoms, off St. Aubin's
Bay. In size and general contour it very nearly resembles the V. microstoma of
stagnant pond water and infusions, but the transverse striae are coarser and more
conspicuous, and the body is much more retentive of its typical pyriform or urn-
like shape. Multiplication by longitudinal fission, and the reattachment of the
migrant zooid, as in the last-named form, was observed, the latter at the time
of, and anterior to, its separation from the parent stalk, assuming, as shown at
PI. XXXIV. Fig. 1 6, a somewhat eccentric contour, the conical posterior extremity
being as it were invaginated, or thrust into the central body-portion. In one
example carefully followed, the migrant zooid occupied half an hour in wandering

GENUS VORTICELLA. 685

about and selecting a site for the initiation of its independent sedentary life, another
hour elapsing between this and its development of a pedicle and the disappearance
and absorption of the posterior circlet of locomotive cilia. During its nomadic
existence the animalcule expended a considerable interval in creeping, after the
manner of a Trichodina, over the surface of the glass slide and algoid filaments
with the aid of its flattened posterior extremity and associated wreath of cilia, and
which for the nonce fulfilled all the essential purposes of the complex acetabuliform
organ of the last-named genus. The species figured by Mereschkowsky in his
' Protozoa of Northern Russia,* under the name of Vorticella pyrum, must be
regarded as a local variety only of the present type. The examples there figured,
as found attached to algae and hydroid zoophytes in the White Sea, differ from the
present form merely in the greater relative length of the pedicle, which equals three
or four times that of the body ; the contour of the body, together with its charac-
teristic striation, is otherwise essentially identical.

Vorticella marina, Greeff.
PL. XXXV. FIGS. 1-8, AND PL. XLIX. FIG. 30.

Body conical, campanulate, tapering posteriorly, slightly constricted
beneath the peristome, about one and a half times as long as broad ;
peristome-border thick, dilated and revolute, ciliary disc moderately
elevated ; cuticular surface distinctly and coarsely striate transversely ;
pedicle somewhat thick, four or five times the length of the body, con-
tracting spirally. Length 1-375".

HAB. — Salt water, scattered or in small social groups.

This species, described by Greeff,t has been obtained by the author both at
Bognor, Sussex, in August 1872, and also attached to the algae and zoophytes on the
Jersey coast. From the Vorticella striata of Dujardin, which it to some extent re-
sembles, it may be distinguished by the considerably more dilated and revolute
character of the peristome-border. The conjugation of the more minute migrant
zooids with the sedentary individuals forms the especial subject of Greeff 's account
of the species, and has been referred to in detail in the general account given on
a preceding page of the reproductive phenomena of the genus Vorticella.

Vorticella quadrangularis, S. K.
PL. XXXIV. FIG. 34, AND PL. XLIX. FIG. 31.

Body attenuate, subcylindrical, three and a half time* as long as broad,
tapering posteriorly, with a projecting angle at within a short distance of
both the anterior and posterior extremities, faintly striate transversely,
slightly constricted beneath the peristome, ciliary disc projecting hemi-
spherically above the border of the peristome ; pedicle slender, compara-
tively short, about one and a half times longer than the body. Length of
body 1-125". HAB. — Pond water ; social.

In proportion to its width, the present species represents the most attenuate
representative of the genus yet recorded. The specimens from which the accom-
panying figures and description are derived were found growing on Myriophyllum
in pond water derived from the neighbourhood of Stoke Newington, London, in
September 1871. ^__

* 'Archiv fur Mikroskopische Anatomic,' Dec. 1878.
t Wiegmann's ' Archiv fur Naturgeschichte," 1871.

686 ORDER PERITRICHA.

Vorticella elongata, From.
PL. XXXV. FIG. 25 (?) and PL. XLIX. FIG. 32.

Body subcylindrical or elongate-conical, from two to three times as long
as broad ; the posterior extremity conically pointed ; the anterior margin
slightly expanded ; peristome forming a conspicuously raised border round
the somewhat elevated dome-like ciliary disc ; cuticular surface trans-
versely striate ; pedicle stout, its relative length unrecorded, contracting
spirally or in folds. Length 1-400". HAB. — Fresh water.

An animalcule has been recently obtained by the author from pond water in
the neighbourhood of St. Heliers, Jersey, that would appear to correspond with
the Vorticella elongata of De Fromentel, but it is of somewhat larger size, varying
from 1-300" to 1-250". Its habits are solitary, a few only, scattered at distant
intervals, being found on each small fragment of Conferva examined. The pedicle
was slender, and four or five times longer than the attenuately-conical and con-
spicuously striated body. Its internal muscular cord presented, in all instances,
as shown at PI. XXXV. Fig. 25, a finely granulate aspect, closely resembling,
except for the absence of colour, that attributed by Ehrenberg to Vorticella picta.
De Fromentel figures and describes a second animalcule under the title of Vorti-
cella multangula which agrees so closely with V. elongata that the author cannot
regard the two as otherwise than identical. This second species is associated by
him with the title given in reference to the apparent zigzag course described by the
muscular fibrilla within the pedicle, a*id which he reports as having been observed
by him in but one other species, his V. margaritata. Such a disposition of the
muscular fibre, correctly spiral, is common, however, to all the members of the
genus, and is actually delineated by him in the majority of the species he describes,
including even the present form.

Vorticella chlorostigma, Ehr. PL. XLIX. FIG. 33.

Body conical-campanulate, about twice as long as broad, the frontal
margin considerably dilated ; parenchyma green, densely granular ; cuti-
cular surface transversely annulate ; pedicle thick, four or five times longer
than the body. Length 1-240". HAB. — Fresh water ; social.

This species, excepting for its bright coloration, would appear to agree entirely
in shape, size, and cuticular striation with Vorticella convallaria ; it is reported by
Ehrenberg as occurring abundantly in the neighbourhood of Berlin, where it is often
found covering the stem of grasses and other submerged objects so densely as to
present to the unassisted eye the appearance of bright green slime, resembling that
formed by the still larger green Trumpet-animalcule, Stentor viridis. The Vorticella
fasciculata of O. F. Miiller is referred to by Ehrenberg as being possibly identical
with this species. It forms similar dense green masses upon the surface of
aquatic plants, but the separate zooids would appear to possess a shorter, broadly
campanulate contour, which more closely corresponds with that of V. citrina.

Vorticella convallaria, Linn. PL. XLIX. FIG. 34.

Body conical-campanulate, about twice as long as broad, the frontal
region dilated, slightly revolute ; parenchyma whitish or hyaline ; cuticular
surface transversely annulate ; pedicle rather thick, from three to six times
the length of the body. HAB. — Stagnant water and infusions ; social.

As previously mentioned, this species represents one of the first discovered
infusorial forms, it being identical with the so-called "animalcules of the first size"

GENUS VORTICELLA. 687

described by Leeuwenhoek in the ' Philosophical Transactions,' London, 1675,
which subsequently (ib. 1703) received from him the more distinctive title of Bell-like
animals. Linnaeus, in his ' Systema Naturae,' 1758, embodies the same species under
the name of Hydra eonvallaria, conferring upon it its generic title of Vorticella in
ed. xii. of the same work published in the year 1767. By some authorities this
species has been supposed to be synonymous with Ehrenberg's Vorticella microstomum.
The dilated form of the frontal border in the present instance, however, as com-
pared with the constricted contour of this region in the last-named species, precludes
the serious entertainment of such a proposed identification.

Vorticella hamata, Ehr.
PL. XXXIV. FIG. 27, AND PL. XLIX. FIG. 35.

Body elongate-conical, somewhat gibbous, about twice as long as broad,
constricted beneath the peristome-border and tapering towards the posterior
extremity, obliquely set upon its pedicle, evenly and elongate pyriform
when contracted ; cuticular surface finely striate transversely ; pedicle
short, rarely exceeding twice the length of the body, usually less. Length
1-600". HAD. — Fresh water ; solitary or in small social groups.

This species, as figured and briefly described by Ehrenberg, would appear to
accord more nearly with the Vorticella inclinans of O. F. Miiller than the so-called
V. hamata of that authority, which is apparently a free-swimming type allied to Strom-
bidium. A form entirely agreeing with the Ehrenbergian species, as here figured and
characterized in the foregoing diagnosis, has been met with on various occasions
by the present author, and notably in company with Vorticella alba attached to
Chara and confervoid growths obtained from an aquarium of some years' stand-
ing in the South Kensington Biological Laboratory, during the months of January
and February 1880. The contour of this animalcule, with its rigidly extended
pedicle and obliquely set, gibbously ovate body, corresponds in a remarkable manner
with the spore-receptacle, theca or sporangium, of a Hypnum or other moss form.

Vorticella spectabilis, S. K.
PL. XXXIV. FIG. 35, AND PL. XLIX. FIG. 36.

Body plastic and somewhat variable in form, elongate-conical, widest
anteriorly, tapering posteriorly, nearly three times as long as broad when
fully extended, subspheroidal in its contracted state ; the peristome dilated
and widely everted ; cuticular surface finely striate transversely ; parenchyma
coarsely granulate, lightish brown ; pedicle short and stout, rarely exceeding
two or three times the length of the body, more usually of the same length
or even shorter. Length 1-150". HAB. — Pond water ; social.

This species has been obtained by the author on one occasion only, being
then found, in June 1879, attached in social clusters to the leaves of duckweed,
Lemna minor, taken from a roadside pond near Ashby-de-la-Zouch. While most
closely approaching Vorticella campanula in the large size of the individual zooids,
it is readily distinguished from that type by the more attenuate contour of the
body, by its simple spheroidal and unpuckered outline in the contracted state, and
by the very short comparative length of the pedicle. A distinctive character con-
nected with this last-named element, that is well shown in permanently preserved
examples, is afforded by the fact that in the majority of instances the central
muscle-like fibrilla is not developed throughout the length of the pedicle, but from
its junction with the animalcule's body to a point midway only between this and its

688 ORDER PERITRICHA.

basal extremity. It might be predicted that the compound stock-form Carchesium
has been developed from a simple Vorticellidan that exhibited a similar structural
peculiarity.

** Bodies broadly campanulate.

Vorticella microscopica, From. PL. XLIX. FIG. 37.

Body conical-campanulate, its surface striate; peristome-border everted,
constricted beneath, its diameter equalling the length of the body, vestibular
seta moderately developed ; pedicle slender, contracting spirally, five or six
times longer than the body. Length 1-2000". HAB. — Fresh water.

According to the description and figure given by De Frorrientel,* this species
closely resembles in shape his V. fasriculata, though the stem is shorter and thicker
in proportion, and the surface of the body is described as striate, though it is not so
figured in the accompanying illustration. The same writer hazards the opinion that
the species is possibly identical with the Vorticella picta of Ehrenberg, though upon
what grounds such an identity is premised it is difficult to conjecture.

Vorticella appuncta, From. PL. XLIX. FIG. 38.

Body broadly campanulate, widely everted anteriorly, nearly as wide
as long; the ciliary disc elevated obliquely in a tongue-shaped form
above the margin of the peristome ; cuticular surface finely striate trans-
versely ; pedicle rather thick, its relative length unrecorded, enclosing
numerous brilliant green corpuscles. Body when contracted globular,
invaginate around or overlapping the insertion of the pedicle. Length
1-420". HAB. — Fresh water.

The granular composition of the internal structure of the pedicle of this species
finds its analogue in the Vorticella picta of Ehrenberg and in the apparent variety of
V. elongata figured by the author at PI. XXXV. Fig. 25.

Vorticella monilata, Tatem.
PL. XXXV. FIG. 27, AND PL. XLIX. FIG. 39.

Body broadly campanulate, widest and everted anteriorly ; the peristome-
border thick, often revolute, its diameter when fully expanded equalling or
exceeding the length of the body ; subspheroidal when contracted ; pharyn-
geal cleft deeply prolonged ; parenchyma transparent, colourless ; the
entire cuticular surface ornamented with hemispherical bead-like elevations,
which are disposed in closely set annular series, those on the peristome-
border of the largest size ; pedicle stout, four or five times longer than the
body ; endoplast comparatively short, band-like. Length 1-400" to 1-350".

HAB. — Fresh water ; forming small social colonies.

This species was first discovered by Mr. J. G. Tatem, who figured and described
it under the above name in the ' Monthly Microscopical Journal ' for April 1870 as
a probable malformed or monstrous variety of Vorticella convallaria. Subsequently,
1876, De Fromentel has most imperfectly figured and described it in his ' Microzoaires,'
in connection with the newly proposed title of Vorticella margaritata. By neither of
these two writers, however, can full justice be said to have been done to the contour

Etudes sur les Microzoaires,' 1876.

GENUS VORTICELLA. 689

of the expanded body or to the ornamentation of the cuticular surface of this exceed-
ingly elegant form, although of the two Mr. Tatem's delineations are by far the more
characteristic and complete. According to this last-named authority, it is by no means
an uncommoji form, he having obtained it from various widely different localities.
The present author has also had the good fortune to meet with this very distinct type
on several occasions, receiving it first, in March 1874, growing upon Myriophyllum in
company with Epistylis grandis and other animalcules, through Mr. Thomas Bolton,
from the neighbourhood of Stourbridge, Worcestershire, and has more recently obtained
it in the neighbourhood of Ashby-de-la-Zouch. From the notes and sketches made
at these times, it is now found possible to fill up certain of the very extensive
lacunae left by its original describers. In the first place, the beading of the cuticular
surface has been demonstrated by examination with a high magnifying power to be
much more even, closely set, and generally distributed than is indicated by either
Mr. Tatem or De Fromentel. The symmetrically annular disposition of these bead-
like prominences, and their correspondence in that respect with the transverse
cuticular striae of various other species, is recognized by the former writer, but he has
at the same time represented the separate beads as much more distinctly isolated
from one another than is actually the case, while the elevated and in certain aspects
dome-like ciliary disc is, in accordance with Mr. Tatem's drawing, entirely smooth
and deficient in the ornamentation that distinguishes the remaining portion. The
surface of the ciliary disc was found by the author to be similarly decorated, the
hemispherical elevations being, indeed, of slightly larger size than on the walls of
the body. This cuticular ornamentation, however, attains its most conspicuous
development on the surface of the peristome-border, in which region the bead-like
markings are quite twice the size of those of the subjacent area. When expanded to
its full extent the peristome-border is everted and revolute to an extent apparently
unobserved by its previous biographers, the contour of the body also assuming at
such times a more elongate, conoidal outline. Between this conical shape and the
perfectly spheroidal one assumed in its contracted state, every gradational contour
may be exhibited. De Fromentel cites as a special character of this type the zig-
zag, or more correctly spiral, disposition of the contractile muscular cord within the
pedicle. This is, however, common to all Vorticelltz, but in this type, on account of
its large size, is particularly prominent. For a similar reason, the continuation of
this cord up the walls of the body as distinct fibrillae is also clearly shown in this
species. About six or eight zooids usually made up the colonies of this species as
examined by the author ; in most instances a conspicuous but comparatively short
band-like endoplast was observed.

Supplementary Species.

The following Miillerian species are too insufficiently defined for inclusion
among the preceding series, their original diagnoses being however here reproduced
with a view to their possible rediscovery and more exhaustive description.

Vorticella cyathina, Miiller, PI. XLIX. Fig. 40. — Body crateriform, stalk spirally
retractile. Hab. Salt water preserved in glass vessels.

The shape of the body of this species as figured by O. F. Miiller,* coincides
most nearly with that of Vorticella campanula or V. nutans. The average length of
the pedicle is from three to four times that of the body.

Vorticella annularis, Miiller. PI. XXXIX. Figs. 27 and 28. — Body elongate-
conical, the anterior margin truncate, the distal end of the footstalk alone retractile,
this region thickened and smooth when extended, annulate when contracted.
Hab. Fresh water, attached to Planorbis sp.

According to Miiller's figures and description of this species, the separate zooids
are of a very considerable size, being distinctly visible to the unaided eye, and
measuring in length the i~3oth or even the i-25th of an English inch. Excepting
for their large size and the fact that each zooid in the colony he delineates is

* ' Zoologia Danica,' 1788.
VOL. II.

690 ORDER PERITRICHA.

attached to an independent pedicle, this type might have been identified with the
immature condition of Epistylis plicatilis, with which it agrees both in habitat and in
the apparent annulate character of the posterior extremity of the body — identified by
Miiller with the pedicle — in its contracted state. Should this species be rediscovered,
it will probably be found desirable to refer it to the author's newly instituted genus,
Rhabdostyla.

Vorticella hians, Miiller, PI. XLIX. Fig. 41. — Body elongate, pyriform or
lemon-shaped, widest and inflated posteriorly, about twice as long as broad ; pedicle
very short, scarcely as long as the body. Hab. Long-standing vegetable infusions.

The above diagnosis and figure refer to what Miiller designates var. /? of Vorti-
cella hians, which is alone figured, and appears to be the most distinct form. In
more normal examples the pedicle equals three times the length of the body.

GENUS VIII. CARCHESIUM, Ehrenberg.

Animalcules ovate or pyriform, alike in shape and size, resembling those
of Vorticella, but united in social clusters, and forming compound dendritic
colony-stocks or zoodendria through repeated longitudinal fission, accom-
panied by the regular or irregular branching of their flexible primary
pedicle ; the muscular fibre within the compound pedicle not continuous
throughout, but interrupted at each bifurcation, so as to permit of the
independent extension and contraction of the separate zooids. The species
so far discovered mostly inhabit fresh water.

The compound colony-stocks of the genus Carchesium, in common with those of
the genera Zoothamnium, Epistylis, and Opercularia, may be said to represent the
sum total of the normal fissive process of an ordinary Vorticella, but in which the
entire number of zooids so produced have, in place of becoming separately dispersed,
remained permanently united by their respective pedicles. The non-continuity of
the central muscular fibrilla, which permits the associated animalcules to contract
separately or in limited numbers on their compound footstalk, serves to distinguish
this genus from its nearest ally Zoothamnium.

Carchesium polypinum, Lin. sp.
PL. XXXV. FIGS. 30, 31, AND 51, AND PL. XXXVI. FIGS. 1-8.

Bodies conical-campanulate, somewhat gibbous, the anterior or peri-
stomal border dilated, revolute ; parenchyma transparent, colourless ; cuti-
cular surface smooth ; compound pedicle or zoodendrium not articulate,
subumbellate, consisting usually of an erect main rachis, from the summit
of which subtend a greater or less number of horizontal or oblique, simple
or ramifying branchlets which support the pedicellate animalcules, these
more usually exhibiting a unilateral plan of disposition. Length of bodies
1-570" to 1-430".

HAB. — Mostly fresh, but sometimes salt water.

This species frequently occurs in ponds in such profusion as to form, as in
the case of Vorticella campanula and Epistylis grandis, a conspicuous, bluish-white,
mucilaginous film upon the surface of the water-plants or other objects to which
it may be attached. While among the commonest, it is undoubtedly one of
the most beautiful and luxuriantly growing representatives of the present family
group, the branching tree-like colonies, resulting from the multiple fission of a single
primary individual, often including as many as several hundred animalcules. Although

GENUS CARCHESIUM. 691

each separate zooid is able, through the isolation of the muscular fibre of its pedicle,
to contract independently of its fellows, it more usually happens that a whole branch,
or if much disturbed, the entire colony, as shown at PL XXXVI. Fig. 2, becomes
drawn together into a spheroidal mass, the basal portion or main stem in this case
assuming a spiral or closely adpressed zigzag contour. It is not to be wondered at
that so prominent and widely distributed a species as Carchesium polypinum attracted
the notice of the older investigators. It is included as one variety of the " Bell-
like animalcule " described by Leeuwenhoek in the ' Philosophical Transactions ' for
1703, and receives the respective names of Sertularia polypina and Vorticdla polypina
from Linnaeus in the tenth and twelfth editions of his 'Systema Naturae,' A.D. 1758
and 1767. Trembley,* again, accepting this type as akin to the fresh-water polype,
with which his name is so eminently familiar, bestowed upon it the suggestive title
of " Polypes a bouquet." Both Ehrenberg and O. F. Muller report of this species
that it is an inhabitant of both salt and fresh water, but the present author is in-
duced to think that under the former conditions it has been confounded with the
somewhat similar, and more essentially marine type Zoothamnium arbuscula. De
Fromentel t represents the internal muscular fibrilla of the branching pedicle in this
species as transversely striate and capable of contracting spirally within its outer
sheath ; this outer sheath is also delineated by him as exhibiting closely approximated
transverse annulations. The somewhat similar interpretation of this structural
element submitted by Mr. H. E. Forrest in the ' Midland Naturalist' for April 1879,
is reproduced at PL XXXVI. Fig. 6. The author has on numerous occasions sought
to corroborate this accredited striated aspect of the central contractile fibrilla as
given by various writers in connection with Carchesium and other members of the
Vorticellidan family, but in no instance with success. In place of this, as recorded
in the preceding description of Vorticdla nebulifera, see p. 674, the central muscular
cord was found to be of apparent homogeneous consistence, but enclosed within
a separable delicate hyaline membrane, a representation of such structural differen-
tiation as observed in Carchesium polypinum being given at Fig. 3 of the accompany-
ing woodcut. According to the most recent investigations of T. W. Engelmann,J
the posterior or aboral circlet of cilia developed by the migrant zooids of this and
other Vorticellidae originates, as shown at PL XXXV. Figs. 30 and 31, from a
distinct annular ectoplasmic band, having the appearance, under moderate magnifi-
cation, of being simply obliquely striate, but which under more minute analysis is
resolved into closely approximated rows of granules upon which the cilia are
elevated. A diagrammatic outline of the oral and peristomal elements of the present
species, typifying likewise the same structures as common to all representatives of
the Vorticellidae, as given by Green*", is reproduced at PL XXXV. Fig. 51.

Carchesium spectabile, Ehr. PL. XXXVI. FIG. 26.

Bodies broadly and evenly campanulate, dilated anteriorly, subspheroidal
when contracted ; zoodendrium two lines in height, forming an obliquely
conical, or irregularly branching bush. HAB. — Fresh water.

The original illustration of this species, as given by R6sel,§ is herewith repro-
duced. The form next described, referred with doubt to this type by Claparede
and Lachmann, is regarded by the author as possessing sound claims for separate
specific recognition.

Carchesium Lachmanni, S. K. PL. XXXVI. FIG. 21.

Bodies elongate-conical or thimble-shaped, truncate and not dilated
anteriorly, pyriform and plicate 'anteriorly when contracted ;/ cuticular sur-
face finely striate transversely ; endoplast curved, longitudinally disposed,

* 'Phil. Trans.,' 1744. t ' Microzoaires,' 1876.

\ Pfliiger's ' Archiv Physiol.,' Bd. xxiii., 1880. § ' Insectenbelustigungen,' 1755.

Q 2

692 ORDER PERITRICHA.

presenting numerous sinuosities ; compound pedicle or zoodendrium not
articulate, branching in a subumbellate manner. Length of zooids 1-250".
HAB. — Fresh or almost stagnant water.

The figure and diagnosis of this species, as given by Messrs. Claparede and
Lachmann,* suffice to prove its distinctness from Carchesium spectabile, with which
they originally proposed to identify it. The authors quoted met with it in abundance
on the edges of the canal near the Place de I'OpeVa, Berlin, the water of which is
usually in a more or less fetid state. The individual animalcules, they report, are
nearly twice the size of those of C. polypinum.

Carchesium epistylidis, C. & L. PL. XXXVI. FIGS. 12-14.

Bodies elongate-conical, abruptly narrowed near their point of juncture
with the pedicle ; the peristome-border slightly dilated, pyriform but not
plicate when contracted ; the cuticular surface smooth ; zoodendrium
branching subdichotomously, more or less distinctly articulate, such articu-
lations usually occurring immediately beneath each bifurcation ; endoplast
band-like, curved, transversely disposed. Length of bodies 1-500".

HAB. — Pond and river water.

This species is described by Claparede and Lachmann as manifesting in its general
bearing the more rigid aspect of an Epistylis rather than that of a Carchesium, the
independently contractile properties of the separate pedicles determining, however,
its true position. The examples furnishing the original description of this type were
found attached in small colonies of five or six animalcules only to the bodies and
protective cases of the larvae of Phryganidae and other water insects. In the figure and
description given by the authors quoted, the former being reproduced at PI. XXXV.
Fig. 12, some four or five zooids only are reported as being included in a single
colony-stock. During the spring of the year 1879, the author, however, received
from Mr. H. E. Forrest, of Birmingham, drawings and specimens of a species
agreeing in all essential particulars with the present type, excepting that the colony-
stocks usually supported a considerably larger quantity of animalcules — varying in
number from eight or ten to as many as twenty or thirty — while the reported
habitat differed to the extent that they were found attached to willow-roots, the
polyzoaria of Plumatella repens, and other stationary objects. It was further observed
that the surface of the branching pedicle or zoodendrium was usually more or less
encrusted with a granular or flocculent deposit. In the original communication
received respecting this form, Mr. Forrest indicated its distinctness from Carchesium
polypinum in the following points : — " (i) In being more sluggish in its movements;
(2) in the contours of the animalcules, which are comparatively narrower ; (3) in the
presence of brown flocculent matter covering the surface of the pedicle (this possibly
accidental) ; (4) in the distinct division of the pedicle at intervals by transverse
septa, which usually occurs just below the point of dichotomy." It was at first
anticipated by the author that this very distinct form was probably identical with the
little known Carchesium spectabile previously described, but a subsequent reference
to the original delineation of that type, as given by Rosel, here reproduced, has not
supported such identification. A more careful analysis of its leading characteristics
has since elicited its entire correspondence, excepting for its more luxuriant form of
growth and non-parasitic habitat, with the C. epistylidis of Claparede and Lachmann,
and it is therefore here accepted as a local and prolific variety only of that form. As
all ecto- and endo-parasitic and commensal species may be held to have originally led
an independent existence, it might be reasonably predicated that the present luxuriant
and independent growth-form represents the more normal and primitive expression of

* ' Etudes sur les Infusoires,' 1868.

GENUS ZOOTHAMNIUM. 693

the type now under consideration. The illustrations given at Figs. 13 and 14 of the
accompanying plate, are reproduced from drawings of the species remitted by
Mr. Forrest, who obtained it in some abundance both in the river Avon, near
Evesham, and from the neighbourhood of Birmingham. Anticipating that the form
might be new to science, Mr. Forrest originally proposed to confer upon it the
distinctive title of Carchesium septatum.

Carchesium aselli, Engelmann. PL. XXXVI. FIG. 10.

Bodies elongate, subcylindrical, slightly constricted beneath the peri-
stome, about twice as long as broad ; peristome-border turgid, not dilated ;
ciliary disc raised but slightly above its margin ; vestibular cleft continued
but a short way backwards ; cuticular surface smooth ; contractile vesicle
close to the peristome-border ; endoplast band-like, curved ; zoodendrium
stout, branching at short intervals, not annulate or striate, largest colonies
including about twelve animalcules, usually two or four only. Length of
bodies 1-250". HAB. — Fresh water, on Asellus aquaticus.

Supplementary Species.

The minute Carchesium pygmaum of Ehrenberg, with animalcules that do not
exceed the 1-2400" in their greatest length, is evidently a Flagellate form, whose
exact identity cannot be predicated, but is apparently referable to one of the two
genera Anthophysa or Codosiga.

GENUS IX. ZOOTHAMNIUM, Ehrenberg.

Animalcules structurally identical with those of Vorticella, ovate,
pyriform or globular, often dissimilar in shape and of two sizes, stationed
at the extremities of a branching, highly contractile pedicle or zooden-
drium ; internal muscle of pedicle continuous throughout, not disconnected
as in Carchesium. Inhabiting both salt and fresh water.

As originally instituted by Ehrenberg, this genus was distinguished from
Carchesium merely on account of its bearing zooids of two forms and sizes on the
same tree-like colony. This character has, however, been found too uncertain for
retention, and has given way to the more substantial one, first pointed out by Stein,
having reference to the continuity throughout the branching pedicle of the contained
contractile muscular fibre. This last-named structural feature confers upon the
aggregated communities of this genus, as observed in the living state, a modification
of comportment that readily distinguishes them from those of Carchesium ; for
while in that genus each animalcule, having a separate contractile pedicle, is able
to extend itself and contract independently, the movements of the whole com-
munity in the case of Zoothamnirim are affected by that of a single unit, and one
contracting all the others follow suit. An additional feature distinctive of the genus
Zoothamnium is afforded by the position occupied by the contractile fibre with
relation to its hyaline investing sheath. In both Vorticella and Carchesium this con-
tractile cord exhibits a spiral, or optically a zigzag, disposition within its sheath,
such circumstance accounting for the elegant spiral form assumed by the structure
as a whole when contracted. In Zoothamnium, on the other hand, there is no
such spiral disposition, the contractile cord being axial and straight throughout : the
pedicle in its contracted state, as a necessary sequence, may present a plicate but
never a symmetrical spiral flexure. Examined with a high magnifying power, the
central cord in this genus, as first observed by Ehrenberg, displays a faintly longi-
tudinal striate aspect, and is pronounced by Claparede and Lachmann, and more

694 ORDER PERITRICHA.

recently by Greeff, to be composed of distinct but closely approximated muscular
fibrillae. .

The numerous species of the genus Zoothamnium may, for the purposes of
diagnosis, be conveniently separated into two groups, a and b, that shall include
respectively those in which the zooids of the same colony-stock resemble or differ
from each other in shape or size. In the polymorphic series the usually fewer and
larger zooids developed become separated from their pedicles, and after a short
migratory existence reattach themselves and lay the foundation of new colonies.

A.— ZOOIDS POLYMORPHIC.

Zoothamnium arbuscula, Ehr. PL. XXXVII. FIGS. 1-8 AND 25.

Bodies of two shapes and sizes, mostly conical-campanulate, others
spherical, grouped on a compound pedicle or zoodendrium which consists of
an upright main rachis, from the summit of which divaricate horizontally or
obliquely a greater or less number of attenuate, more or less dividing
secondary branches ; the more abundant and smaller campanulate zooids
thickly distributed upon these secondary ramifications, interspersed here and
there, mostly at the axillae, with the larger, comparatively rare, spheroidal
animalcules ; main rachis very thick, highly elastic, contracting in a zigzag
form. Length of the ordinary zooids 1-430", height of the entire zooden-
drium 1-4". HAB. — Fresh and salt water.

The colonies of this species often occur in such abundance on the front glasses
of the tanks of marine aquaria as to obscure clear vision, constant and considerable
labour being necessitated in their removal. Examined separately, each colony-stock
ma.y be compared to a minute crystalline standard fruit-tree, of which the ordinary
campanulate zooids may be likened to the leaves and the spheroidal or reproductive
units to the fruit. Except for the presence of the larger reproductive zooids, these
tree-like zoodendria bear no inconsiderable resemblance to those of Carchesium foly-
pinum, such similarity probably giving rise to the circumstance of the last-named
species being accredited by some authorities with both a salt- and fresh-water habitat.
That Zoothamnium arbuscula flourishes indifferently in both these media is at the
same time a well-authenticated fact, both salt- and fresh-water examples having been
recently remitted to the author by Mr. Thomas Bolton. The representation of the
contractile pedicle, given at PI. XXXVII. Fig. 25, is derived from the delineations
of the species given by Mr. H. E. Forrest in the ' Midland Naturalist ' for May
1879. While succeeding in detecting an obscure longitudinal striation of the central
muscular fibre, the author has been unable to define the existence of transverse strise
as depicted in this figure, neither does such a differentiation of this element appear
to have been recognized by any other investigator. The developmental phenomena
of the larger spheroidal zooids, also reproduced from Mr. Forrest's drawings, in
Figs. 6 and 7 of the same plate, accord with those hereafter described of Zoothamnium
alternans.

Zoothamnium niveum, Ehr. PL. XXXVII. FIGS. 13 AND 14.

Bodies of two sizes, the majority elongate-campanulate ; main stem of
the pedicle prolonged, sinuous or spiral, giving off short alternate or almost
verticillate branches, the spherical zooids of large size, situated near the
bases of the primary branches. Length of the ordinary zooids 1-210".

HAB. — Salt water.

GENUS ZOOTHAMNIUM. 695

The Zoothamnium plumosum of Dr. Strethill Wright,* and also the Zoothamnium
spirale of Mr. P. H. Gosse t must be regarded as identical with this form. The
lower branches are frequently entirely bare, the animalcules apparently dying off as
the zoodendrium becomes distally extended, while the upper portion, bending
under the weight of the living zooids, assumes an ostrich-plume-like aspect.
The delineation of this species, given in the accompanying plate, is derived
from an example dredged — attached to a Sertularian zoophyte — from a depth of
fifty fathoms, off the coast of Falmouth in July 1879, representing one of the several
interesting infusorial types obtained by the author in connection with the summer
excursion of the Birmingham Natural History Society. As first figured and described
by the author in the ' Midland Naturalist' for March 1880, this form was included
as a variety only of Zoothamnium alternans. A further acquaintance with the more
important modifications of the last-named species has, however, determined the
recognition "of Z. niveum as a distinct type.

Zoothamnium alternans, C. & L.
PL. XXXVI. FIGS. 22 AND 23, AND PL. XXXVII. FIGS. 20-24.

Bodies of various sizes, mostly subpyriform or fig-shaped, a few of
the larger ones spheroidal ; peristome thick, widely everted, its front
border in contracted examples puckered or plicate; cuticular surface
finely striate transversely ; zoodendrium consisting of an erect and basally
very thick main rachis, from which are given off, at sometimes opposite
but mostly alternate intervals, a greater or less number of but rarely
subdivided primary branches, upon which are borne at evenly separated
intervals the smaller and larger pyriform zooids, the still larger sized
spheroidal zooids situated usually at the axes or junctures of the branches
with the main stem ; the external surface of the compound pedicle finely
striate or annulate throughout. Length of smallest pyriform zooids 1-555"
to 1-425", of the largest pyriform and subspheroidal zooids 1-200".

HAS.— Salt water.

This species, while first discovered by Messrs. Claparede and Lachmann on the
Norwegian coast, was also met with by Greeff at Ostend, and has been frequently
obtained by the author, both in the Channel Islands and on the Devonshire coast,
attached to sea-weeds and to the polyparies of Sertularia and other littoral Hydrozoa.
It has been previously mentioned that the dendritic colonies of Zoothamnium arbuscula
present in their general mode of growth a fanciful resemblance to a symmetrically
grown standard fruit-tree ; adopting a like simile in the present instance, Z. alternans^
in its most luxuriantly developed state, may be compared to a carefully trained
espalier. Examples taken from widely separated or even contiguous localities
exhibit nevertheless a considerable latitude of variation, in some the side branches
being much longer than in others, while the zooids attached to these branches are
as often oppositely as alternately disposed. The chief illustration given of this
species, PI. XXXVII. Fig. 20, reproduced from Greeff, J represents an example in
which the branches are very long, and the former formula of arrangement pre-
dominates, while at Fig. 2 1 is a colony, from the author's sketch-book, in which the
branches themselves are reduced to their minimum, and represented by one or at
the most only two zooids ; between these two extremes every gradation of develop-
ment may be found. The striation of the cuticular surface of the zooids, as also the
annulation of the branching pedicle, is likewise subject to individual variation, being

* Pritchard's 'Infusoria,' p. 595, 1860. t 'Tenby,' pi. iv. fig. b, 1856.

t " Untersuchungen iiber die Naturgeschichte der Vorticellen," ' Wiegmann's Archiv,' xxxvii
1871.

696 ORDER PERITRICHA.

strongly marked in some instances and scarcely visible in others. In the two
colonies only of this species examined by Claparede and Lachmann, and in most of
those observed by the author, these striee and annulations were very conspicuous ;
while in those figured by Greeff the zooids are represented as perfectly smooth,
while the annulations of the branching pedicle are very few and far between. As
explained by its original discoverers, the somewhat abnormal alternate divarication
of the lateral branches, and more usually similar disposition of the zooids upon these
branches, are produced by the unequal growth of the two animalcules which result
from the primary process of longitudinal fission ; while one of these remains
stationary or produces but a short pedicle, the other passes on and after a short
interval repeats the process of subdivision.

It is upon the larger spheroidal zooids, as first intimated by Ehrenberg with regard
to the similar individuals in Z. arbuscula, that devolves the mission of becoming
detached and laying the foundation of future colonies. These larger animalcules are
at first similar in shape and size to the smaller pyriform units, but taking no share in
the further extension of the branching pedicle, increase greatly in size, retaining for
a time their pyriform outline, and ultimately assuming their characteristic spheroidal
contour. This last-named stage arrived at, a circlet of cilia is developed posteriorly,
as in the migrant zooids of Vorticella, and the animalcule shortly becomes detached
from the parent stalk and wanders away in search of a suitable site for reattachment.
The abnormal thickness of the basal portion of the branching pedicle in both Zootham-
nium arbuscula and the present species is explained by the light of these develop-
mental phenomena, its greater calibre being the natural product of a zooid of so
much greater a relative size than those which contribute to its further prolonga-
tion. The development by these spheroidal animalcules of the posterior ciliary
circlet, or their detachment from the parent stock, as observed by the author, and in
part by Claparede and Lachmann, does not appear to have been seen by Greeff.

Very recently, September 1880, the author has received through Mr. Thomas
Bolton, from the Aston Aquarium, examples of this species among which were
scattered one or two colony-stocks that bore supplementary zooids of an altogether
abnormal size and contour; these, as shown at PI. XXXVI. Figs. 22 a a and 23,
equalled in length the ordinary pyriform zooids, but were very slender — five or six
times as long as broad — while their cuticular surface was relatively coarsely annulate.
It is anticipated by the author that these attenuated zooids represent male units
destined to compass genetic union with the large subspheroidal and subsequently
detached animalcule of the normal colony-stocks. Phenomena substantiating this
anticipation have yet to be recorded ; even should this not be forthcoming, Zootham-
nium alternans will afford one of the most remarkable known instances of poly-
morphism among the Infusoria, in no other type being there three distinctly
differentiated zooidal forms.

Zoothamnium Cienkowskii, Wrz. PL. XXXVII. FIG. 15.

Animalcules of two sizes, but similar in shape, campanulate, attenuate
posteriorly ; cuticular surface smooth ; peristome-border thick, widely
dilated ; ciliary disc slightly elevated, the cilia surrounding it very
long and fine ; pedicle massive, dichotomously branched, supporting but
few zooids, at most seven or eight, but more usually only two or four, the
basal portion of the pedicle thickest, smooth, or finely striate longitudi-
nally, the remaining portion from the commencement of the branches trans-
versely wrinkled ; the main rachis slightly exceeding in height the length
of the larger zooids, the primary branches shorter than the secondary ones ;
contractile vesicle of extraordinary size ; endoplast band-like, curved,
transversely placed. Length of smaller zooids 1-665", °f larger ones
1-500". HAB. — Salt water.

GENUS ZOOTHAMNIUM. 697

This species as described by Wrzesniowski * is distinguished by the varied
character of the pedicle in its basal and distal regions, and by the abnormal size of
the contractile vesicle. This latter structure attains its fullest development in the
more abundant smaller zooids, and in which at full diastole it is of such large propor-
tions as to fill not only the ciliary disc, but to invade a large area of the parenchyma
beneath the peristome-border and in the neighbourhood of the pharynx. The con-
tractile fibrilla in this species commences a little beneath the junction of the smooth
basal with the wrinkled branching region of the pedicle, the entire colony-stock in
its state of contraction bending down obliquely from this point. The examples
supplying the type of this species were discovered by Wrzesniowski attached to
drifted seaweeds (Floridece) at Rugen in the Baltic.

Zoothamnium dichotomum, Wright. PL. XXXVII. FIGS. 9-12.

"Stem very regularly dichotomous ; pedicles long; zooids cylindrical,
resembling the fruit of the Rosa canina"

The above brief diagnosis is simply reproduced as it appears in Pritchard's
' Infusoria,' no dimensions or habitat that might assist towards the establishment of
its identity being furnished. The examples figured at PI. XXXVII. Figs. 9-12, as
presumably identical with the above-named species originally discovered by
Dr. Strethill Wright, were collected by the author in July 1879, °ff the coast of
Falmouth, being dredged in company with Zoothamnium spirale from a depth of
about fifty fathoms. The colony-stocks thus obtained differed, however, from those
examined by Dr. Wright in the circumstance that zooids of two shapes and sizes
were developed on the dichotomously branching zoodendria. The majority and
smaller of these were simply campanulate, while it was only the few larger repro-
ductive units, produced mostly toward the bases of the branches, either singly or in
clusters of two or three, that coincided by reason of their ovate shape with the
foregoing diagnosis. As some few examples were met with in which while all the
ordinary campanulate animalcules had become detached, the larger ovate zooids
remained in situ, it would seem highly probable that the specimens upon which
Dr. Wright framed his brief description were similarly imperfect. It was observed
of the Falmouth specimens that while the normal campanulate zooids were, under
a magnification of two hundred diameters, perfectly smooth, the cuticular surface of
the larger ovate ones was very distinctly striate in a transverse direction.

B.— Zooms SIMILAR IN SHAPE AND SIZE — HOMOMORPHIC.

Zoothamnium gleniscum, C. & L. PL. XXXVI. FIGS. 24 AND 25.

Animalcules pyriform, similar in shape and size, disposed alternately on
the parent branch ; their cuticular surface smooth ; pedicle finely striate
transversely, usually articulate at intervals about midway between each
subdivision. Dimensions unrecorded.

HAB.— Salt water, North Sea (C. & L.).

This species is described by Claparede and Lachmann as closely resembling
Zoothamnium alternans, from which, however, it is to be distinguished by the more
slender articulate pedicle. The zooids are, moreover, estimated to be twice as large
as those of the last-mentioned variety, although their exact dimensions were not re-
corded. The articulations of the pedicle do not correspond with each bifurcation of
the stem as in the Carchesium epistylidis of the same authors, which it also closely
resembles, but one or more joints intervene between each such subdivision.

'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxix.. 1877.

698 ORDER PERITRICHA.

Zoothamnium afflne, Stein. PL. XXXVI. FIG. 16.

Bodies of animalcules ovate, twice as long as broad, somewhat con-
tracted posteriorly, truncate in front, and surmounted by a thick tumid
peristome of rather less diameter than that of the centre of the body ;
cuticular surface smooth ; pedicle very thick, dividing dichotomously, the
branches often attaining a nearly equal degree of elevation, but the general
contour varying considerably in different colonies ; surface of the pedicle
smooth during extension, but transversely plicate in the contracted state ;
endoplast semicircular, band-like, lying transversely with the axis of the
body ; no secondary spherical zooids. Length of individual 1-380" to
1-270". HAB. — Fresh water, on aquatic insects and Entomostraca.

The relatively abnormal thickness of the pedicle of this species serves to dis-
tinguish it readily from most other known forms ; while this structure is described
in its diagnosis as being perfectly smooth except in its contracted conditions, the
figures given by Stein, here reproduced, represent it with equally conspicuous
transverse plicae in both its extended and contracted states. The author has
recently, February 1879, met with small colonies of this animalcule attached to
the Amphipod Gammarus pulex taken from a running stream among Callitricha,
in the neighbourhood of St. Heliers, Jersey. In no instance were more than four
zooids attached to a single zoodendrium, while the greatest height of the latter
structure was less than that of the extended bodies.

Zoothamnium parasita, Stein. PL. XXXVII. FIG. 16.

Animalcules minute, ovato-fusiform, tapering posteriorly, scarcely one
and a half times as long as broad ; peristome-border thick, narrower than
the centre of the body ; ciliary disk slightly elevated ; cuticular surface
smooth ; a few, usually two, zooids only supported upon a short, smooth,
and comparatively slender, dichotomously dividing pedicle, whose entire
height does not equal that of a single zooid. Length of bodies 1-350".

HAB. — Fresh water, on Cyclops quadricornis and other Entomostraca.

The form referred to this species by D'Udekem * and found on Asellus aquaticus,
would seem to be more correctly referable to the species last described. The bodies
of the zooids are comparatively larger and the pedicle thicker and more corrugate
than is reported by Stein of the present type.

Zoothamnium nutans, C. & L. PL. XXXVI. FIGS. 9 AND 15.

Animalcules few in number, one or two zooids only associated in a
single colony-stock, campanulate, slightly gibbous, attached obliquely to
a long, smooth, slender and articulate pedicle ; peristome-border widely
dilated ; surface of the cuticle finely and obliquely striate ; pedicle con-
tracting in a zigzag and not a spiral manner. Length of zooids 1-350".

HAB.— Salt water : Bergen (C. & L.). ;

Zoothamnium aselli, C. & L.

Animalcules elongate, subcylindrical, three times as long as broad,
attenuate posteriorly, attached in numbers to a very thick, smooth, inarticu-

* 'Infusoires de la Belgique,' 1864.

GENUS ZOOTHAMNIUM. 699

late, dichotomously branching pedicle ; endoplast small, oval. Dimensions
of individual zooids unrecorded. Height of entire colony-stock 2 lines Fr.

HAB. — Fresh water : on Asellus aquaticus and various aquatic insects
and Crustacea.

M. Claparede, in describing this species from the drawings only of M. Lach-
mann, remarks upon the very robust aspect of the animalcules, the outer cuticle
being more indurated than in any other known representative of the genus. In
this last respect, and also in the shape of the zooids, it is recognized by him as pre-
senting some resemblance to Epistylis plicatilis. It would seem to be by no means
improbable that the Carchesium asdli, subsequently described by T. W. Engelmann, is
identical with this form.

Zoothamniuxn elegans, D'Udk.

Bodies subpyriform, slightly gibbous ; the peristomal border widely
dilated, tapering and attenuate posteriorly ; pedicle slender, smooth, and
transparent, neither striate nor articulate, sparsely branching at its distal
extremity, supporting but a small number of zooids, which occupy a
closely approximate altitude ; ciliary disc projecting conspicuously beyond
the peristome-border ; pharyngeal cleft distinct, extending backwards
beyond the centre of the body ; endoplast ribbon-shaped, curved ; con-
tractile vesicle situated close to the entrance of the vestibulum. Length of
bodies 1-300". HAB. — Salt and fresh water : Ostend (D'Udk).

The occurrence of Amphileptus meleagris as a devouring parasite of the colonies
of this species, as first observed by Claparede and Lachmann, in association with
Epistylis plicatilis and Carchesium polypinum, was frequently observed byD'Udekem,
and receives attention in the description given of the above-named Holotrichous
animalcule.

Zoothamnium macrostylum, D'Udk. PL. XXXIX. FIG. 30.

Bodies elliptical or subcylindrical, about twice as long as broad, equally
rounded at the two extremities ; cuticular surface smooth, colony usually
consisting of two animalcules only, seated on a short, very massive, slightly
contractile, and longitudinally striate pedicle, whose height does not equal
that of the bodies of the zooids ; vibratile disc projecting but little beyond
the front border of the peristome ; endoplast rounded. Dimensions unre-
corded. HAB. — Fresh water, on Asellus fluviatilis.

This species would appear to closely resemble the Opercularia Lichtensteinii of
Stein.

Zoothamnium pictum, From.

Animalcules few in number, subspherical, smooth, hyaline, attached by
long pedicles to the slender main rachis, each zooid enclosing posteriorly
two green corpuscles. Length of bodies 1-1600". HAB. — Fresh water.

This form is so insufficiently described and figured by De Fromentel as to be
difficult to identify as a genuine Zoothamnium. While referring it to this genus its
describer hazards a doubt whether or not it is referable to the Vorticdla picta of
Ehrenberg, he having likewise a short while previously expressed uncertainty
concerning the identity of his newly introduced Vorticdla microscopica with the

700 ORDER PERITRICHA.

same Ehrenbergian species, both of which possess a broadly campanulated contour
altogether distinct from the present type. Only two animalcules constitute the
colony-stock of this species as figured by De Fromentel, their aspect correspond-
ing most nearly with that of two abnormally united Vorticellce.

Zoothamnium marinum, Mereschk. PL. XXXVI. FIG. n.

Bodies conical, campanulate, somewhat gibbous, pyriform and evenly
puckered anteriorly when contracted ; the peristome-border dilated and
obliquely truncate ; the ciliary disc moderately elevated ; pharyngeal cleft
conspicuously developed ; cuticular surface entirely smooth ; parenchyma
finely granulate ; endoplast ovate, minute ; pedicle neither striate nor
articulate, branching in a perfectly even dichotomous manner, supporting
from four to eight or twelve animalcules only. Length of bodies (in spirit)
1-240".

HAB. — Salt water : White Sea (Mereschkowsky), attached to seaweeds
and zoophytes at depths of from 5 to 1 2 fathoms.

A species apparently allied to, if not identical with, this type has been obtained
by the author at St. Heliers, Jersey, attached to the carapace and setose appendages
of the common shore-crab Cartinus m<znas, and will be found figured at PI.
XXXVII. Figs. 17-20, in connection with the provisional title of Zoothamnium
carcini.

Zoothamnium simplex, S. K. PL. XXXVI. FIGS. 17-20.

Bodies when extended elongate-conical, the anterior border widest,
tapering gradually thence to the attenuate posterior extremity, from three
to four times as long as broad ; pyriform when contracted ; stationed in a
single cluster of seldom more than half a dozen zooids at the extremity of
a simple, unbranched, rarely and slowly contracting pedicle, whose altitude
equals about twice the length of an extended zooid ; ciliary disc moderately
elevated above the peristome-border ; cuticular surface smooth, finely
granular ; endoplast elongate, attenuate, longitudinally placed. Length of
extended bodies 1-300". HAB. — Pond water.

This species was obtained by the author in November 1880, attached in some
abundance to the leaves of Myriophyllum and other aquatic plants growing in a fresh-
water aquarium, its original derivation being uncertain. The disposition of the animal-
cules in a single group at the extremity of a simple pedicle distinguishes it con-
spicuously from all known representatives of the genus, the elongate contour of the
bodies, at the same time, while differing from all members of the allied genera
Zoothamnium and Carchesium, closely resemble those of Epistylis plicatilis. The
pedicle, as in Carchesium epistylidis, is remarkable for its rare and sluggish contrac-
tion. In one instance, as represented at PI. XXXVI. Fig. 20, the conjugation of a
minute migrant and normal sized sedendary zooid was observed.

GENUS X. EPISTYLIS, Ehrenberg.

Animalcules campanulate, ovate or pyriform, corresponding structurally
with those of Vorticella, attached in numbers to a rigid, uncontractile, more
or less branching, tree-like pedicle or zoodendrium ; the zooids usually of
similar size and shape. Inhabiting salt and fresh water.

GENUS EPISTYLIS. 701

Epistylis galea, Ehr. PL. XXXIX. FIG. 6.

Bodies elongate-conical, about three times as long as broad, attenuate
posteriorly, the frontal margin dilated ; cuticular surface smooth and plastic,
exhibiting transverse folds posteriorly when contracted ; vestibular entrance
prominent, projecting laterally in a spout-like manner ; zoodendrium rela-
tively short, thick, profusely and dichotomously branched ; secondary
branches not exceeding the zooids in length, articulate at each bifurcation.
Length of bodies 1-120"; height of entire colony 1-24".

HAB. — Fresh water, on Ceratophyllum and other water-plants.

In its general mode of growth the branching pedicle of this species accords most
nearly with that of Epistylis digitalis, but is readily distinguished from that type by
its simply articulate ornamentation ; the contour of the supported zooids at the same
time somewhat resembles that of Epistylis plicatih 's, a similar transverse plication of
the posterior region of the body being furthermore exhibited during contraction.

Epistylis anastatica, Linn. sp. PL. XXXVIII. FIGS. 19-22.

Bodies in extension conical-campanulate, nearly three times as long
as broad, attenuate posteriorly, the frontal margin dilated, spheroidal or
ovate, with a snout-like projection when contracted; cuticular surface
smooth, or finely striate transversely ; the ciliary disc raised above the
border of the peristome in a tongue-like form ; pedicle moderately thick,
entirely smooth, neither striate nor articulate, often squamose through
the adherence of other minute parasitic forms, branching profusely and
dichotomously, secondary branches attenuate, equal to or exceeding the
length of the zooids. Length of bodies 1-280" ; height of entire colony
1-15". HAB. — Fresh water, on Entomostraca and aquatic plants.

The entirely smooth pedicle and more attenuate character of the secondary
branches, as well as the considerably smaller size of the zooids, distinguishes this
species from the preceding ; this same character of the pedicle, added to the greater
dilation of the peristome-border, separates it also from E. digitalis, in whose com-
pany it not unfrequently occurs. In examples recently examined the author has
detected the presence of fine transverse striae upon the cuticular surface, though
these are not so conspicuous as to be generally observable. Ehrenberg remarks that
the branching pedicle of the colonies found growing on water-plants is usually more
attenuate than when attached to Cyclops quadricornis or other animal hosts. By
Linnaeus,* as also by O. F. Miiller, this species is described under the title of Vorti-
cella anastatica.

Epistylis plicatilis, Ehr.
PL. XXXVIII. FIGS. 6-8, AND PL. XXXIX. FIGS. 12-15.

Bodies elongate-conical, attenuate posteriorly, three or four times as long
as broad ; cuticular surface soft and flexible, plicate, or exhibiting several
annular folds posteriorly when contracted ; the frontal margin dilated ; the
ciliary disc much elevated ; pedicle slender, finely striate longitudinally,
profusely and dichotomously branched, often corymbose, the secondary

* 'Systema Naturae," Ed. xii., 1767.

702 ORDER PERITRICHA.

branches attenuate, three or four times longer than the extended bodies,
the thicker and undivided basal portion comparatively short. Length of
zooids 1-280" to 1-145" 5 height of entire colony 1-9".

HAB. — Fresh water, attached to the shells of Mollusca, Limnceus
stagnalis, and various water-plants.

This species may be easily recognized by the characteristic plicate or folded
contour of the posterior extremity of the zooids at the time of contraction, and by the
great relative length of the secondary divisions of the pedicle. The conjugation of
neighbouring animalcules of this species and the development from the endoplast of
ciliate embryos has been observed by Claparede and Lachmann ; illustrations of the
last-named phenomenon, reproduced from their drawings, are given at PL XXXIX.
Figs. 12-15. The branching pedicle or zoodendrium of Epistylis plicatilis frequently
gives support to colonies of a minute collared flagellate type apparently identical
with Monosiga Steinii. These may either completely encrust it with their aggre-
gated numbers or be distributed in isolated or scattered groups, as shown at a a in
PL XXXVIII. Fig. 6.

Epistylis flavicans, Ehr.
PL. XXXV. FIGS. 48-50, AND PL. XXXVIII. FIGS. 1-5.

Bodies in extension broadly campanulate, soft and flexible, widely
dilated anteriorly, subspherical when concentrated ; parenchyma usually of
a yellowish hue ; cuticular surface very finely striate transversely ; peri-
stome-border not thickened, much revolute, the ciliary wreath bearing five
or six convolutions of long, powerful cilia ; pedicle exhibiting two leading
modifications: in its younger and more robust phase dendriform, slender,
erect, profusely and dichotomously branching, the ultimate ramifications
short, not half the length of the zooids, widely divergent ; the older colonies
decumbent, the pedicle weak and straggling, rarely branching. Length of
zooids 1-192" to 1-70". HAB. — Fresh water, on aquatic plants.

Under the title of Epistylis flavicans is here included the E. flavicans and
E. grandis of C. G. Ehrenberg. Both Stein and Claparede and Lachmann ex-
pressed doubts concerning the specific independence of these types, and Professor
Wrzesniowski, with whom the author's investigations in this same direction accord,
has recently * brought forward conclusive evidence in demonstration of their identity.
As shown by this last-named authority, the type described by Ehrenberg under the
title of E, flavicans represents the earlier, erect, and more robust growth of the
• animalcules, which in later generations lose their power of secreting a rigid stalk,
become larger and more turgid, and falling down develop a more or less matted,
horizontal layer of lax, thread-like, rarely dividing filaments, presenting under such
conditions all the characteristics of Ehrenberg's Epistylis grandis. Data of the
highest interest have been recorded by Greefff respecting the reproductive pheno-
mena of this species. By him, certain members of the erect colonies were observed
to become divided by fission into two, four, and ultimately into rosette-like groups of
eight minute, pyriform zooids, which developing respectively a posterior circlet
of cilia, were liberated into the surrounding water. These minute liberated zooids
were further observed to effect a junction, or to coalesce, with the ordinary attached
animalcules, fixing themselves to their sides, and penetrating into the substance of

* ' Zeitschrift fur "Wissenschaftliche Zoologie,' Bd. xxix., 1877.
t ' Archiv fur Naturgeschichte,' 1870.

GENUS EPISTYLIS. 703

their parenchyma after the manner of conjugating Vorticella. At PI. XXXVIII.
Fig. i, Greeff's admirable illustration of a colony of this species is reproduced,
showing the various stages of development of the rosette-shaped clusters, and the
conjugation of the detached units with the normal zooids. This same authority
reports having observed, scattered beneath the cuticular layer of E. flavicans, minute
ovate capsular bodies (PI. XXXVIII. Figs. 4 and 5) that contain an extensile filament,
and closely corresponding in structure with the thread-cells, or nematocysts, of the
Ccelenterata. Such structures have not been detected in connection with this species
by any other observer, and the irregularity of their distribution as figured by Greeff
inclines the author to regard them, as in the case of Polykrikos, as of adventitious
origin. Two peculiarities pertain to the pedicle of the normal or erect type of this
species that serve to distinguish it from any other known representative of the
genus. In the first place, between the joints, which are solid, the structure is hollow
throughout, like the culm of a grass ; while secondly, these joints are tumid, and each
limb of the accompanying bifurcation exhibits towards its base a more or less
conspicuous lyrate or coarctate curvature. As with various other species of
Epistylis, this branching pedicle is frequently found incrusted with minute Flagellate
and other infusorial types. Greeff figures as growing upon examples examined by
him, a species evidently identical with Stein's Salpingceca convaljaria, while upon
the same host the author has frequently observed a species QiMonosiga and extensive
colonies of the minute Acinete form Podophrya carchesii.

The soft-stemmed recumbent variety of this species, synonymous with the
Epistylis grandis of Ehrenberg, and which may be appropriately distinguished by the
title of E. flavicans var. decumbens, is perhaps better known and apparently more
plentifully distributed than the upright form, in consequence of the great extent of the
colony-masses it produces. These often constitute prominent objects to the unassisted
vision, taking the form of a white, granular slime, which may completely cover the roots
and leaves of water-plants, or spread like a grey felty mass over the side walls of the
tanks of an aquarium. The bodies of this recumbent variety attain a considerably larger
size than those found in the stiff-stemmed examples, and are usually of a brownish hue,
and exceedingly granular and opaque ; their substance is also more soft and plastic,
permitting the animalcules to assume a great variety of plicate and variously distorted
contours. No member of the family of the Vorticellidae probably possesses so
powerful and voluminous an adoral fringe of cilia as appertains to the present
species. It is represented by Wrzesniowski as forming four and a half convolutions
only ; the author, has, however, ascertained that there are no less than five and a
half or six turns to the spire. This was clearly demonstrated in examples isolated
for some time in a damp chamber ; the zooids at the end of two days became de-
tached from their supporting pedicles, assumed a subglobose form, and shed all
their cilia, presenting then the aspect shown at PI. XXXVIII. Fig. 3, in which
the convolution of this structure was most clearly exhibited. The detached cilia
remained scattered around them for a considerable interval, but ultimately disin-
tegrated. The under surface of dead leaves fallen into the water, as also the roots
and leaves of water-lilies, Nymphcea and Nuphar, are always a favourite haunt of
this attractive species. As evidence of its longevity it may be mentioned that
colony-stocks cultivated by the author in an aquarium have lasted for a period of no
less than six months, dating from November 1880 to June 1881, becoming metamor-
phosed within that period from erect tree-like colonies of two, four, or eight
animalcules only, to sessile masses equalling or exceeding the size of hazel-nuts. It
was further noted in connection with these colonies that examples isolated for
examination in a zoophyte-trough abandoned, within a few hours, their compact and
erect mode of growth for the lax and attenuate formula characteristic of the variety
decumbens. The brief absence of their customary food-supply was apparently quite
sufficient to bring about the recorded metamorphosis.

704 ORDER PERITRICHA.

Epistylis digitalis, Ehr. PL. XXXVIII. FIGS. 12-16.

Bodies in extension elongate, cylindrical-campanulate, somewhat gib-
bous, from two or three to nearly four times as long as broad ; elongate-
pyriform, with an anterior nipple-like projection, when contracted ; the
frontal margin but slightly dilated, obliquely truncate ; ciliary disc consider-
ably elevated ; cuticular surface conspicuously striate transversely ; pedicle
thick, profusely and dichotomously branched, coarsely and closely annulate,
secondary ramifications of the pedicle short, rarely equalling the length of
the extended zooids. Length of bodies 1-430" to 1-240" ; height of the
tree-like colony 1-16".

HAB. — Fresh water, on various species of Cyclops and other Ento-
mostraca.

This species is one of the most abundant representatives of the genus, being
rarely absent where Cyclops is plentiful, the limbs and carapace of this little Ento-
mostracon being often completely hidden beneath a perfect forest of its tree-like
colonies. Difficulty is sometimes experienced in separating this type from Epistylis
anastatica and E. galea previously described, but disappears on attention being
directed to the exceedingly distinct annulation of the entire pedicle and the elongate
and subcylindrical shape of the extended zooids. The more usually somewhat
gibbous, anteriorly oblique truncate contour of the animalcules, as seen in profile, so
nearly resembles that of the flower of the foxglove, Digitalis, as to have suggested
the title conferred upon it by Ehrenberg. When first taken from its native pond it
is remarkable, unless carefully handled, how soon the zooids of this species develop
a posterior circlet of cilia and become detached from the parent tree, nothing but
the bare twigs of this last-named structure being frequently left within a few hours
from the time of their collection. The detached animalcules will, however, on such
occasions be found abundantly distributed in the water, swimming rapidly about, and,
as observed by the author, with the posterior extremity directed in advance, or
creeping over the surface of submerged objects, with the aid of the closely applied
basal region and supplementary ciliary girdle, after the manner of a Trichodina or
migrant Vorticella. Left undisturbed, and with an abundant supply of water, for a
few days, many of these nomadic individuals find their way back to their previous
hosts, and commence severally the edification of a new family tree. At PI. XXXVIII.
Fig. 13 is given an illustration of an exceedingly attenuate variety of this species
observed on one occasion. In this instance the bodies of the extended zooids were
almost vermicular, their diameter in the centre scarcely exceeding twice that of the
supporting pedicle.

Epistylis leucoa, Ehr. PL. XXXIX. FIG. 4.

Bodies broadly campanulate, convex anteriorly, somewhat gibbous ;
peristome-border dilated ; ciliary disc projecting in a dome-like manner ;
parenchyma transparent, cuticular surface smooth ; pedicle erect, thick,
smooth, solid, and articulate at the joints ; its branches very short, capitate ;
endoplasts band-like or S-shaped. Length of bodies 1-120"; of the entire
zoodendrium 1-24". HAB. — Fresh water.

This species was obtained by Ehrenberg attached to the leaves of sedges in the
ponds of the Berlin Zoological Gardens, in January 1835, ice at the time covering the
surface of the water. In shape and size the zooids would appear to most closely re-
semble those of E. flavicans var. decumbens, but the ciliary disc is represented as much
more prominent ; the pedicle is also, in addition to being articulated, considerably

GENUS EPISTYLIS. 705

stouter, solid, and with very short secondary branches. According to Ehrenberg's
figures, this type appears to form but small colonies, six zooids only being included
in the one selected by him for illustration. No recent investigator would appear
so far to have made the acquaintanceship of this animalcule. The examples referred
to this type by Mr. H. E. Forrest in the 'Midland Naturalist' for April 1879,
undoubtedly represent the erect variety of Epistylis flavicans.

Epistylis branchiopyla, Perty. PL. XXXIX. FIGS, i AND 2.

Bodies shortly ovate or subspheroidal, nearly as broad as long, widest
centrally, tapering posteriorly, slightly constricted beneath the border
of the peristome ; ciliary disc slightly protrusible ; cuticular surface
smooth ; pedicle erect, slightly curved, finely striate longitudinally,
branching dichotomously but somewhat unevenly, one limb at each bifur-
cation, and continually on the same side, considerably exceeding the
opposite one in height ; endoplast band-like, transversely placed. Length
of bodies 1-360" to 1-280".

HAB. — Fresh water, on the larvae of Phryganida.

The species according with the above diagnosis and delineated in the accompany-
ing plate, is referred by Stein with some doubt to the E. branchiopyla of Perty, which
is but imperfectly described and illustrated. In accordance with Perty's original
figure, the pedicle consists of a thick erect main trunk, from which diverge laterally
and at close alternate intervals a few short slender stalks bearing the subspheroidal
zooids, a group of three or four similarly stalked zooids crowning the summit of this
trunk. Should this interpretation be correct, Perty's species, as recognized by Stein,
differs in the formation of its pedicle from all ordinary representatives of the genus
Epistylis, and more nearly approaches that of Zoothamnium alternans. It is at the
same time possible that this aberrant formula represents the impression conveyed
to Perty by the irregular branching of the pedicle characteristic of Stein's examples,
the size of the animalcules and the nature of the associated host being in both
instances identical. It may be mentioned that the zooids as figured and described
by Perty, while subspheroidal, exhibit a somewhat different outline from that given
by Stein, the posterior region being usually the broadest and somewhat flattened,
while the peristome- border is contracted, and represents the narrowest region of
the body.

Epistylis crassicollis, Stein. PL. XXXIX. FIG. 19.

Bodies ovate, or shortly fusiform, tapering posteriorly, as also in a
less degree anteriorly, about twice as long as broad ; peristome-border
greatly thickened, its diameter less than that of the centre of the body ;
ciliary disc scarcely exsert ; cuticular surface smooth ; pedicle branching
dichotomously, and at an acute angle, the individual zooids being usually
brought near together on the same level ; both main stem and branches
smooth, or faintly wrinkled transversely, the latter straight and of uniform
thickness, equalling in length the supported zooids, frequently with a
conspicuous raised annulus at the point of bifurcation; endoplast band-
like, horseshoe-shaped. Length of bodies 1-240".

HAB. — Fresh water, attached to the limbs of various Entomostraca.

The largest colonies of this species contain from twelve to twenty zooids, but
a less number is more abundant. In its general mode of growth it most closely
approaches Epistylis anastatica.

VOL. II. R

706 ORDER PERITRICHA.

Epistylis invaginata, C. & L. PL. XXXIX. FIG. 18.

Bodies of animalcules conical, thimble-shaped, one and a half times as
long as broad ; peristome-border widest, everted ; cuticular surface smooth ;
pedicle erect, unstriate ; secondary branches long and slender ; endoplast
ribbon-shaped, slightly curved, longitudinally disposed ; colonies comprising
but few zooids. Length of bodies 1-400".

HAB. — Fresh water, on aquatic insects.

Claparede and Lachmann remark that the species most nearly resembling this type
is the E. branchiopyla as described by Stein, but from which it may be distinguished
by the more elongate form of the body, the smooth surface and even development of
the pedicle, and the longitudinal instead of transverse position of the endoplast. The
specific name conferred upon this type bears reference to the contour assumed by
the animalcule in its migrant or free-swimming state, the posterior extremity being
at such times invaginated or thrust into the substance of the body, in a manner
closely identical with that observed by the author under similar conditions of Vorti-
cella striata. The examples of this species examined by its discoverers were found
attached to the abdominal segments of the larvse of a Hydrophihis.

Epistylis timbilicata, C. & L. PL. XXXVIII. FIG. 9.

Bodies ovoid, narrowest and slightly constricted anteriorly ; the peri-
stome-border not dilated ; ciliary disc produced centrally in the form of an
umbilicus; pedicle thick, short, smooth, and evenly branched, its total
height scarcely exceeding that of an expanded zooid. Length of extended
bodies 1-400."

HAB. — Fresh water, on the larvae of the common gnat, Culex pipiens,
forming colonies of but few zooids.

Although not mentioned by Claparede and Lachmann in their descriptive text,
their drawing given of the species represents the surface of the integument as finely
striate transversely. D'Udekem * has since obtained this variety from the neighbour-
hood of Brussels, his illustration of an adult colony-stock being here reproduced.
In their contracted state, according to this observer, the zooids become plicate
posteriorly, while the anterior region is produced in a snout-like manner.

Epistylis coarctata, C. & L. PL. XXXVIII. FIGS. 10 AND u.

Bodies ovato-fusiform, a little over twice as long as broad, inflated
centrally, tapering subequally towards both the anterior and the pos-
terior extremities ; cuticular surface smooth ; peristome-border very narrow
and contracted ; endoplast band-like, curved, transversely placed ; pedicle
sinuous, very slender, smooth, sparingly branched, secondary ramifications
supporting the zooids usually very short. Length of bodies 1-500".

HAB. — On Mollusca and vegetable debris from pond and sometimes
stagnant water, in the neighbourhood of Berlin (C. & L.). Colonies small,
consisting usually of but three or four animalcules.

This very graceful type is distinguished by its slender, fusiform contour, and
exceedingly narrow peristome, in both of which respects it would appear to
somewhat resemble the Opercularia stenostomata of Stein. From this last-named

* 'Infusoires de la Belgiqne," 1864.

GENUS EPISTYLIS. 707

species its describers report it as differing in its larger size, and in the more slender
and attenuate proportions of the secondary pedicles, which while short are never so
abridged as to impart to the bodies that sessile aspect which characterizes Stein's
species. The author refers without hesitation to Claparede and Lachmann's type
the unnamed Epistylis figured by Mr. H. J. Slack, in his ' Marvels of Pond-life,'
p. 95, 1861. The group there delineated, and reproduced at PI. XXXVIII. Fig. n,
would appear to be a remarkably luxuriant example, the branching pedicle support-
ing no less than seven zooids in place of the three, or four at most, only observed
by its original discoverers.

Epistylis tubificis, D'Udk. PL. XXXIX. FIGS. 7 AND 8.

Bodies subcylindrical, thimble-shaped, about twice as long as broad, the
frontal margin truncate, widest, moderately dilated, the posterior extremity
rounded and slightly tapering ; pendulous, and irregularly plicate trans-
versely when contracted ; pedicle short, slender, smooth, and transparent,
branching dichotomously ; basal stem scarcely equalling the length of an
extended zooid and each successive ramification decreasing in length ; entire
colony-stock comprising six or eight zooids only. Length of bodies 1-250".

HAB. — Fresh water, on Tubifex rivulorum.

Among the figures given of this species D'Udekem represents an animalcule
having the posterior portion of its body extended in an irregularly lobate manner
(see PI. XXXIX. Fig. 8), and which may perhaps be interpreted as a semi-
amoeboid phase, analogous to that prevalent among the Flagellata previous to
entering upon an encysted state. In their contracted condition the zooids assume
a reflected or pendulous posture closely resembling that of Opercularia nutans.

Epistylis pyriformis, D'Udk.

Bodies when extended, subfusiform, rather over twice as long as broad,
narrowest posteriorly, the cuticular surface smooth ; pyriform, with several
transverse posterior plications, when contracted ; peristomal border slightly
everted ; ciliary disc elevated but a small way above its margin ; pedicle
moderately stout, smooth and transparent, forming short, regular, widely
divergent dichotomous branchlets, neither these nor the main stem equalling
in length an extended animalcule. Colonies small, including five or six
zooids only. Length of body 1-250".

HAB. — Pond water, on the larvae of Tipula, mostly attached to the
posterior extremity.

Excepting for the more fusiform contour of the zooids, and the normal posture
maintained by them when contracted, this species may be readily confounded with
the one previously described.

Epistylis articulata, From. PL. XXXIX. FIG. 3.

Bodies elongate-conical, tapering posteriorly, somewhat gibbous, nearly
three times as long as broad ; cuticular surface smooth ; peristome-border
slightly dilated ; ciliary disc moderately elevated ; vestibular seta con-
spicuously developed; pedicle dichotomous, short, stout, and sparingly

R 2

708 ORDER PERITRICHA.

branched, striate longitudinally, articulate at one or two intervals between
each bifurcation. Length of bodies 1-325". HAB. — Freshwater.

In shape the animalcules of this species appear to closely resemble those of
Epistylis plicatilis, and it is a question whether the chief point of difference cited
by De Fromentel, that of the articulation at distant intervals of the pedicle, is
sufficient to distinguish them ; more especially as, in the last-named form, Stein has
remarked that old specimens are similarly jointed. No mention is made as to the
form assumed by the zooids when in the state of contraction, which would have
been useful in the settlement of this supposed identity, nor as to whether the species
forms large or small colonies. In the example figured, upon which the above
diagnosis is based, there are four ultimate branches to the pedicle, the lengths of the
main shaft and of the two primary ramifications in both cases scarcely exceeding
respectively those of the extended zooids.

Epistylis nympharum, Eng. PL. XXXVIII. FIG. 18.

Bodies elongate, subfusiform, about two and a half times as long as broad,
tapering chiefly posteriorly, and more slightly towards the anterior border ;
peristome somewhat oblique, its border turgid, not dilated ; ciliary disc
slightly elevated ; vestibular cleft developed backwards to or beyond the
centre of the body, exhibiting on the ventral side a knee-like flexure ;
cuticular surface smooth ; contractile vesicle located beneath the border of
the peristome ; endoplast elongate, band-like, longitudinally placed ; pedicle
short, smooth, or obscurely wrinkled, moderately thick, sparsely and dichoto-
mously branched. Length of bodies 1-166"'

HAB. — Fresh water, on aquatic larvae ; colonies including but a few
zooids.

The contour of the zooids in this species are recognized by Engelmann* as in
some respects resembling that of Epistylis digitalis, from which, however, it may be
readily distinguished by the smooth character of both the pedicle and cuticular
surface.

Epistylis Steinii, Wrz. PL. XXXVIII. FIG. 17.

Bodies conico-campanulate, tapering posteriorly, about twice as long
as broad ; peristome-border thick, moderately dilated ; ciliary disc dome-
shaped, scarcely exsert ; cuticular surface finely striate transversely ;
pharyngeal cleft prolonged beyond the centre of the body ; pedicle short,
exceedingly thick, sparingly divided, coarsely and irregularly wrinkled
transversely, its diameter increasing as it approaches its junction with the
animalcule's body, and whose width at this point it nearly equals, per-
forated by a conspicuous central canal ; endoplast band-like, transversely
placed ; contractile vesicle situated beneath the peristome-border, on the
right-hand side of the vestibulum. Length of bodies 1-640" ; altitude of
pedicle less than that of the extended zooids.

HAB. — Fresh water, on Gammarus pulex; colonies including but few
animalcules.

The short wrinkled character of the pedicle distinguishes this species from any
known representative of the genus; this structure, however, as remarked by

* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xi., 1862.

GENUS EPISTYLIS. 709

Wrzesniowski,* closely resembles that of Opercularia Licktensteinii, and it might be
added, certain species of Podophrya. With the exception of E. flavicans, it is further-
more the only representative of the genus Epistylis in which the pedicle is perforated
by a central canal ; in the present instance, however, this canal is continuous to the
junction of the pedicle with the body of the zooid, while in the former case it is solid
both at this point and at the axes of the divergent branches.

Epistylis balanorum, Mereschk. PL. XXXIX. FIG. 5.

Body sub-cylindrical, tapering posteriorly, about two and a half times as
long as broad, having a deep groove or constriction immediately beneath
the peristome ; the ciliary disc continued above the peristome-border as a
prominent, elevated, median, boss-like projection, having several annula-
tions around its base, and a pointed conical anterior termination ; cuticular
surface entirely smooth ; parenchyma finely granulate ; endoplast band-like,
curved ; pedicle smooth, branching in a more or less" regular dichotomous
manner, bearing but a small number of animalcules. Length of zooids
1-240".

HAB. — Fresh water : White Sea, attached to the embryos of Balanus sp.

As indicated by Mereschkowsky,f the zooids of this species correspond closely in
the remarkable modification of the ciliary disc with the fresh-water Epistylis umbili-
cata of Claparede and Lachmann.

Supplementary Species.

The three following species, included in Pritchard's 'Infusoria' without any
notification of their original authorship, are too indistinctly defined for present
identification.

Epistylis barba.

Bodies of animalcules ovate, oblong, white ; pedicle branching dichoto-
mously, longitudinally and regularly striate. Dimensions unrecorded.
HAB. — Fresh water, on the larvae of aquatic insects.

Epistylis euchlora.

Bodies of animalcules oblong, slightly expanded anteriorly, containing
green granules ; pedicle smooth, branching dichotomously. Altitude 1-13".
HAB. — Fresh water, on Planorbis cornea, Berlin.

Epistylis pavonina.

Bodies of animalcules very large, helmet-shaped, elongate anteriorly ;
pedicle very high, longitudinally striate, dichotomously branched. Altitude
of entire colony 1-3". HAB. — Fresh water, Berlin.

The Epistylis botrytis of Ehrenberg, " Bodies exceedingly minute, not exceeding
the 1-2400", clustered at the extremity of a simple hyaline pedicle," is undoubtedly
identical with the Anthophysa vegetans of Fresenius, and Codosiga pulcherrimum of

* 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxxix., 1877.

t " Protozoendes Nordlichen Russland," ' Archiv f. Mikroskopischer Anatomic, 'Bd. xvi., 1878.

7 10 ORDER PERITRICHA.

Professor H. James-Clark. The Epistylis vegetans of the same writer : " Bodies
very small, ovate, disposed in clusters on a branched yellow pedicle ; length
1-3450", is synonymous with Anthophysa Muelleri" A third species, Ehrenberg's
Epistylis arabica — " Small, oval, campanulate, pedicle but little branched, smooth
and hyaline; entire height 1-140"; hab. Red Sea" — is probably a Flagellate form
belonging to the genus Codosiga, nearly related to the author's C. pyriformis. The
Epistylis minutus of R. Greeff,* whose colony-stocks resemble in miniature those
of Ep. flavicans, but the length of whose bodies does not exceed 1-3000", is appa-
rently referable to the genus Dendromonas.

GENUS XI. OPERCULARIA, Stein.

Animalcules ovate, pyriform, or campanulate, seated at the extremities
of a rigid, more or less branching, tree-like pedicle or zoodendrium ; ciliary
disc attached to one side of the wide oral entrance or vestibulum, isolated
and usually elevated to a considerable distance above the margin of the
peristome, after the manner of an operculum ; a delicate hyaline collarlike
membrane taking its origin from the inner border of the peristome, usually
protruded with and forming a sort of under-lip to the ciliary disc ; other
gtructural details as in Epistylis or Vorticella.

The rigid, mostly ramifying pedicle of the members of this genus corresponds
essentially with that of Epistylis, but the animalcules attached to the summits of
the branches are readily distinguished by the more complex structure of their oral
or peristomal region. In the lateral attachment and operculum-like elevation of the
ciliary disc the zooids of Opercularia also considerably resemble those of the genus
Lagenophrys, while the membranous collar-like expansion, forming as it were a
supplementary under-lip to the ciliary region, represented feebly in Lagenophrys, may
certainly be accepted as homologous with the more complex funnel-like membrane
of the genus Spirochona, An additional feature which serves to indicate the affinity
of Opercularia with Lagenophrys is the usually more hardened texture of the cuticular
membrane, which in many instances is indurated to such an extent as to remain as
a distinct chitinous shell after the decomposition of the soft interior. These two
genera thus prepare a passage to the distinct shell-producing or loricate Vorticellan
types Cothurnia and Vaginicola.

When first instituted by Stein, the presence of two sorts of zooids, as occurs
frequently in the genus Zoothamnium, was included among the points for diagnosis ;
more recent investigation has, however, demonstrated that the supposed secondary
zooids were merely parasitic or commensal Acinetce. All the species of Opercularia
so far discovered are inhabitants of fresh water, and are for the most part met with
attached to various aquatic insects and Entomostraca.

Opercularia nutans, Ehr. sp. PL. XXXIX. FIGS. 22 AND 23.

Bodies ovate or attenuate fusiform, about two and a half times as long
as broad, tapering towards each extremity, the anterior end the wider,
the posterior one often transversely plicate; ciliary disc considerably
elevated above the margin of the peristome, bearing two circlets of
cilia ; membranous collar largely developed, obliquely set ; endoplast band-
like, curved ; pedicle tree-like, slender, branching profusely and dichoto-
mously, attaining a considerable proportionate altitude, distinctly annulate

* ' Wiegmann's Archiv,' Bd. xxxvii., 1871.

GENUS OPERCULARIA. 71 1

transversely. Length of bodies 1-430" ; height of the entire polypidom,
1-24" to 1-9".

HAB. — Fresh water, on aquatic plants and animals ; colonies including
a large number of zooids, which assume a nodding or pendent position
with relation to their stalks at the time of contraction.

This species is described by Ehrenberg under the title of Epistylis nutans, being
rightly referred to its present position by Stein. Its large, handsome, symmetrical
tree-like colonies attain an altitude and luxuriance of growth unequalled by any
other representative of the genus, and among which it is more eminently distinguished
on account of the singular and sudden nodding action displayed by the zooids
when disturbed, in place of the more ordinary phenomena of contraction. In a less
conspicuous degree a like property is possessed by Opercularia berberina. As with
the last-named species, the cuticular surface of the animalcules is considerably
indurated, in proof of which it may be mentioned that the author has on several
occasions seen the isolated cuticular investments left as empty vase-shaped trans-
parent sheaths after their detachment from the pedicle, and the complete dissolution
of the previously enclosed protoplasm. Among the figures of this species given
by Ehrenberg (PL XXXIX. Fig. 23) he delineates one animalcule having attached
to its side what he interprets to be a lateral bud, but which more probably represents
the conjugation of a migrant zooid with an ordinary sedentary unit.

Opercularia articulata, Ehr. PL. XXXIX. FIGS. 24-26.

Bodies elongate-ovate, or fusiform, truncate at each extremity; peri-
stome-border not thickened, but forming a simple terminal edge, with
often a few longitudinal plications ; remaining cuticular surface smooth
and soft, parenchyma usually densely granular posteriorly; ciliary disc
greatly elevated, bearing three circlets of cilia, membranous collar con-
spicuous ; endoplast horseshoe-shaped, transversely placed ; pedicle variously
but usually profusely and dichotomously branched, often delicately striate
in a longitudinal direction, exhibiting at remote distances more or less
distinct transverse articulations. Length of extended zooids 1-324" to
1-96", average 1-192"; altitude of tree-like colony 1-72" to 1-48."

HAB. — Fresh water, on Dytiscus marginalis and other aquatic Coleop-
tera.

The very remarkable diversity exhibited in the sizes of the zooids of this species
might be expected to pertain to stocks collected from widely separated localities.
According to Stein, however, they may be met with in separate colonies upon the
same Coleopterous hosts. An almost equal amount of variation would appear
to obtain in the build and comparative lengths of the ramifications of the pedicle ;
in some neither the main shaft nor the associated branches equal more than one-
half of the length of an extended zooid, while in other colonies the extended
zooids are as proportionately small, or even smaller, with reference to their attenu-
ately branched supporting stem.

Opercularia berberina, Linn. sp. PL. XXXIX. FIG. 27.

Bodies elongate, subcylindrical, slightly contracted at the two ex-
tremities, two and a half times longer than broad ; peristome obsolete ;
ciliary disc bearing a single circlet of cilia, protrusible but a short distance
beyond. the margin of the peristome ; membranous collar small, not easily

7 1 2 ORDER PERITRICHA .

defined ; vestibular cleft capacious, produced backwards through one-half
the length of the body ; cuticular surface membranous, transversely striate ;
contractile vesicle located near the termination of the vestibulum ; endo-
plast ovate, or slightly elongate ; pedicle irregular, dichotomously branched,
its ramuscles curved outwards, and supporting the animalcules at various
heights, presenting transverse lines or joints at variable distances, no con-
spicuous longitudinal striae. Length of bodies 1-190".

HAB. — Fresh water, on various aquatic insects ; zooids in the state of
contraction assuming a pendent posture.

The tree-like colonies of this species exhibit as wide a range of variation in their
external contour as is reported of Opercularia articulata, but the pedicle throughout
all these deviations presents a similar unequal and non-corymbose formula of growth.
The cuticular surface is reported by Stein to be considerably indurated, and to
remain, as observed by the author of O. nutans, as a transparent shell after the entire
disintegration of the previously enclosed parenchyma. This animalcule is synonymous
with the Epistylis berberiformis of Ehrenberg and the Hydra and Vorticella berberina
respectively of the ' Natursystem ' and ' Sy sterna Naturae,' ed. xii., of Linnaeus.

Opercularia Lichtensteinii, Stein. PL. XXXIX. FIG. 20.

Bodies short, subcylindrical or barrel-shaped, their length not equal-
ling double the width, slightly narrower at each extremity, the anterior
one longitudinally plicate when contracted ; ciliary disc slightly elevated
above the peristome, bearing a single circlet of cilia ; membranous collar
conspicuous, notched, or crenulate ; endoplast short, oval or completely
round ; pedicle sparingly branched, short, exceedingly thick, not equalling
the height of the extended zooids, longitudinally striate, and exhibiting
prominent transverse rugae, dividing close to its point of attachment, the
ramifications increasing in width towards their juncture with the bodies
of the zooids, and at which point they equal or exceed one-half of the
diameter of these latter. Length of bodies 1-190".

HAB. — Fresh water, on various aquatic Crustacea and Mollusca ; colony-
stocks including but a few animalcules.

The short, thick, wrinkled, sparsely dividing stem of this type closely resembles
that of Epistylis Steiniiy but is wanting in the conspicuous central canal that
characterizes that species.

Opercularia stenostoma, Stein. PL. XXXIX. FIG. 17.

Bodies elongate-pyriform or fusiform, widest in advance of the median
line, strongly contracted and almost stalk-like posteriorly; peristome-
border and ciliary disc very narrow, the latter bearing a single circlet of
cilia ; membranous collar inconspicuous, appearing only as an annular ridge
above the edge of the peristome ; endoplast long, horseshoe-shaped ;
pedicle relatively small, rigid, dichotomously divided, bearing but from four
to six animalcules, striate longitudinally and obscurely wrinkled in a
transverse direction, the secondary branches so short that the zooids are

GENUS OPERCULARIA. 713

closely approximated and appear to be attached in a sub-sessile manner.
Length of extended zooids 1-200".

HAB. — Fresh water, on the crustacean Asellus aquaticus.

In the absence of any figure of this species given by Stein, the illustration of
the same form accompanying D'Udekem's account of the animalcule as obtained
by him on Asellus aquaticus in the neighbourhood of Brussels, is herewith reproduced.
It is at the same time desirable to remark that while in D'Udekem's examples as
here figured the length of the extended zooids agrees with that given in the above
diagnosis, Stein attributes to them one of the 1-900" only, and that of 1-360" to
the entire colony-stock.

Opercularia microstoma, Stein. PL. XXXIX. FIG. 16.

Bodies irregularly pyriform, constricted behind the middle line, and
thence tapering towards the posterior extremity, about one and a half
times as long as broad; peristome and ciliary disc exceedingly narrow,
the last-named structure but slightly elevated ; membranous collar obliquely
set, presenting a tongue-like aspect ; endoplast curved, hamate ; pedicle
very short, its entire height not equalling that of a single extended zooid,
the ramifications comparatively slender, usually marked by thickly set
annular constrictions, which render it more or less crooked or knotty,
but sometimes entirely smooth. Greatest length of bodies 1-280".

HAB. — Fresh water, attached to the limbs of various Entomostraca ;
colonies including but few animalcules.

Stein remarks that this species, in both the form of the zooids and in the growth
and proportionate size of the pedicle, presents a strong resemblance to Opercularia
stenostoma, from which, however, it may be distinguished by its larger size, thicker
proportions, and more conspicuously developed hyaline collar. While the colonies
more usually include two or four zooids only, instances are cited in which about
twenty were observed grouped upon a single pedicle ; this last-named structure, not-
withstanding its branched condition, did not exceed the relative height quoted in
the foregoing diagnosis. The author has recently, January 1878, obtained small
colonies of this animalcule in company with Cothurnia astaci attached to the Ento-
mostracon Canthocamptus minutus taken from a roadside pond near Acton. The
pedicle in all the examples examined was completely smooth, while the cuticular
surface, under a magnification of eight hundred diameters, was shown to be finely
striate transversely.

Opercularia cylindrata, Wrz. PL. XXXIX. FIG. 21.

Bodies elongate, cylindrical, slightly tapering posteriorly, truncate
anteriorly, about two and a half times as long as broad ; peristome-border
scarcely differentiated, not dilated : ciliary disc very slightly elevated ;
vestibular cleft spacious, produced backward to a distance of one-third of
the length of the body ; cuticular surface finely and closely striate trans-
versely; endoplast elongate, band-like, longitudinally disposed; pedicle
tall, with subequally long, slightly curved, secondary branches, closely
striate transversely throughout its entire length, its main stem coloured
brown, colonies including numerous individuals. Length of bodies 1-500".

HAB. — Fresh water, on Cyclops quadricornis.

714 ORDER PERITRICHA.

This species is distinguished by its discoverer, A. Wrzesniowski,* from O. ber-
berina, which it most nearly approaches, by the abruptly truncate non-contracted
anterior border, by the closely striate pedicle, and by the less considerable develop-
ment of the vestibular cleft ; the endoplast is likewise much more elongate.

Opercularia hospes, From. sp. PL. XXXIX. FIGS. 9-11.

Bodies clavate, about two and a half times as long as broad, the peri-
stome-border widest, the posterior end attenuate ; ciliary disc large, mode-
rately elevated ; membranous collar conspicuous, obliquely set ; the whole
surface of the body covered with minute fibrillae, which, whether belonging
to the organism or of a parasitic nature, has yet to be determined ; pedicle
stout, cylindrical, punctate. Length of bodies 1-200".

HAB. — Fresh water.

This species is founded upon the type described by Fromentel t under the title of
Epistylis hospes, but which, as is shown by both his drawings and description, is a
true- Opercularia. The membranous collar, as represented by him in outline, he takes
for the vestibular bristle of an ordinary Epistylis bent round upon itself. The
singular fibrillate structures with which the surface of the body is invested are
regarded by Fromentel as possibly constituted of minute parasitic growths, but their
extreme abundance and equal distribution in every specimen examined scarcely
supports his view. Each distinct nbrilla is characterized as hair-like, with a globular
head, but the general aspect conveyed by Fromentel's figures, here reproduced, is
that of a froth-like exudation, or it may be a layer of trichocysts. It is to be
regretted that no details are given as to habitat, the proportions and form of growth
of the pedicle, or whether its ramifications support a large or small number of zooids.
The small portion of this element figured exhibits a remarkable punctate character.

Sub-Family II. VAGINTCOLINA.

Animalcules excreting and inhabiting indurated sheaths or loricse.

GENUS XII. VAGINICOLA, Lamarck.

Animalcules elongate-subcylindrical, enclosed singly or in pairs within
an indurated vase-shaped sheath or lorica, to the bottom of which they are
affixed directly, or by means of a short pedicle ; lorica erect, attached by
its posterior margin to the selected fulcrum of support, in a sessile
manner, or through the medium of an exceedingly short, rudimentary, rigid
pedicle ; oral and ciliary system as in Vorticella ; increasing by longitudinal
fission or gemmation ; in the former instance the zooids temporarily occupy-
ing the same domicile. Inhabiting salt and fresh water.

The genus Vaginicola, since the date of its first institution by Lamarck and further
extension at the hands of Ehrenberg, Dujardin, Stein, Claparede and Lachmann, and
other more recent writers, has become so unwieldy in point of numbers, that its
subdivision into a plurality of generic groups, each possessing well-marked structural
characteristics, has been decided on and will materially assist the student in his

* ' Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xx., 1870.
t ' Etudes sur les Microzoaires,' Paris, 1876.

GENUS VAGINICOLA. 715

identification of the numerous species. Ehrenberg's primary separation of the
stalked from the sessile types under the title of Cothurnia, while not assented to
by many recent authorities, and formerly deprecated by the author,* may, it has
been decided upon, after fuller investigation, be conveniently retained. From
among the sessile series, or ordinary Vaginicoltz, may be further eliminated for
independent generic distinction the Vaginicola decumbens of Ehrenberg and several
other species corresponding with that type in the decumbent or adnate attachment
of the lorica recently described by De Fromentel, and upon which group as a whole
the title of Platycola is here conferred. A similar distinction may with justice also
be allotted to the Vaginicola valvata of Dr. Strethill Wright, with its remarkable
door-like valve, and to which are now added two other species, the three being
collated under the new generic name of Thuricola. Lastly, among the erect and
stalked Cothurnitz are found several forms agreeing with each other, but distin-
guished from the more normal species by the possession of an attached operculum ;
upon these it is proposed to confer the new generic name of Pyxicola.

The considerable number of animalcules retained in the genus Vaginicola as here
defined are readily distinguished by their simple erect loricse, whose bases are
attached immediately to the chosen fulcrum of support without the intermedium of
a separate and distinct pedicle, and which possess, furthermore, no accessory hinged
valve or operculum-like stopper as a safeguard to the entrance to their domicile.
In many types varieties occur in which the posterior extremity tapers off to such an
extent as almost to present the aspect of such a distinct pedicle, but it will be
found on closer examination, that it never actually assumes, as in the genus
Cothumia, the character of such an independent structure. De Fromentel f has
proposed a partial subdivision of this genus, which while according in some respects
with the author's system, yields other features that do not recommend themselves for
adoption. His genus Vaginicola is thus made to include only the decumbent or adnate
V. (Platycola} decumbens and its allies, all the rest, either stalked or sessile, being
referred to the genus Cothurnia, which he again divides into three subordinate or
subgeneric sections, reserving the title of Cothurnia proper for the stalked forms,
Planicola for the stalkless ones, and that of Stylocola for certain types in which the
animalcule is attached posteriorly to the wall of the lorica through the intermedium
of several stylate processes. This last subgeneric group is here advanced to the
position of a new and distinct genus ; the author, however, is unable to concur with
the proposed substitution of the title of Planicola for those species universally
accepted as typical representatives of the genus Vaginicola. No distinction is
suggested by De Fromentel for the types included in the two genera Pyxicola and
Thuricola.

Vaginicola crystallina, Ehr. PL. XL. FIG. i.

Lorica transparent, subcylindrical or elongate pitcher-shaped, rounded at
the attached posterior extremity, slightly contracted towards the anterior
border, about three times as long as broad ; body of animalcule projecting,
when fully extended, for one-third of its total length beyond the orifice of the
lorica ; the parenchyma usually enclosing numerous bright green chlorophyll-
granules ; endoplast elongate, band-like. Length of lorica 1-210".

HAB. — Fresh water, on Lemna, Myriophyllum, and other water-plants.

In common with other species of the genus Vaginicola and its allies, two animal-
cules produced through the longitudinal fission of one originally single zooid, are
frequently, as delineated in the accompanying illustration, found occupying the same
sheath or lorica.

* 'Monthly Microscopical Journal,' vol. i., 1869. .f 'Etudes sur les Microzoaires,' 1876.

716 ORDER PERITRICHA.

Vaginicola tincta, Ehr.

Lorica urceolate or subcylindrical, brownish-yellow, about twice as
long as broad, rounded or truncate posteriorly, the anterior border
everted; body hyaline, not much exsert. Length of lorica 1-280" to
1-150". HAB. — Fresh water, on Zygnema and other water-plants.

The author has recently received examples of this species from Loch Lundie,
Dundee, through Mr. John Hood, its companions on the same weed being Platycola
longicollis, Thuricola valvata, Codosiga umbellata, and other sedentary Flagellata.
According to their age the loricse varied in colour from perfectly transparent through
yellow to dark chestnut. The larger size included in the foregoing diagnosis repre-
sented the more normal dimensions of the lorica, whose contour might be appro-
priately compared to that of a short test-tube.

Vaginicola grandis, Perty.

Lorica subcylindrical, but of slightly undulating outline, narrower and
truncate posteriorly, the anterior margin slightly everted, nearly three
times as long as broad ; animalcule projecting but little beyond the orifice
of the lorica ; parenchyma enclosing green chlorophyll-granules. Length
of lorica 1-108". HAB. — Fresh water, on aquatic plants.

Stein, and Claparede and Lachmann consider this form to be identical with
Vaginicola, crystallina, but its considerably larger size, diiferent contour of the
anterior margin of the lorica, and the fact, according to Perty's figure, that the
animalcule when outstretched projects but slightly beyond its protective sheath, seem
to warrant its retention as a distinct species.

Vaginicola gigantea, D'Udk. sp.

Lorica transparent, subcylindrical, two and a half times as long as
broad, rounded, and slightly inflated posteriorly, the anterior border even
or somewhat irregular ; animalcule extending beyond the anterior margin
of the lorica for fully half its length ; peristome widely dilated and
revolute ; ciliary disc much elevated and having a thickened border ;
vestibular cleft extending backwards to a considerable distance ; vestibular
seta largely developed ; contractile vesicle situated close to the entrance to
the vestibule ; endoplast exceedingly long, cord-like, more or less con-
volute, extending through the greater portion of the length of the body.
Length of lorica 1-125". HAB. — Pond water.

This form, which is described by D'Udekem* under the title of Cothurnia gigantea,
most closely resembles Vaginicola grandis, but is distinguished from that type by the
rounded instead of truncate posterior extremity of the lorica and by the great dis-
tance to which the body is protruded beyond its anterior border.

Vaginicola globosa, D'Udk. sp. PL. XL. FIG. 3.

Lorica scarcely one and a half times as long as broad, dilated and
subglobose centrally, bluntly pointed posteriorly, narrowing and slightly

* 'Infusoires de la Belgique,' 1864.

GENUS VAGINICOLA. 717

prolonged towards the somewhat uneven anterior border; the extended
body projecting but slightly beyond the aperture of the lorica ; peristome-
border thickened ; ciliary disc obliquely elevated ; endoplast cord-like,
convolute. Dimensions unrecorded. HAB. — Fresh water.
Figured and described by D'Udekem as a species of Cothurnia.

Vaginicola ingenita, From. sp.

Lorica very short, only one and a half times as long as broad, narrow
at the aperture, inflated posteriorly ; body transparent, granular, very
elastic, extending considerably beyond the aperture of the lorica. Length
of lorica 1-400". HAB. — Fresh water.

Identical with the Planicola ingenita of De Fromentel.*

Vaginicola attenuata, From. sp.

Lorica subcylindrical, sharply and abruptly attenuate towards its point
of attachment, truncate and not everted anteriorly, about twice as long
as broad ; animalcule small, protruding but little beyond the aperture of
the lorica, urn-shaped when contracted. Length of lorica 1-300".

HAB. — Fresh water.

Vaginicola vestita, From. sp.

Lorica vase-shaped, twice as long as broad, the anterior border narrow,
bulging posteriorly, but rapidly tapering again towards its point of attach-
ment, the upper two-thirds transparent, colourless, the lower one brown and
opaque ; animalcule trumpet-shaped when extended, protruding to a mode-
rate extent beyond the aperture of the lorica. Length of lorica 1-400".

HAB. — Fresh water.

The two colours of the lorica of this animalcule, referred to the genus Planicola
by De Fromentel, form a very remarkable feature. Its discoverer does not, how-
ever, say whether many specimens were encountered exhibiting a like peculiarity,
a circumstance which leaves it open to conjecture whether the upper transparent
portion of the lorica may not possibly represent a repaired portion or even the
newly formed lorica of a young individual built up from the fragmentary basal portion
of a deserted test In other respects the aspect of this type coincides closely with
that of D'Udekem's Vaginicola globosa.

Vaginicola inclinata, From. sp.

Lorica transparent, subcylindrical, rounded and widest posteriorly,
nearly three times as long as broad, never fixed perpendicularly to, but
deviating at a sharp angle from its base of attachment ; body transparent,
granular, trumpet-shaped, extending for nearly half its length beyond the
aperture of the lorica. Length of lorica 1-500". HAB. — Fresh water.

Included by De Fromentel in the genus Planicola.

* ' Etudes sur les Microzoaires,' 1876.

718 ORDER PERITRICHA,

GENUS XIII. THURICOLA, S.K.
(Greek, thuris, door ; colo, to inhabit.)

Animalcules and loricae as in Vaginicola, but the latter structure having
hinged to its inner wall a simple or complex valve-like apparatus, which
closes obliquely after the manner of a door when the animalcule contracts,
and protects it from intrusion from without. Inhabiting salt and fresh
water.

This new genus is established by the author upon the Vaginicola valvata of Dr.
Strethill Wright, to which is added the Cothurnia operculata of Gruber and a fresh-
water type, apparently identical with the Vorticella folliculata of Miiller, found by
recent investigation to exhibit a remarkable modification of the characteristic door-
like valve.

Thuricola valvata, Wright sp. PL. XL. FIGS. 4 AND 5.

Lorica subcylindrical, truncate posteriorly, four or five times as long
as broad, bearing internally at some distance from its aperture an oval
valve-like organ, which, falling down when the animalcule retreats, effectually
protects it from intrusion from without ; body hyaline, capable of extension
for about one-third of its total length beyond the orifice of the lorica.
Length of lorica 1-200". HAB. — Salt and fresh water.

This animalcule, originally described by Dr. Strethill Wright under the title of
Vaginicola valvata, was discovered by him in sea-water and is usually recorded as a
strictly marine form. D'Udekem * reports, however, a species from fresh water that
is apparently indistinguishable from this type, and an identical animalcule has been
frequently observed by the author. In accordance with the description of its
original discoverer, the characteristic valvular apparatus is of an ovate shape and
horny consistence, developed within and covered by a fleshy plate, which is attached
by one edge and continuous with a pellicle that lined the entire cavity of the lorica.
This fleshy plate alone forms the hinge-joint to the horny valve, and is consequently
separated and absent from the dead and empty tubes. In specimens recently
received from Mr. John Hood of Dundee, the presence of a lining membrane in con-
nection with the operculum as above reported, and similar to that figured by Gruber
of Thuricola operculata, was found to exist. Excepting for the presence of this
peculiar valve, the animalcule and its tube in the present species closely approxi-
mates in form and size the fresh-water Vaginicola crystallina.

Thuricola folliculata, Mull. sp. PL. XL. FIGS. 6-8.

Lorica subcylindrical, rounded and slightly widest posteriorly, about
four times as long as broad ; valvular apparatus consisting of a flattened
comb-like fascicle of horny setae, which opens outwards or closes down on
the retracted animalcule in the same manner as the single valve-like
structure in T. valvata; the body projecting, when extended, for nearly
or quite one-half its length beyond the aperture of the lorica ; peristome
expanding, revolute ; parenchyma frequently enclosing chlorophyll-granules.
Length of lorica 1-200" to 1-150". HAB. — Salt and fresh water.

* ' Infusoires de la Belgique,' 1864.

GENUS THURICOLA— COTHURNI A. 719

Seen from either a front or dorsal aspect, and viewed with insufficient magnifying
power, the complex mechanism which here takes the place of the simple valve of the
form last described, presents the appearance, indicated at PI. XL. Fig. 6, of two
oppositely opposed arcuate cusps. It is under these conditions that the author has
been able to establish its identity with the Vorticella folliculata of O. F. Mullen
Viewed again in profile, its aspect corresponds so closely with that of the ovate
valve of Thuricola valvata that it is scarcely to be distinguished from that form.
Examined with a power of 600 or 800 diameters, the comb-like character of the
valve is, as shown at PL XL. Figs. 7 and 8, very clearly demonstrated, and when
once recognized, may be easily defined with a much lower power. The author has
obtained this type abundantly in pond water in the neighbourhood of London, and
has likewise received it through Mr. Thomas Bolton from Stourbridge, Worcester-
shire. An animalcule in no essential points distinguishable from the fresh-water
species has been obtained by the author in salt water at Bognor, Sussex.

Thuricola operculata, Gruber sp. PL. XL. FIGS. 13-15.

Lorica sessile, transparent, subcylindrical, slightly constricted towards
the anterior border, over three times as long as broad, one side of the
anterior margin developed greatly in advance of the other ; valve or oper-
culum circular, attached to the lorica by a delicate membranous ligament,
which is continued down one side and joined to the base of the animalcule's
body ; animalcule slender, subcylindrical, projecting when fully extended
for nearly half its length beyond the aperture of the lorica, its cuticular
surface finely striate ; transversely attached basally to the lorica through the
medium of a distinct footstalk. Dimensions and habitat unrecorded.

This species differs essentially from Thuricola valvata in the uneven or emarginate
contour of the anterior border of the lorica, in the usually more slender proportions
and greater extensility of the enclosed animalcule, and in its mode of fixation
through the medium of a separate footstalk to its excreted domicile. The data
recorded by Gruber relating to the opercular structure, in describing this animalcule
under the title of Cothumia operculata? are of high interest, and are thus sum-
marized : " In empty loricse the operculum is always open, so that its closure must
be due to the contraction of the animal. There is, in fact, attached to its under
surface, one end of a delicate cuticular membrane (PI. XL. Figs. 14 and 15, r /),
bent longitudinally into a long cylinder, and with its other end embracing the
proximal extremity of the animal. When the latter retracts, the membrane is pulled
upon and the operculum closed. The membrane is so delicate that under ordinary
circumstances all that can be seen of it are its edges, which look like two
delicate threads passing from the base of the animal to the operculum." It will
probably be found that a similar delicate membrane connects the operculum with
the body and fulfils a similar function in the preceding species.

GENUS XIV. COTHURNIA, Ehrenberg.

Loricae erect, attached posteriorly to their basis of support through the
medium of a conspicuously developed pedicle ; animalcules, as in Vagi-
nicola, either adherent in a sessile manner to the posterior extremity of
the lorica, or fixed to the same by a continuation from without of the
external supporting pedicle. Inhabiting salt and fresh water.

* 'Zeit. Wiss. Zool.,' Bd. xxxiii., p. 439, 1879. (Translation in 'Journal of Royal Micro-
scopical Society," April 1880.)

720 ORDER PERITRICHA.

Cothurnia imberbis, Ehr. PL. XL. FIGS. 9 AND 10.

Lorica ovate, about twice as long as broad, narrowest anteriorly, its
margin not everted, transparent when young, assuming a yellow tinge when
old ; pedicle shorter than the lorica, sometimes curved ; body of extended
animalcule projecting but little beyond the margin of the lorica ; endoplast
linear, slightly curved. Length of lorica 1-288" to 1-240".

HAB. — Fresh water, on Entomostraca and aquatic plants.

This, the most familiar representative species of the genus Cothurnia^ is frequently
found in great abundance on the Entomostracon Cyclops quadricornis. It is not,
however, confined to an animal host, being as often met with upon the thread-like
filaments of various species of Conferva. The pedicle is occasionally so short as to
present a mere button-like aspect. Sometimes it is continued through the wall of
the lorica, thus imparting to the animalcule a doubly pedicellate character.

Cothurnia maritima, Ehr.

Lorica ovate, transparent, one and a half times as long as broad, slightly
inflated posteriorly ; pedicle much shorter than the lorica ; parenchyma
hyaline, whitish. Length of sheath 1-570" to 1-350".

HAB. — Salt water, on algae, &c.

Excepting for its smaller size, this species closely resembles C. imberbis. It was
observed by the author of specimens developed in great abundance in a jar contain-
ing decomposing algae, at St. Heliers, Jersey, that the cuticular surface as viewed
with a j-inch objective was distinctly striate in a transverse direction.

Cothurnia havniensis, Ehr. PL. XL. FIG. 19.

Lorica wineglass-shaped, transparent, truncate and widest anteriorly,
scarcely one and a half times as long as broad ; pedicle slender, three or
four times the length of the hyaline sheath ; body whitish. Length of
sheath, without stalk, 1-280". HAB. — Salt water.

This species was obtained by Ehrenberg in company with Acineta Lyngbyei on
Ceramium and Sertularian zoophytes at Copenhagen. According to his figures
given, here reproduced, the animalcule presents a much more broadly ovate form than
obtains among all ordinary Cotkurnice, and occupies only the distal portion of the
lorica. Excepting for the presence of the anterior fringe of cilia, the general contour
of both the lorica and contained zooid corresponds with that of a long-stalked
Acineta, and as an imperfectly observed representative of which genus the author
is much inclined to regard it.

Cothurnia Sieboldii, Stein. PL. XL. FIGS. 24 AND 25.

Lorica gibbously urceolate, strongly compressed in front, dilated pos-
teriorly, more especially on the dorsal aspect ; the two frontal angles
extended upwards and outwards, and again curving inwards at their
extremities, so as to resemble two horns ; walls of the sheath hyaline when
young, turning from yellow to deep rusty brown with age ; pedicle colour-
less, short, thick, curved, and transversely wrinkled, much thickened at its
point of juncture with the sheath ; body of animalcule small in comparison

GENUS COTHURNIA. 721

with the size of the lorica, but little exsert beyond its margin when
extended. Length of large-sized lorica 1-190".

HAB. — Fresh water, on various Entomostraca, but more especially abun-
dant on the branchial appendages of the fresh-water crayfish, Astacus
fluviatilis.

Cothurnia astaci, Stein. PL. XL. FIG. 26.

Lorica urceolate, about twice as long as broad, the posterior half
rounded and slightly ventricose, narrowest and contracted behind the
slightly everted and even anterior border ; colourless or pale yellow ;
pedicle thick, short, slightly curved, transversely plicate ; animalcule
slender, subcylindrical, protruding some distance beyond the margin of
the sheath. Length of lorica 1-288".

HAB. — Fresh water, on Astacus fluviatilis and various Entomostraca.

During a fatal epidemic among the fresh-water cray-fish of Lombardy and
Venetia in the year 1863, it is reported by Ninni* that the dying Crustacea were
completely infested with an Infusorium, referable to the genus Vaginicola, probably
identical with the present species, its abnormal development on the branchial
appendages apparently producing the death of the crustacean through asphyxia.

Cothurnia curva, Stein. PL. XL. FIG. 27.

Lorica gibbous, ventricose posteriorly, curved to such an extent ante-
riorly as to impart to the aperture an oblique direction ; transparent when
young, but of a dull rusty-red colour in the adult state ; animalcule agreeing
in form with C. astaci and C. Sieboldii but not protruding to so great a
distance beyond the orifice of the lorica. Length of lorica 1-360".

HAB. — Fresh water, attached to various Entomostraca.

Stein rather doubts whether this species may not be considered as a distorted
variety of C. astaci. The author, however, is inclined to regard it as an independent
type, having found it abundantly at different times upon Canthocamptus minutus in
the neighbourhood of London. In all instances the curved or gibbous contour of the
lorica was constant, and the animalcules were never observed to protrude themselves
to that distance beyond the orifice of the aperture which has been described of
C. astaci. On one occasion a lorica was met with in which numerous spore-like
bodies, probably representing the reproductive gemmules of the former occupant, were
found attached by a short peduncle or funiculus to the bottom of its internal cavity.
A species so closely resembling the present form that the same diagnosis serves for
its description, has been obtained by Professor Boeck attached to marine Ento-
mostraca on the coast of Norway. Claparede and Lachmann have proposed to
distinguish it by the title of Cothurnia recurva, but there does not appear to be
sufficient reason for regarding it as otherwise than a salt-water variety of the species
just described. The contour of the lorica in this type is perhaps slightly more
slender, and the curvature of the neck scarcely so strongly pronounced.

Cothurnia nodosa, C. & L.

Lorica transparent, subcylindrical, somewhat narrowed anteriorly, about
twice as long as broad, frequently with one or more symmetrical transverse

* ' Atti del Imp. Reg. Istituto Veneto,' 1864.
VOL. II. c

722 ORDER PERITRICHA.

annular constrictions across the centre ; pedicle varying in its proportions
from one-quarter to the same length as the lorica, produced usually to some
distance within the lorica, having frequently a button-like node or boss
immediately beneath its point of juncture with the lorica, this node, however,
often produced inside the lorica, or supplemented by a second boss-like
enlargement where the pedicle joins the animalcule's body. Length 1-570".
HAB. — Salt water, on algae, &c.

This form was first met with by the author at Bognor, Sussex, in the autumn
of the year 1872, and has been since obtained in great abundance from the Menai
Straits, North Wales, and has been also remitted by Mr. John Hood from Dundee.
The pedicle in most examples examined was produced a considerable way inside
the lorica, and the single boss developed at the base of this internal prolongation.
The surface of the animalcule, as seen with a magnifying power of 200 diameters,
was also distinctly striate transversely, after the manner of Cothurnia marina which
it closely resembles. Among the several modifications of this type reported by
C. Mereschkowsky from the White Sea, the one possessing a slender, rigid footstalk
equal in height to the lorica which it supports, is figured under the name of
C. nodosa var. longipes.

Cothurnia compressa, C. & L. PL. XL. FIGS. 17 AND 18.

Lorica transparent, ovate, three times as long as broad, compressed
anteriorly, so as to leave a long, narrow, slit-like terminal aperture ;
pedicle exceedingly short, supplemented by a boss-like inflation within the
interior of the carapace, to which the animalcule is attached. Length of
lorica 1-178". HAB. — Salt water, on seaweeds and Bryozoa.

The author met with this well-marked variety attached to seaweeds and
zoophytes gathered in the vicinity of St. Peter's Port, Guernsey, in the autumn of
the year 1871. The animalcules were in all instances a pale amber colour, the
anterior or peristome region being widely dilated, so as to give it a trumpet shape
when expanded, while the cilia were very long and powerful. Claparede and
Lachmann's figures, here reproduced, represent the species in its contracted or semi-
contracted conditions only.

Cothurnia ovata, Duj.

Lorica transparent, ovate, very short, scarcely one and a half times
as long as broad, truncate and slightly dilated at the aperture ; pedicle
short and stout. Animalcules trumpet-shaped when expanded, protrusible
to a considerable distance beyond the. aperture of the lorica. Length of
lorica 1-200".

HAB. — Fresh water, on Conferva and other aquatic plants.

This species may be distinguished from Cothurnia imberbis, with which it is most
likely to be confounded, by the much shorter and more truncate contour of the
lorica and by the capacity of the contained zooid to protrude to a longer distance
beyond the orifice of its domicile.

Cothurnia patula, From. PL. XL. FIGS. 20 AND 21.
Lorica transparent, cup-shaped, very short and broad, the breadth
slightly exceeding the length, the anterior margin conspicuously everted ;
pedicle short and stout ; animalcules trumpet-shaped when expanded, pro-

GENUS COTHURNI A. 723

truding for half their length beyond the aperture of the lorica. Length of
lorica 1-450". HAB. — Fresh water, on Confervas.

Cothurnia elongata, From.

Lorica subcylindrical, slightly widest posteriorly, twice as long as broad,
rugose or granular, colour yellow ; pedicle exceedingly short, inconspicuous.
Animalcule elongate, subcylindrical, possessing two contractile vesicles, both
of which are situated towards the centre of the body, in the rear of the
pharyngeal cleft, not protruding far beyond the aperture of the lorica.
Length of lorica 1-400". HAB. — Fresh water.

The two contractile vesicles reported by De Fromentel,* if persistent — though
their number and position indicated is so abnormal that the author is inclined to
regard them as simple parenchymal vacuoles— distinguish this form in a marked
manner from all the ordinary members of the Vaginicolina. A more important and
reliable character of distinction is, perhaps, aiforded by the granular consistence of
the lorica.

Cothurnia spissa, From.

Lorica tumbler-shaped, slightly narrower and rounded posteriorly, the
anterior margin nearly as wide as the lorica is long, the sides straight, not
everted at the anterior margin ; pedicle short and stout ; animalcule vase-
shaped ; the peristomal region much constricted, not protruding when
extended beyond the margin of the lorica. Length of lorica 1-400".

HAB. — Fresh water, on Conferva.

The lorica in this species closely resembles that of C. patula, but may be dis-
tinguished from that variety by its straight lateral borders, as also by the small
capacity of extension possessed by the contained animalcule.

Cothurnia irregularis, S. K.

Lorica transparent, subcylindrical, one and a half times as long as
broad, the anterior margin not everted, the posterior region slightly inflated,
irregularly notched ; pedicle curved, produced a short distance within the
lorica ; animalcule obconical, narrowest posteriorly, very wide at the
anterior margin, protruding when extended but little beyond the aperture
of the lorica. Length 1-450". HAB. — Fresh water.

This form in no way agreeing with the C. nodosa of Claparede and Lachmann, to
which De Fromentel has with doubt referred it, it has become incumbent on the
author to propose a new specific title for its distinction.

Cothurnia Cohnii, S. K. PL. XL. FIG. 22.

Lorica elongate-ovate, subcylindrical, about three times as long as
broad, rounded and inflated posteriorly, narrowest and attenuate towards
the anterior extremity, the frontal margin abruptly truncate, the aperture
circular, the posterior third ornamented with four or five conspicuous
annular furrows, the remaining portion perfectly smooth ; pedicle short
and stout, not exceeding one-quarter the length of the lorica; enclosed
* ' Etudes sur les Microzoaires,' 1876.

S 2

724 ORDER PERITRICHA.

zooid attached to the lorica through the medium of a short, transversely
annulate, elastic pedicle, which in the extended state nearly equals the
body of the animalcule in height ; peristome-border very prominent and
massive, exserted but a short distance beyond the margin of the lorica.
Height of lorica 1-400".
HAB. — Salt water.

The non-conformance of this type with the Cothurnia pupa of Eichwald, as
tentatively suggested by Cohn in his description of this elegant type,* has necessi-
tated the substitution of the new title, associated with his own name, that is here
proposed. That it is perfectly distinct from the last-named species is at once
demonstrated on reference to the original figures and description of that form in
Eichwald's ' Infusorienkunde Russlands,' reproduced at PI. XL. Fig. 23. In the
present species the grooves or annulations are confined entirely to the posterior
portion of the lorica, which as a whole presents an elongate subcylindrical contour.
In Eichwald's C. pupa, on the other hand, the general contour is almost evenly
ovate, three prominent transverse annulations being distributed at equal distances
throughout its length. The lorica of the present species, as described by its dis-
coverer, is remarkable for its brilliant coloration, the margins, as in certain Crypto-
monads, reflecting a brilliant scarlet hue, while a paler roseate tint suffuses the
intervening area.

Cothurnia pupa, Eichw. PL. XL. FIG. 23.

Lorica symmetrically ovate, widest centrally, tapering evenly towards
each extremity, about twice as long as broad, sometimes slightly constricted
beneath the terminal aperture ; surface ornamented with three raised trans-
verse annuli, one encircling the centre of the lorica, the two others at equal
distances between the centre annulus and the anterior and posterior
extremities ; colour brown ; pedicle short, about one-fourth the length of
the lorica. Dimensions unrecorded. HAB. — Fresh water.

Cothurnia gracilis, S. K. PL. XL. FIG. 12.

Lorica attenuate, curved, three and a half times as long as broad, widest
and rounded posteriorly, gradually tapering towards the narrow and curved
anterior region, the anterior aperture minute, truncate, and not everted ;
pedicle short, thick, and transversely rugose ; animalcule, when contracted,
ovate, with a nipple-like anterior projection. Length of lorica 1-250".

HAB. — Salt water, on minute Crustacea.

The author obtained a single example only of this species, in February 1878, at St.
Heliers, Jersey, attached to a thoracic appendage of the crustacean Nebalia bipes,
having there associated with it as messmates Spirochona Nebalii, previously described,
and the singular Trematode Saccobdella Nebalice. of Professor C. J. Van Beneden.
The exceedingly attenuate and graceful contour of the lorica of this species readily
distinguishes it from all previously recorded types, its curvature, however, to some
extent, approximating it to the Cothurnia curva of F. Stein. The animalcule was
not observed in its expanded state, the crustacean to which it was attached having
unfortunately been immersed in a preservative fluid prior to its discovery.

* ' Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xvi., 1866.

GENUS PYXICOLA. 725

Cothurnia arenata, Mereschk.

Lorica transparent, subcylindrical, slightly curved, about twice as high
as broad, its walls irregularly undulate ; the anterior aperture even, neither
constricted nor everted, obliquely set ; supporting pedicle stout, one-third
the height of the lorica, dilated at its base or point of attachment ; enclosed
animalcule elongate, pyriform, contracted and attenuate posteriorly, attached
to the bottom of the lorica without any intermediate prolongation of the
pedicle. Height of lorica 1-200".

HAB. — Salt water : White Sea (Mereschkowsky).

Cothurnia pontica, Mereschk. PL. XL. FIG. n.

Lorica urceolate or pitcher-shaped, about twice as long as broad, the
two sides of the anterior margin elevated and expanded in a lip-like
manner, terminating posteriorly in an exceedingly short boss-like pedicle,
which is supplemented by a somewhat longer interiorly produced hollow
conical peduncle, to which the body of the animalcule is attached ; the
posterior half of the lorica ornamented by four or five strongly developed
transverse annulations. Animalcule not observed in the living state.
Length of lorica 0*0171 millim. HAB. — Salt water: Black Sea (Meresch.).

This species is figured and described by M. C. Mereschkowsky in the ' Annals
and Magazine of Natural History' for March 1881. .

GENUS XV. PYXICOLA, S. K.

(La.t., £yxis, box; colo> to inhabit.)

Animalcules attached posteriorly within a corneous lorica, the lorica
erect and usually mounted on a pedicle ; a discoidal corneous operculum,
similar in consistence to the lorica, developed beneath the border of the
peristome, and which, when the zooid is retracted, effectually closes the
orifice of the lorica.

Excepting for the presence of the corneous operculum, which closes down and
protects the animalcule from interference from without, the representatives of this
genus agree entirely with those of Cothurnia. So long, indeed, as a single represen-
tative only of this type was known, it seemed desirable to retain it in that genus ;
recent investigation has, however, elicited the existence of so many additional oper-
culiferous forms, that it has become desirable to institute a new generic group for
their reception.

Pyxicola operculigera, S. K. PL. XL. FIG. 39.

Lorica transparent when young, dark chestnut brown when old, ovate,
slightly gibbous, about twice as long as broad, posteriorly attenuate, the
anterior margin slightly oblique ; pedicle transparent, slender, straight, often
twice the length of the lorica; enclosed animalcule subcylindrical, pro-
truding to a considerable length beyond the aperture of the lorica, bear-
ing beneath the peristome a circular opercular-like disc similar in colour

726 ORDER PERITRICHA .

and consistence to the substance of the lorica. Length of the lorica
1-400". HAB. — Brackish water.

This species was originally figured and described by the author in the ' Monthly
Microscopical Journal' for May ist, 1869, under the title of Cothurnia operculigera.
The specimens furnishing this description were obtained from the brackish waters of
the Victoria Docks, in connection with one of the periodical excursions of the
Quekett Microscopical Club, and were first submitted to the author's notice by Mr.
Walter Reeves, of the Royal Microscopical Society. The most distinctive feature of
this form is afforded by the great relative length of the pedicle, which, with the
exception of P. socialis, is equalled by no other known species. An essential dis-
tinction subsisting between the present species and the last named type is afforded
by the contour of their respective loricae, which is in the one case perfectly smooth
and in the other transversely annulate, to which it may be added that the pedicle,
while more often curved in Pyxicola sorialis, is in P. operculigera invariably recti-
linear. The species now under notice was found abundantly on the polyparies of
Condylophora lacustris, as also on other aquatic plants and animals growing upon the
timber in the docks ; in one instance as many as four individuals were met with
attached to the lorica of a larger and closely allied member of the same family
group, i. e. Vaginicola crystallina ; this particular example is figured in the original
description and illustration above quoted.

Pyxicola pyxidiformis, D'Udk. sp. PL. XL. FIG. 41.

Lorica symmetrical, subfusiform, widest and angular in the centre, taper-
ing towards the two extremities, each of which is truncate, the posterior one
being the narrower ; the front margin bearing a disc-shaped operculum
which closes the aperture when the animalcule is retracted ; pedicle
transparent, about one-fourth the height of the lorica; the lorica and
operculum in the mature zooids opaque, rich chestnut brown, transparent
when young. Animalcule when extended protruding to some distance
beyond the aperture of the lorica. Height of lorica 1-150''.

HAB. — Fresh water.

D'Udekem* remarks that the operculum of this interesting form, described by him
under the title of Cothurnia pyxidiformis^ is apparently attached to the body of the
animalcule, but at the same time, as shown in the accompanying illustration, figures
it as though fastened in a hinge-like manner to the front margin of the lorica.

Pyxicola pusilla, S. K.

Lorica urceolate, curved and slightly gibbous, the anterior aperture
obliquely set, narrowest anteriorly, rounded and inflated posteriorly,
about twice as long as broad ; colour dark chestnut brown when old,
transparent when young ; pedicle very short, permanently transparent,
averaging one-tenth of the length of the entire lorica. Contained animal-
cule regularly conical, widest anteriorly and tapering gradually towards
its attachment to the lorica, which is effected through the medium of a
short boss-like protuberance ; the operculum conspicuous only in the older
individuals, elevated to but a short distance beyond the aperture of the
lorica ; endoplast band-like, spirally curved. Length of lorica 1-500".

HAB. — Fresh water, among Lemnce.

* 'Infusoires de la Belgique/ 1864.

GENUS PYXICOLA. 727

Pyxicola afflnis, S. K. PL. XL. FIGS. 28 AND 29.

Lorica urceolate, slightly curved, gibbously inflated, about twice as long as
broad, rounded and widest posteriorly, slightly constricted beneath the narrow
and obliquely truncate distal aperture ; colour deep chestnut brown when
old, transparent when young, amber-colour at an intermediate stage ; pedicle
always transparent, varying from one-third to nearly one-half the height of
the lorica. Contained animalcule protruding but little beyond the orifice of
the lorica, thick and subcylindrical, tapering posteriorly, attached to the
bottom of the lorica without the intermedium of a boss -like prominence ;
operculum massive and conspicuous. Length of lorica 1-300".

HAB. — Pond and marsh water.

The contour of the lorica in this species so nearly resembles that of Pyxicola
pusilla that the author was at first disposed to regard it as a mere variety of that form.
Having, however, obtained examples from several remote localities, namely, Wands-
worth Common, London ; Leicestershire, and the Channel Islands, that in all in-
stances possessed the characters given in the above diagnosis, its claim for separate
specific recognition can scarcely be set aside. The distinction between these at first
sight apparently closely allied forms is moreover found on closer examination to be
considerable. The dimensions of the lorica of the present type are, in the first instance,
very much longer, added to which may be cited the much greater relative length of
the pedicle, the thicker and more cylindrical contour of the enclosed animalcule, and
the direct and more simple character of its attachment to its domicile. The species
appears to be of solitary habits, only two or three examples being found on each
occasion where it was met with. Like Pyxicola pusilla, it was usually obtained
attached to Lemna or other aquatic plants, its companion in the Channel Islands
habitat being the interesting biflagellate type Eutreptia viridis.

Pyxicola furcifer, Hutton sp.

Lorica ovate, narrower and slightly constricted anteriorly, its aperture
obliquely set ; pedicle short, one-sixth of the length of the lorica. Animal-
cule transparent, subcylindrical, dilated anteriorly, attached directly to the
bottom of the lorica ; ciliary disc apparently bearing at its lateral angles
four robust bifurcating stylate cilia; operculum conspicuous only in the
adult individuals ; colour of lorica, operculum, and basis of attachment
of the pedicle deep chestnut brown, the pedicle transparent. Height of
lorica 1-500". HAB. — Fresh water : New Zealand.

This species, figured and described by Professor F. W. Hutton, of Otago, New
Zealand, in the ' Journal of the Royal Microscopical Society' for May 1878, under the
title of Cothurnia furcifer, finds its natural place in the present genus. The contour
and proportions of the lorica agree most nearly with those of Pyxicola pusilla, but the
contained animalcule, according to the figure and description quoted, presents in the
adornment of its ciliary disc an altogether anomalous characteristic. In no known
representative of the Vorticellidae has the presence of similar stylate appendages in
this region been recorded. A somewhat similar optical aspect to that represented
in Professor Hutton's woodcut is, however, frequently produced through the inter-
section at their lateral edges of the inner and outer peristomal wreaths of cilia, and it
is not improbable that a like interpretation is applicable in the present instance.

728 ORDER PERITRICHA.

Pyxicola socialis, Gruber sp. PL. XL. FIGS. 16, 30, AND 31.

Lorica ovate or urceolate, produced anteriorly into a narrower distally
expanded neck, the central region ornamented with three distinct grooves
or annulations ; pedicle equalling or slightly exceeding the length of the
lorica, straight or irregularly curved ; body extending but slightly beyond
the aperture of the lorica ; the oral side of the peristome bearing a circular
indurated operculum of the same colour and consistence as the lorica.
Length of lorica 1-250".

HAB. — Salt water, social ; colour of lorica dark brown in adult
examples, yellow or colourless in younger specimens.

This species, originally described by Dr. August Gruber,* in company with
Thuricola operculata and other interesting forms, under the title of Cothurnia socialis,
is appropriately named in allusion to its eminently gregarious habits. While isolated
specimens are met with, it more usually happens that a single primary lorica, as
shown at PI. XL. Fig. 30, gives support to three or four more, producing in the
aggregate a pseudo-compound colony-stock remarkably suggestive of the compound
" polythecia " of the flagellate genera Dinobryon, Stylobryon, and Polywca, described
in the preceding volume. In other words, as Dr. Gruber suggests, " the species
affords an example of the least modified form of a compound animal or ' stock ' ; the
connection of the various persona? forming it being of the loosest description."
According to its discoverer, there is developed in this type, on the inner edge of the
peristome on the oral side, a very delicate funnel-shaped or collar-like membrane, iden-
tical, he says, with the structure usually described as a bristle-like cilium (sole de Lach-
tnann). This membrane, which is evidently homologous with the collar-like mem-
brane of Operciilaria, bounds the mouth externally as an outwardly sloping wall,
being highest immediately opposite this orifice, and gradually sloping away on either
side. Particles of food hurled against it by the action of the cilia of the disc are at
once swept into the oral entrance, while those missing it are whirled away from the
animal.

It appears desirable to identify with Pyxicola socialis the somewhat nondescript
organism, half Rotifer and half Infusorium, figured and described by Mr. John
Davies in the 'Journal of the Royal Microscopical Society' for October 1879, under
the title of Cothurnia corrugata. The contour of the lorica agrees entirely with that
of Gruber's species, except that two cusp-like processes would appear, in accordance
with the figures given, to be usually developed at the posterior extremity. Mr. Davies'
summary of the morphological characters of the contained animalcule, as shown in
the following quotation, serve no other purpose beyond that of revealing a surprising
lack of acquaintance with even the most elementary details of the organic beings
among which he would allocate the subject of his discovery : —

"The cephalic extremity of the animal (Rotifer) when extended is of an oval form, hardly as
long or as broad as the aperture of the lorica. The head is furnished with two strong cilia, or more
properly speaking, setae, which are forked to about half their length, a follicle being observed at their
base. The thread-like appendages (setae ?) move with a spasmodic jerk, and are very irregular in
their action. They may be probably covered with a glutinous matter, as they are frequently observed
to bend towards the central vortex, possibly to deposit particles that have adhered to them. At the
end of the thoracic tube is what seemed to be a mastax. In this part of the animal are situated
two contractile vesicles, one on either side of the jaws. No eyes were apparent. Towards the
posterior extremity is a light coloured and rather large vessel, which I believe to be the anus. The
footstalk has, I believe, a central cord as in Vorticella, but I am not certain on this point. It does
not at any time contract its stalk ; in fact, it exhibits no motion in this part of its organization."

A serious analysis of the foregoing diagnosis will not be attempted, but it may
be suggested that the so-called forked setae or thread-like appendages therein

!Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxxiii., 1879.

GENUS PACHYTROCHA. 729

mentioned may be accepted, as in the case of P. furcifer, as representing the
intersecting peripheral elements of the ordinary Vorticellidan ciliary wreath, and
which are f->r the most part alone distinctly visible during energetic action.
From the tine of Leeuwenhoek, who in the year 1675 first described a bell-ani-
malcule or Vorticella as possessing two little anteriorly developed horns,* similar
horn-like or setose appendages have been ascribed to various members of the same
family group. This misinterpretation, while excusable to the early investigators
labouring with simple lenses of their own manufacture, is however scarcely expected
of an F.R.M.S. of the nineteenth century, working, as Mr. Davies admits, with a
T^-inch objective, and having the accumulated experiences of two centuries to fall
back upon.

Pyxicola socialis has been recently reported by Mereschkowsky \ from the
Solowetz Islands, in the White Sea.

Pyxicola Carter!, S. K. PL. XL. FIG. 40.

Lorica elongate subcylindrical, three times as long as broad, rounded
and attached posteriorly by a very short or rudimentary pedicle, constricted
at a little distance below the even, slightly oblique, anterior margin, the
side walls more or less irregularly undulate ; animalcule attenuate, project-
ing when extended to a considerable distance beyond the orifice of the
lorica ; the operculum borne on the infero-lateral surface of a conspicuous
conical protuberance that projects from beneath the peristome-border ;
colour of lorica and operculum yellow or dark brown according to age,
animalcule transparent. Dimensions unrecorded.

HAB. — Fresh water : Bombay (H. J. C.) ; Victoria Regia House,
Botanic Gardens, Regent's Park (S. K.).

The above name was first conferred upon an infusorial form included in some MS.
notes upon the Infusoria of Bombay, kindly placed at the author's disposal by Mr.
Carter, and which has been since personally obtained developed in great abundance
on Conferva and other water-plants growing in the comparatively hot water of the
Victoria Regia House in the Regent's Park Botanic Gardens. The irregular undula-
tion of the walls of the lorica readily distinguishes it from all of the species previously
enumerated. In his original drawing, Mr. Carter has represented the anal aperture
as debouching at the apex of the conical projection which supports the operculum ;
but in this particular the author anticipates there has been some misconception,
so essential a deviation from the typical histological formula being scarcely probable.

GENUS XVI. PACHYTROCHA, S. K.
(Greek, pachus, thick ; troches, wheel.)

Animalcules loricate, corresponding in all points with those of Pyxicola,
with the exception that a fleshy pad is developed in place of the indurated
operculum distinctive of that genus.

Pachytrocha cothurnoides, S. K. PL. XL. FIG. 32.

Lorica transparent, urceolate, somewhat gibbous, widest and inflated
posteriorly, the anterior aperture somewhat obliquely set, about twice as
long as broad, mounted on a pedicle which rarely equals one-quarter of its

* See Vol. I. pp. 4 and 8. t 'Annals of Natural History,' March 1881.

730 ORDER PERITRICHA.

total length ; animalcule subcylindrical, projecting but little beyond the
orifice of the lorica ; fleshy operculum thick and tumid, enclosing, in common
with the body sarcode, numerous refringent corpuscles. Length of lorica
1-500". HAB. — Pond water.

This remarkable type was obtained by the author in June 1880 attached to leaves
of Myriophyllum taken from the lake in Kew Gardens. The singular swelling
beneath the peristome which occupies the place of the horny operculum in Pyxicola,
and acts as effectually as a cork or plug to bar the aperture of the lorica from intru-
sion when the animalcule is retracted, may be appropriately compared to that
abnormally swollen condition of the human throat known as goitre. Excepting for
its perfect transparency, the lorica of this species corresponds essentially in both size
and contour with that of Pyxicola pusilla.

GENUS XVII. STYLOCOLA, De Fromentel.

Loricae and enclosed animalcules as in Vaginicola, but the zooids
attached to the bottom of their loricae through the medium of numerous
stylate processes.

Two representatives of this genus only have so far been recorded, both of which
inhabit fresh water. It is desirable that the nature of the posterior attachment of
the animalcules to their loricse should be further investigated, as the brief description
and figures given by De Fromentel,* leave room for a doubt whether or not these so-
called stylate processes may not prove to be the longitudinal striation of an internal
pedicle, or the rays of an adhesive organ as in Spirochona, Should De Fromentel's
interpretation prove correct, the posterior stylate appendages would appear to
correspond with the posterior setae of Astylozoon rather than with the short pedicle
of many ordinary Vaginicolince.

Stylocola striata, From. PL. XL. FIG. 2.

Lorica short, vase-shaped, the breadth almost equalling the length,
slightly inflated posteriorly, the anterior margin slightly everted, united
with its basis of support by a boss or button-like protuberance ; animalcule
attenuate, cylindrical, very elastic, protruding when expanded beyond the
margin of the lorica to a distance equal to one-half of its total length,
attached to the bottom of the lorica by a fan-shaped expansion of numerous
long, stout, stylate processes ; the cuticular surface coarsely striate trans-
versely. Length of lorica 1-450". HAB. — Fresh water.

Stylocola ampulla, From.

Lorica transparent, sessile, subcylindrical, attenuate, rather over twice
as long as broad, slightly inflated posteriorly, contracted towards the
anterior end ; animalcule cylindrical, attached to the bottom of the lorica
by a few short, stout, stylate processes, not protruding far beyond the
aperture of the lorica ; surface smooth. Length of lorica 1-400".

HAB. — Fresh water.

* ' Etudes sur les Microzoaires,' 1876.

GENUS PLA TYCO LA. 7 3 I

GENUS XVIII. PLATYCOLA, S. K.
(Greek, platus, flat ; colere, to inhabit.)

Animalcules as in Vaginicola, but the lorica always decumbent and
attached throughout one entire side to its fulcrum of support.

To the type form of this genus, the Vaginicola decumbens of Ehrenberg, a large
number of species recently figured and described by De Fromentel are here added ;
all of these are included by him, in his ' Microzoaires,' as representatives of the
typical genus Vaginicola.

Platycola decumbens, Ehr. sp. PL. XL. FIGS. 33 AND 34.

Lorica decumbent, oval, depressed, transparent when young, becoming
dark brown when older, not developed anteriorly in a neck-like manner;
body hyaline, considerably exserted during extension, and projected at
right angles to the part contained within the sheath. Length of lorica
1-280". HAB. — Fresh water, on various aquatic plants and animals.

The author has not unfrequently found small specimens of the pond-snail
Planorbis sp., whose shells were almost entirely encrusted with the loricae of this
abundant species. As in Vaginicola and Cothurtiia, two zooids are often developed
by longitudinal fission within the same domicile.

Platycola mollis, From. sp.

Lorica decumbent, bottle-shaped, three times as long as broad, some-
what wrinkled and irregular posteriorly, produced anteriorly towards one
side into a short and straight, abruptly truncate, not everted neck ; ani-
malcule very contractile, yellow, scarcely reaching, when extended, to the
aperture of its lorica ; integument finely punctate. Length of lorica, with
neck, 1-300". HAB. — Fresh water.

Platycola dilatata, From. sp. PL. XL. FIG. 43.

Lorica broadly bottle-shaped, the breadth almost equalling the total
length, bordered round its side of attachment with a frill-like extension of
its substance ; neck short, narrow, constricted at its base ; colour pale
yellow ; animalcule large, subcylindrical, broadest anteriorly, transparent,
extensile to a considerable distance beyond the aperture of the lorica ;
parenchyma finely granulate. Length of entire lorica 1-300".

HAB. — Fresh water.

Platycola regularis, From. sp.

Lorica smooth, elliptical, about one and a half times as long as broad,
ventricose, developed anteriorly into a short, narrow, and somewhat dilated
neck, which is usually bent slightly upwards, colour pale yellow ; animalcules
when contracted ovate, transparent, not yet observed in their extended
state. Length of lorica 1-350". HAB.— Fresh water.

732 ORDER PERITRICHA.

Platycola tmncata, From. sp.

Lorica oval, rounded at the base, truncate anteriorly, having no pro-
jecting neck, occasionally with a few transverse plicae, the margin of attach-
ment slightly expanded in a frill-like manner ; colour yellow ; animal-
cule transparent, subcylindrical, posteriorly attenuate, extensile to a
considerable distance beyond the margin of the lorica. Length of lorica,
1-400". HAB. — Fresh water.

Platycola striata, From. sp. PL. XL. FIG. 42.

Lorica colourless, elliptical, ventricose, one and a half times as long as
broad, developed anteriorly into a very short truncate neck, the surface of
the inflated body portion ornamented with numerous, usually eight, trans-
verse striae, distributed at even distances between the neck and the posterior
extremity, the surface of attachment supplemented with a narrow frill-like
lamina ; animalcule cylindrical, transparent, surface finely punctate. Length
of lorica 1-350". HAB. — Freshwater.

Platycola gracilis, From. sp.

Lorica transparent, subcylindrical, about twice as long as broad, rounded
and slightly inflated posteriorly, aperture obliquely truncate, not taking the
form of a separate neck ; surface of attachment expanding in a frill-like
manner ; animalcule trumpet-shaped, massive, transparent ; vestibular
bristle very conspicuous. Length of lorica 1-400".

HAB. — Fresh water.

De Fromentel mentions that the vestibular bristle, in addition to being con-
spicuous, is often reflexed in a ring-like form, and so figures it ; from his description
and illustration given it would appear that the animalcule possesses a distinct mem-
branous lip or collar as occurs in the genera Opercularia and Lagenophrys.

Platycola longicollis, S. K. PL. XL. FIG. 35.

Lorica smooth, evenly ovate, depressed, prolonged at its anterior
extremity into a long, narrow, obliquely elevated neck, whose length equals
that of one-third of the ovate body portion ; colour varying from yellow
to chestnut-brown ; the animalcule projecting when extended to a distance
equal to the length of the neck of the lorica from the aperture of that
structure. Length of entire lorica 1-200". HAB. — Fresh water.

This species, as first figured, without an independent specific description, by
De Fromentel,* is referred by him to the Vaginicola decumbent of Ehrenberg, from
which type, however, it may be at once distinguished by its long obliquely directed
neck. Examples of this species have been recently received by the author through
Mr. John Wood from the neighbourhood of Dundee. In external contour the lorica
closely resembles that of the Heterotrichous form Follicularia Boltoni previously
described. _j .

* ' Etudes sur les Microzoaires,' 1876.

GENUS LAGENOPHRYS. 733

GENUS XIX. LAGENOPHRYS, Stein.

Loricae ovate or pyriform, adnate or laterally attached, with a small,
contracted, and often valvular anterior aperture ; animalcules irregularly
ovate, occupying the anterior region of the lorica, and adherent throughout
the peristomal region to the margin of the aperture ; ciliary disc laterally
attached, separately stalked as in Opercularia, protrusible to a consider-
able distance beyond the aperture of the lorica, the free edges of the peri-
stome usually produced around the base of the extended disc in the form
of a membranous frill or collar ; the remainder of the oral system, endoplast,
and contractile vesicle as in all ordinary Vorticellidae. Increasing within
the cavity of the lorica by oblique fission or gemmation. Inhabiting fresh
water ; mostly ectoparasitic or commensal.

The animalcules of this genus exhibit in the lateral attachment of their ciliary
disc and membranous collar a close affinity with the genera Opercularia and Pyxidium.
Lagenophrys may further be accepted as connecting the loricate and illoricate Vorti-
cellan groups, the more indurated cuticle of certain representatives of the genus
Opercularia, as already shown, frequently remaining in a loricate form after the decay
of the internal body-substance. The species so far discovered are all inhabitants
of fresh water, and are to be found attached to Entomostraca and other aquatic
animals.

Lagenophrys vaginicola, Stein. PL. XL. FIGS. 36-38.

Lorica elongate, cordate, having at its broader anterior end a circular
aperture with two even, semicircular, prominent, valvular or lip-like pro-
cesses, which are raised or depressed when the enclosed animalcule protrudes
or retracts itself ; enclosed animalcule ovate, adherent by its narrow peri-
stome to the orifice of the lorica. Length of lorica 1-380", greatest width
1-640". HAB. — Fresh water, attached to Canthocamptus minutus.

The author has frequently obtained this species attached to the caudal hairs
of the above-named Entomostracon.

Lagenophrys ampulla, Stein. PL. XL. FIGS. 44-46.

Lorica depressed, nearly orbicular, resembling a plano-convex circular
lens, but having an anterior, projecting, everted rim in front of the oral
aperture, this projecting rim ornamented with a moniliform pattern ; animal-
cule similar in form to the sheath. Diameter of sheath 1-480" to 1-360".

HAB. — Fresh water, attached to the branchial appendages of Gammarus
pulex and Asellus aquations.

Lagenophrys nassa, Stein. PL. XL. FIG. 47.

Lorica nearly spherical, plano-convex as seen in profile and emarginate
at the anterior or oral extremity; mouth of the lorica prolonged at its
margin into a subcylindrical, flexible, longitudinally plicate and toothed
lip-like extension, which, when closed on the retreat of the animal, some-

734 ORDER PERITRICHA.

what resemble in shape the mouthpiece of a clarionet. Length of lorica
1-400".

HAB. — Fresh water, attached to the leg joints of Gammarus pulex.

This species, while closely resembling the preceding in size and general con-
tour, is readily distinguished from it by the peculiar character of the lip-like ante-
rior prolongation, or free edge of the peristome-border. As remarked by Stein,
the longitudinally plicate structure of this organ exhibits a remarkable conformity
with the longitudinally plicate membrane or pharyngeal rod-fascicle of Prorodon,
Chilodon, and other Holotrichous and Hypotrichous types, and with which indeed it
is apparently homologically identical. Examples of this species associated with
Spirochona gemmipara have been recently received by the author through Mr. Thomas
Bolton.

Sub-Family III. OPHRYDINA.

Animalcules excreting and inhabiting a soft mucilaginous solitary
sheath or compound zoocytium.

GENUS XX. OPHIONELLA, S. K.

(Dim. Greek, ophis, snake.)

Animalcules solitary, elongate, highly contractile, secreting a mucila-
ginous investing sheath, to the bottom of which they are not permanently
attached ; oral system as in Vorticella and Ophrydium ; endoplast linear ;
contractile vesicle spherical, anteriorly situated.

The representatives of this genus resemble isolated stalkless zooids of the genus
Ophrydium, from which, however, they differ in not being permanently attached to
the bottom of their mucilaginous domicile in either a sessile manner or through the
medium of a pedicle. The single species so far observed is an inhabitant of fresh
water.

Ophionella picta, S. K. PL. XLI. FIGS. 22 AND 23.

Body transparent, elongate vermiform, subcylindrical, slightly inflated
posteriorly, highly elastic, protruding when expanded to a considerable
distance beyond the aperture of its sheath, the cuticular surface smooth or
finely granular. Length of extended body, 1-150".

HAB. — Fresh water, on aquatic plants.

This species was obtained by the author in some abundance in the spring
of the year 1874, its characteristic mucilaginous dwellings being constructed within
the angles formed by the filamentous branchlets of a leaf of Myriophyllum spicatum.
A single example of the same form was likewise encountered, but at the time
imperfectly observed, on Anacharis received from Mr. Thos. Bolton, of Birming-
ham, in December of the year 1872. The attitude assumed by the animalcules in
their expanded condition is very elegant, they at such times protruding nearly one-half
of their body beyond the aperture of the sheath, and throwing the extended portion
into various graceful curves. On the slightest disturbance the body is withdrawn to
the bottom of its sheath, and contracted into a small ovate mass. In demonstration
of the non-permanent character of the attachment of the animalcule to the bottom of
its domicile, an example was observed on one occasion to vacate it and to
wander off in quest probably of a more productive feeding ground. In addition to

GENUS OPHRYDIUM. 735

the similarity that subsists between the animalcules of this species and the detached
zooids of Ophrydium, a still more marked one perhaps exists between the same and
the permanently attached naked animalcules of D'Udekem's Gerdafixa previously
described.

GENUS XXI. OPHRYDIUM, Ehrenberg.

Animalcules elongate, subcylindrical, highly contractile, growing in
attached or free-floating social clusters, and exuding a common coalescent
mucilaginous investing matrix or zoocytium, within which the bodies are with-
drawn at the time of contraction, generally united to each other or to their
basis of support by a simple or branching pedicle, but occasionally sessile ;
peristome and adoral system as in the ordinary Vorticellidae ; ciliary disc
on the oral or ventral side usually greatly elevated ; contractile vesicle
spherical, subcentral, with a canal-like diverticulum, which ascends to and
surrounds the peristome; endoplast elongate, cord-like, often convolute.
Inhabiting salt and fresh water. Increasing normally by longitudinal, but
occasionally by transverse fission.

By many writers Ophrydium has been separated from the ordinary Vorticellidae,
and been made the type of a distinct family group under the title of the Ophrydina.
It is evident, however, that its distinctive feature, as represented by the common
mucilaginous matrix, may be regarded as a compound modification only of the lorica
of Vaginicola and its allies, being in conjunction with that more indurated structure
derived through a redundant development of or exudation from the hyaline cuticle.
The passage from one group to the other is moreover clearly indicated through the
newly introduced genus Ophionella, the sheath of which permanently retains the soft
and plastic consistence characteristic of the lorica of Vaginicola in its earliest or
immature condition. An essentially analogous socially constructed mucilaginous
matrix or zoocytium has been already described in connection with the several
Flagellate genera Phala?tsterium, Spongomonas, and Protcrospongia, and in the author's
opinion obtains also, with various complex modifications, throughout the entire class
of the Spongida. A further reference to this premised analogy is included in vol. i.
pp. 171 and 176.

Ophrydium versatile, Mull. sp. PL. XLI. FIGS. 1-9.

Bodies flask-shaped, ovate or globular when contracted, attenuate
when extended, usually exhibiting a slightly inflated, subfusiform central
portion, a conically pointed posterior extremity, and a cylindrical and
neck-like anterior region ; the cuticular surface finely annulate throughout
and also longitudinally plicate towards the posterior region ; vestibular fossa
very capacious, occupying the entire space between the highly elevated
ciliary disc and border of the peristome, continued into a wide ciliated
pharynx, and terminating in an elongate cesophagus, the entrance to which
is dilated and double-walled, and thence developed backwards to the centre
of the body as a narrow and, except when food is passing, scarcely
visible tube ; parenchyma coloured more or less brilliant green through the
presence of innumerable imbedded chlorophyll-granules ; zooids forming
extensive and mostly free-floating social clusters of a more or less globose

736 ORDER PERITRICHA.

form, united to each other by a slender, even, dichotomously branching,
thread-like pedicle. Length of extended bodies 1-80" to 1-35".
HAB. — Salt and fresh water.

Ophrydium versatile is a species remarkable for the very considerable dimensions
attained by its social colonies ; while the more normal size of these colonial aggre-
gates may be compared with that of a walnut, it not unfrequently happens that old
established stocks present an almost spherical contour with a diameter of no less than
five inches. The number of united zooids in these larger colonies must be reckoned
at least by millions, and when drifting upon the surface of the water they bear so
close a resemblance to similarly shaped detached masses of the fresh-water sponge,
Spongilla lacustris, that without a nearer examination they may easily be mistaken
for that organism. Although a type that has attracted the notice of all the earlier
and most modern writers — it being identical with the Vortlcella versatilis of Miiller,
and probably also the Ulva and Tremella pruniformis of Linnaeus — it is but quite
recently that an exhaustive and accurate account of its more minute anatomy has
been placed on record. This has been contributed by Professor A. Wrzesniowski
to the number of the ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxix. Heft. 3,
1877, containing the results of his investigation of Dendrocometes paradoxus and
other infusorial types already alluded to. Previously it had been represented by
the chief authorities, including even Stein, that the adjacent animalcules were quite
independent of one another, and simply immersed within or adherent posteriorly
to the peripheral layer of their common gelatinous matrix. By Fresenius, never-
theless, so long since as the year 1849, ^ was reported that an independent thread-
like stalk was produced from the posterior termination of each zooid and penetrated
nearly to the centre of this matrix, but this observation was not confirmed by sub-
sequent investigation. As now shown, however, by Wrzesniowski, such a thread-like
stalk is not only possessed by each animalcule, but all of these stalks are united in a
dichotomous manner to one another, and form in the aggregate a symmetrical
bifurcating thread-like pedicle comparable to that of an Epistylis, and produced in a
like manner by the repeated longitudinal fission and centrifugal outgrowth of the'
primary zooids. The common gelatinous matrix within which the whole of this
branching pedicle is immersed has also been more generally represented as forming a
single, continuous, homogeneous investment, but the authority quoted has shown that
by treatment with osmic acid this element is resolvable into distinct subcylindrical
areas, each representing the portion formed by a separate individual, and having
at its latest produced or distal region an ovate cavity, resembling that of the lorica
of a Cothurnia or Vaginicola ; it is within this cavity that the animalcule is found in its
contracted state after treatment with the reagent named. Illustrations of this matrix
thus treated and of the branching pedicle, reproduced from Wrzesniowski's delineations,
will be found in Figs. 4 and 8 of the accompanying plate. In addition to the more
ordinary green form of this animalcule Wrzesniowski obtained another in which
the colouring matter was entirely absent. Upon this he has proposed to confer the
title of Ophrydium versatile var. hyalinum, retaining that of O. versatile var. viride
for the more normal coloured type. This hyaline variety is shown, however, to differ
in so many other more important points that the author is inclined to regard it as
a distinct species identical probably with the form next described. Among the chief
distinctions cited may be mentioned more especially the considerably smaller size of
the zooids, which never attain to one-half of that of the coloured ones, and are only
found inhabiting small attached gelatinous matrices of but a few millimetres' diameter,
while their supporting stalks are simple or but slightly branched. It was further
observed that the stalk in the green variety, immediately beneath its juncture with
the body, exhibited frequently three or four prominent annulations, which were
never detected in the hyaline form. The phenomena attending the establish-
ment of new colonies by these respective varieties or types present likewise
an important divergence. The zooids separated from the parent mass of the
coloured form attached themselves freely to whatever substance with which they

GENUS OPHRYDIUM. 737

come in contact, often selecting as a nucleus for their new establishment the
minute gas-bubbles on the surface of the water, and from which were developed
the floating spheroidal clusters. In this green variety more usually, also, a
number of animalcules congregated together and assisted in the fabrication of
the common gelatinous matrix. In the hyaline type, on the other hand, a single
zooid only laid the foundation of the new colony, while the leaves of some water-
plant were invariably selected as the fulcrum of attachment

Ophrydium Eichornii, Ehr. PL. XLI. FIGS. 10-18.

Bodies attenuate, cylindrical, subfusiform and tapering posteriorly,
mounted on a slender pedicle whose length equals or exceeds that of the
extended body, and which is continuous and undivided to its basis of
attachment ; the cuticular surface finely annulate transversely, very elastic,
and enabling the animalcule to assume a variety of positions ; parenchyma
perfectly transparent and colourless ; forming attached hemispherical
gelatinous colonies of numerous closely approximated individuals, occa-
sionally dividing by transverse fission. Length of expanded zooids i-ioo"
to 1-50". HAB. — Fresh water, on Anacharis.

The author received a species corresponding with the above diagnosis, in some
quantity, growing on Anacharis, in November 1871, and also in March 1874,
from Mr. Thomas Bolton, he having collected it in the neighbourhood of Stour-
bridge, Worcestershire. At that earlier date it was proposed to distinguish this
variety by the title of Ophrydium longipes, no other representative of the genus
having so far been authentically certified to possess a pedicle which penetrated to
the basis of attachment of the common gelatinous mass. A similar feature has
nevertheless been since shown by Wrzesniowslc to obtain in O. versatile, though
in the ordinary form of that species it presents a more complex, ramifying aspect

Since formulating the foregoing diagnosis, the author has obtained access to Ehren-
berg's brief diagnosis of his Ophrydium Eichornii* which may be thus summarized : —

Animalcules elongate, hyaline, subfusiform, forming small, hemispherical, trans-
parent polyparies, with centrally radiating caudal setce, attached to Ceratophyllum and
other water-plants. Length of bodies 1-44" to 1-72".

This Ophrydium is further identified by Ehrenberg with a so-called species of Vorti-
cella, imbedded in a gelatinous matrix, described by Eichorn in the year 1838. There
can be little doubt that the so-called caudal setae of Ehrenberg's type correspond
with the characteristic pedicles of the present form, which exhibit in profile, as
shown at PL XL. Fig. 10, a similar radiating aspect, while the size, habits, and other
details, so far as recorded, agree so completely with those of the author's Ophrydium
longipes that the two must be regarded as identical and the earlier name of
O. Eichornii be retained. The author is also inclined to accept Wrzesniowski's
var. hyalinum of O. versatile as synonymous with the present species, this identity
being self-evident upon a comparison of the diagnoses of the two forms.

The colonies of Ophrydium Eichornii first received from Mr. Bolton contained
at the most about one hundred zooids, the entire hemispherical mass yielding
in its longest diameter a measurement of about the one-eightieth part of an
English inch. Still more recently, April 1881, colony-stocks of much larger
dimensions have been obtained through the same source, the finest of them
measuring no less than the one-eighth of an inch across and enclosing many
hundred animalcules. In some of the smallest colonies examined there were no
more than four enclosed zooids, each possessing a long and fully developed pedicle ;
this last named circumstance is of special importance as distinguishing it from the

* ' Bericht. der Akad. zu Berlin,' p. 191, 1853.
VOL. II.

738 ORDER PERITRICHA.

type next described. In no instances was the pedicle branched or even bifurcated,
though in some of them nearly double the length of the extended zooid. In
O. viride, as described by Wrzesniowski, the ramification of this structure is mani-
fested at a very early period, more usually on arriving at a length of one-half or
even one-quarter only of that of the animalcule's body. The plasticity of the
parenchyma and cuticle in this type would seem to exceed that of either the fore-
going or succeeding forms, such plasticity allowing the animalcules to throw
themselves into a complicated folded contour as delineated at PI. XLL Fig. nA,
The increase of this species by transverse fission — a phenomenon of rare occurrence
among the Vorticellidse — was noted on numerous occasions, the zooids so multi-
plying dividing across the centre, and the ultimately detached anterior half acquiring,
a little in advance of this line, an annular zone of locomotive cilia as in the motile
zooids of an ordinary Vorticella. In the last-named type, however, it is the whole
animalcule that becomes disconnected, while in the present instance the posterior
half is left attached to the pedicle, and developing a new contractile vesicle and
oral system, assumes the form of an ordinary zooid. In this process of subdivision
the characteristic cord-like endoplast takes its share. The detached portion
swims away in a conical form, as delineated at PI. XLI. Fig. 19, and settling down
lays the foundation of a new colony, or in some instances coalesces probably with
other sedentary animalcules to ensure the sexual rejuvenation of the species.
This last phenomenon has not, however, up to the present time been actually
observed.

As a more recent synonym of Ophrydium Eichornii must be included the type
figured and described by Dr. H. C. Evarts in the ' American Monthly Microscopical
Journal,' vol. i., 1880, under the title of Ophrydium Adce.* The colony-masses
obtained from American waters measured in diameter from one-half to two lines,
the larger examples including as many as a thousand zooids. No new data are
recorded by Dr. Evarts with reference to their structure or development.

Ophrydium sessile, S. K. PL. XLL FIGS. 19-21.

Bodies hyaline, colourless or of a slightly brownish hue, attenuate, sub-
cylindrical, truncate or tapering posteriorly, sometimes slightly inflated
centrally, attached immediately, without the medium of a peduncle, to the
fulcrum of support ; the cuticular surface finely annulate transversely ;
zooids forming small hemispherical masses of closely approximated indi-
viduals not exceeding one-eighth of an inch in diameter. Length of extended
bodies 1-80". HAB. — Fresh water, on Anacharis and other aquatic plants.

This animalcule was received by the author in November 1871, from Mr. Bolton,
in company with the species last described, and of which it was at first regarded as
the initial or immature condition. Amongst the points favouring its specific distinct-
ness from the type Ophrydium Eichornii, it may be mentioned that no examples of
this sessile form were found associated with the consignment remitted in the year
1874, and that colonies of as many as from forty or fifty to several hundred stalkless
individuals have been met with, while in the last-named type the stalks were fully
developed in clusters of as few as four zooids. There can be little doubt that this
stalkless species of Ophrydium is identical with the animalcule described and some-
what roughly delineated by Mr. H. J. Slack in his ' Marvels of Pond Life,' p. 152,
ist ed., 1 86 1, and there referred with hesitation to the genus Vaginicola. The zooids
in this instance presented, as at first observed and figured, a more evenly cylindrical
contour and a more abruptly truncate base than was exhibited by the examples
forwarded by Mr. Bolton, while the parenchyma, instead of being white and trans-
parent, was tinged a brownish hue. After being kept a day, their bodies were

See also 'Journal of the Royal Microscopical Society,' April 1 880.

ORDER HYPOTRICHA. 739

observed by Mr. Slack to become more pointed posteriorly, and to exhibit towards the
centre a fusiform dilatation as in the more normal examples examined by the author.
Quite recently, October 1881, the author has obtained luxuriant colonies of this
species attached to Myriophyllum growing in a pond in Epping Forest, visited in
connection with a field-day of the Epping Forest Naturalists' Field Club. It was
observed of examples preserved for some few days that the zooids freely abandoned
their original mucilaginous zoocytium, and, reattaching themselves independently,
were scarcely distinguishable during such isolated condition from those of Gerda
fixa, described in a previous page.

Order IV. HYPOTRICHA, Stein.

Animalcules free-swimming, mostly flattened or compressed ; loco-
motive cilia confined to the inferior or ventral surface, often variously
modified; the superior or dorsal surface usually smooth or glabrous, but
occasionally bearing a few scattered or longitudinal rows of immotile setose
cilia ; oral and anal apertures conspicuously developed, ventrally located ;
trichocysts rare.

Excepting for the very considerable augmentation of the number of genera
they contain, the several family groups of the Hypotricha embodied in the present
volume correspond substantially with those introduced by Stein in the first and
second parts of his ' Organismus,' published respectively in the years 1859 and 1867.
The only important modification of that author's scheme is accomplished through
the transference to this order from the Holotricha of the genera Loxodes and
Litonotus recently shown by Wrzesniowski to be ciliate only on their ventral
aspect, and by the" slight alteration that has necessarily been effected in the diag-
nosis of the order through the demonstration by Engelmann and other investigators
that certain Oxytrichidae bear immotile setose cilia upon their dorsal surface. These
dorsal appendages are, however, altogether distinct from those which clothe the
ventral aspect, being rigid and immotile and taking no part in either the locomotive
or prehensile functions. While in many of the more specialized genera of the
Oxytrichidae and Euplotidae the members of the Hypotricha appear to arrive, though
by an entirely different path, at an even higher structural organization than is
exhibited by any of the preceding groups, the subordination of others as embryonic
or more simple types of the order Peritricha is likewise apparent. This is more
especially evidenced in such genera as Phascolodon and Chlamydodon, and which,
excepting for their dental armature, remarkably resemble the embryonic con-
dition of the Peritrichous genus Spirochona. But a slight modification would again
be required to convert Psilotricha into a typical representative of the free-swimming
Peritrichous family Halteriidae; the earlier condition of Styloplotes appendiculatus
exhibits also a closely analogous affinity. The passage of the Hypotricha to
or from the Holotricha and Heterotricha is clearly indicated by such genera as
Chilodon, Loxodes, and Litonotus, the characteristic dental armature of the whole of
the Chlamydodontidae pointing more especially to a no very distant union with the
Holotrichous forms Prorodon and Nassula. The more specialized structure of the
higher Hypotricha receives full attention in the account given of the family Oxytri-
chidae. As typified by this highly differentiated group, the Hypotrichous order occupies
the summit of the graduated scale of Ciliate complexity, and may be said, in virtue
of the diverse modifications and functions of the appendicular organs, to claim with
relation to the preceding sections a position closely corresponding with that held by
the Insecta with reference to the lower divisions of the Arthropoda.

In accordance with our present state of knowledge, the succeeding schedule
would appear to supply the simplest key to an intelligent apprehension of the
numerous families and genera referable to the order Hypotricha.

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742 ORDER HYPOTRICHA.

Fam. I. LITONOTID-S2, S. K.

Animalcules free-swimming/ soft and flexible, lanceolate or elongate,
having a narrower and often highly elastic neck-like anterior prolongation ;
the entire ventral surface flat, finely ciliate throughout; the dorsal surface
smooth and glabrous, mostly convex ; the oral aperture ventral, a series of
larger pre-oral cilia mostly developed in advance of the oral aperture ;
pharynx unarmed ; trichocysts usually abundant.

The Litonotidae, including at present the single genus Litonotus, represents one
of the lowest groups of the Hypotricha. But for the absence of cilia on the dorsal
surface, which up to a very recent date were presumed to exist, the several species
closely resemble such simply organized Holotricha as Amphileptus and Loxophyllum,
and to which two genera they have, indeed, been previously relegated. In no other
Hypotricha have as yet the existence of trichocysts been demonstrated, and in no
other members of this order does the cuticular investment possess so great an
amount of elasticity.

GENUS I. LITONOTUS, Wrzesniowski.

Animalcules free-swimming, highly flexible, more or less elastic, of
elongate outline, the anterior extremity attenuate and neck-like, often
exceedingly prolonged ; the ventral surface flattened and ciliate throughout,
the dorsal aspect smooth and convex ; oral aperture situated at the base of
the neck-like prolongation, close to the left-hand border ; the cortical layer
usually enclosing trichocysts ; endoplasts two in number, ovate or spherical,
closely approximated and united by a cord-like commissure.

The generic title of Litonotus has been instituted by Wrzesniowski* for the
reception of those animalcules previously referred to the genus Loxophyllum, but
which he has demonstrated by more precise investigation to be ciliate only on their
lower or ventral surface. This last-named structural characteristic has necessitated
the transfer of these types from the Holotrichous to the Hypotrichous order of the
Ciliata ; at the same time they may be regarded as constituting a bond of union
between the two, their affinity with Loxophyllum and Amphileptiis on the one hand,
and through Loxodes to the more typical Hypotricha on the other, being self-
evident.

Litonotus Wrzesniowskii, S. K. PL. XLII. FIGS. 12 AND 13.

Body elongate, linear-lanceolate, the posterior extremity pointed, de-
pressed, and tail-like, produced anteriorly into a long, flat, very slender,
highly flexible and contractile neck-like portion, which is slightly dilated at
the distal end, and whose length equals that of about three-fifths of the entire
body ; oral aperture situated at the base and to the left-hand side of the
neck-like prolongation ; ventral surface of the body furrowed longitudi-
nally, the cilia short and fine, disposed in even lines along these furrows ;
the cilia fringing the neck of larger size than those clothing the ventral

* "Infusorien aus der Umgebung von Warschau," ' Zeitschrift fur Wissenschaftliche Zoologie,'
Bd. xx., 1870.

GENUS LITONOTUS. 743

surface of the body proper and tail-like region ; an even row of obliquely set
trichocysts bordering the entire left-hand margin of the neck ; contractile
vesicle single, situated towards the posterior extremity of the central body ;
endoplasts two in number, spherical, located a little in advance of the con-
tractile vesicle ; parenchyma of the central portion granulate and opaque,
that of the flattened neck and tail-like parts perfectly transparent. Length
of extended animalcule 1-75". HAB. — Pond water, among Lemna.

Wrzesniowski figures and describes this species under the title of Litonotus
folium, proposing to identify it with the Dileptus folium of Dujardin ; a reference
to the illustrations and diagnosis of that type as given by the last-named authority,
shows, however, that the two are perfectly distinct. In the present instance we have
an animalcule corresponding most closely in contour and in the extreme tenuity of
the elastic neck with the form already described under the title of Trachelocerca olor.
In the Dileptus folium of Dujardin there is no such extreme attenuation of the
anterior extremity, the granulation of the parenchyma is equally diffused from one
extremity of the animalcule to the other, and the cuticular surface is described as
nodular and presenting a reticulate aspect suggestive of the venation of a leaf, and
from which character it received its title. The relative dimensions of the two
animalcules are likewise very distinct, for while the length of Dileptus folium in its
normally extended state equals no more than six or seven times that of its greatest
diameter, the same proportions in the present species are as 12 or 13 to i. It
being clearly evident that the form now under notice cannot be held as synonymous
with Dujardin's type, it becomes necessary to find a substitute for the specific title
given by Wrzesniowski, and it is therefore proposed to confer upon it a name
associated with that of the able investigator to whom we are indebted for the true
interpretation of the structural characters of this interesting generic group.

Litonotus fasciola, Ehr. sp. PL. XLII. FIGS. 5-11.

Body linear-lanceolate, flexible but not contractile, from five to seven
times as long as broad ; the dorsal surface smooth and naked, the ventral
one longitudinally grooved or striate ; the neck-like portion scarcely equal-
ling in length one-half of the entire body, curved at its extremity towards
the right, gradually narrowing towards this region, and not sharply distin-
guished from the body by its greatly diminished diameter as in the preced-
ing species; the tail-like region short, obtusely pointed; oral aperture
situated towards the left and a little in advance of the centre of the body ;
the cilia clothing the under surface of the neck and in advance of the oral
aperture, of larger size than those on the remaining ventral surface ;
trichocysts obliquely set along the left-hand border of this region; con-
tractile vesicle single, situated near the base of the short, tail-like prolon-
gation ; endoplasts spheroidal, subcentral. Length 1-300" to 1-200".

HAB. — Pond water and vegetable infusions.

This animalcule is identical with the Amphileptus fasciola of Ehrenberg and the
Loxophyllum amphileptus of Claparede and Lachmann. In concurrence with the
two last-named authorities, the author is inclined to regard the Dileptus folium of
Dujardin as likewise synonymous with this species, while the Amphileptus fasciola
of the same writer is apparently identical with one of the two forms next described.
Its reference to the Hypotrichous order under the generic title of Litonotus was

744 ORDER HYPOTRICHA.

effected by Wrzesniowski,* in company with the foregoing and two following species.
The observation of this animalcule by so many investigators sufficiently indicates its
plentiful and cosmopolitan distribution, it being indeed one of the most familiar of
its class, and, though not social in its habits, is rarely absent from pond water con-
taining the commoner species of duckweed, such as Lemna minor or trisuka.

The author has recently, December 1878, met with examples of this species at
an earlier period of growth than has apparently been previously described, and an
attentive observation of these onwards to the assumption of their normal adult
form has yielded data of high interest closely parallel to those placed on record
at page 794 concerning the more typical Hypotrichous species Aspidisca costata.
This earlier condition of Litonotus fasciola, represented at PI. XLII. Fig. 8, was,
when first discovered, regarded as a strange and apparently undescribed in-
fusorial type. Its contour was remarkable, most closely resembling the husk or
palea of a barleycorn or some other cereal, the broader end representing the anterior,
and the pointed one the posterior extremity of the animalcule. The dorsal surface
was inflated, and with the exception of one long central and two proportionally
shorter lateral keel-like ridges, smooth and glabrous throughout. These ridges
jutted out slightly at the anterior margin, imparting to this region a dentated aspect.
A spherical contractile vesicle was conspicuous towards the posterior extremity, the
parenchyma in its immediate vicinity being slightly granular, though everywhere
else perfectly transparent ; no trace of an endoplast or nucleus could be detected
at this early period of its development. With the utmost difficulty, using a power
of 300 diameters, the flattened or somewhat concave ventral surface was discovered
to be clothed throughout with exceedingly fine, closely set, vibratile cilia, these cilia,
as time progressed, becoming longer and more distinctly visible. At the end of
about half an hour after commencing the observation of this animalcule, the first
indications of an impending metamorphosis were perceived. The body, which had
hitherto appeared to be enclosed by a rigid and, as already remarked, palea-like
dorsal shield, gradually assumed a flexible consistence, while the previously broader
and denticulate frontal border became rounded and contracted. The several linear
keel-like ridges on the dorsal surface likewise grew more obscure, and finally, with
the exception of a faint remaining trace towards the anterior extremity of the central
and longest ridge, entirely obliterated. A series of slightly larger pre-oral cilia was
now distinctly visible along the left-hand border of the anterior region, and also,
with careful manipulation of the light, the central double endoplast characteristic of
the adult representatives of the genus. At this stage of its growth, and after the
expiration of a little over one hour from the commencement of the author's investi-
gation, the animalcule presented the appearance indicated at PI. XLTI. Fig. 9 ;
the passage onwards to the fully matured specific form, involving little beyond the
greater prolongation, curvature towards the right, and increased flexibility of the
anterior or neck-like region, was completely accomplished within the succeeding
hour. It is worthy of remark that Litonotus fasciola, in its most abnormal and
earliest observed condition of development, as above described, resembles, to a
great extent, excepting for the absence of the pharyngeal armature, the adult form
of Scaphidiodon navicula, and more especially the shorter and broader varieties of
the species represented by O. F. Miiller at pi. xxvii. figs. 9-12 of his ' Animalcula
Infusoria,' under the title of Trichoda navicula. The so-called Drepanomonas dentata
of Fresenius * is apparently also identical with the immature condition of Litonotus
fasciola as just described^

Litonotus varsaviensis, Wrz. PL. XLII. FIG. 4.

Body elongate, linear, transparent, flexible but scarcely contractile, five
or six times as long as broad, rounded posteriorly and not produced into a
distinct tail-like portion, tapering gradually towards the anterior extremity,

* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xx., 1870.

f ' Beitrage zur Kenntniss Mikroskopischer Organismen,' Taf. x. figs. 25-28.

GENUS PHASCOLODON. 745

which is usually curved towards the right ; the oral aperture nearly median ;
cuticular surface striate longitudinally ; pre-oral cilia most conspicuous ;
trichocysts distributed unevenly throughout the anterior or neck-like region ;
contractile vesicles five in number, dispersed in a line along the left border
of the body ; endoplasts spheroidal, subcentral. Length 1-250".
HAB. — Fresh water.

The large number of contractile vesicles serves to distinguish this species
from L. fastiola, which in other respects it closely resembles.

Litonotus diaphanus, Wrz.

Body elongate-lanceolate, elastic and flexible, flattened, about six times
as long as broad, tapering at each extremity, the anterior one most attenuate
and neck-like, directed slightly towards the left ; parenchyma granular
throughout, food-substances permeating the neck-like region as well as the
general body portion ; the cuticular surface longitudinally striate on the
ventral aspect ; trichocysts very long and slender, distributed irregularly
throughout the cortical layer ; contractile vesicles six in number, disposed
in a line along the right-hand border ; endoplasts two in number, ovate,
united by a cord-like filament. Dimensions unrecorded.

HAB. — Fresh water.

This type is distinguished by the character of the parenchyma, which is granular
throughout, and permits the passage of food-particles into the more attenuate neck-
like portion, whereas in the preceding species it is retained within the central or
body portion only. The trichocysts are also longer and more slender, and irregularly
distributed throughout the substance of the cortex. Wrzesniowski has regarded
these two characters of the parenchyma and trichocysts as of sufficient importance
for the institution on this animalcule of a separate subgenus, which he proposes to
distinguish by the title of Hemiophrys.

Fam. II. CHLAMYDODONTIDJE, S. K.

Animalcules free-swimming, ovate, with a convex dorsal and flattened
ventral surface ; the cuticle elastic or indurated ; the ventral surface more
or less completely clothed with fine vibratile cilia ; the oral aperture opening
on the ventral surface, followed by a tubular pharynx, the walls of which
are strengthened by a cylindrical fascicle of corneous rods or a simple
corneous tube; no stylate appendage or fascicle of caudal setae at the
posterior extremity.

The members of this family group, which corresponds with the Chlamydodonta
of Stein, as characterized in the second but not the first volume of his ' Organismus,'
are to be distinguished from those of the following family or Dysteriidae by the
entire absence of the caudal style or fascicle of setae at the posterior extremity.
Otherwise, and more especially with regard to the character of pharyngeal armature,
the two groups are closely related.

GENUS I. PHASCOLODON, Stein.

Animalcules free-swimming, persistent in form, truncate in front, rounded
or pointed posteriorly ; the dorsal region convex ; the ventral surface plane,

746 ORDER HYPOTRICHA.

widest anteriorly, and bent upwards towards the dorsal aspect, entirely
ciliate ; the oral aperture anteriorly situated, pharynx enclosing a cylindrical
rod-fascicle. HAB. — Fresh water.

Phascolodon vorticella, Stein. PL. XLII. FIGS. 14 AND 15.

Width of the truncate anterior margin equal to or exceeding half the
length of the body, sharply pointed posteriorly ; the dorsal surface much
elevated and inflated ; cilia most conspicuously developed round the anterior
margin and the posterior half of the ventral surface ; endoplast central, oval,
containing a minute spheroidal endoplastule ; contractile vesicles two in
number, one stationed in front of and the other behind the endoplast.
Length of body 1-288". HAB. — Fresh water.

Viewed from the dorsal surface, this animalcule, with its convex back and
ciliated anterior margin towards the observer, presents the aspect of a free Vorticella,
and it is only when turning over and thus exhibiting its flat ventral surface and cha-
racteristic pharyngeal rod-fascicle, that its true nature becomes apparent. Stein
never observed this species creep over aquatic substances after the manner of
Chilodon and its other nearest allies, its habitual motion being that of uninterrupted
rotation through the water. This peculiarity, together with its characteristic form,
distinguishes this type essentially from the ordinary Hypotricha, and would seem, as
intimated by Stein, to indicate its true position as transitional between the last-
named order and that of the Peritricha. The younger forms of Phascolodon, with
the exception of being somewhat more attenuate, differ but little from the adults,
and are referred to by Stein as presenting some superficial resemblance to Ehren-
berg's Trichodina vorax*

GENUS II. CHILODON, Ehrenberg.

Animalcules persistent in shape, but more or less flexible, subovate,
produced anteriorly into a lamellar, lip-like prominence ; the dorsal region
convex, the ventral surface perfectly flat, entirely ciliate ; oral aperture
debouching upon the centre of the anterior body-half, succeeded by a tubular
pharynx, associated with a cylindrical rod-fascicle, the anterior or distal
edges of which are protrusible beyond the cuticular surface ; anal aperture
postero-terminal ; dividing by both transverse and longitudinal fission.
Inhabiting salt and fresh water.

Chilodon cucullulus, Mull. sp. PL. XLII. FIGS. 16-22.

Body very flexible, subovate, twice as long as broad, rounded poste-
riorly, the lip-like projection of the anterior extremity sharply pointed,
curved towards the left ; the ventral surface ciliate throughout, but the
cilia larger and more conspicuous on the front margin and left side of the
anterior extremity ; an undulating line or groove leading diagonally from
the apex of the lip-like prominence to the oral aperture ; endoplast ovate or

* A reference to this very doubtful species was inadvertently omitted in the account already
given of the genus Trichodina (pp. 645 to 649). So far as it is possible to judge from Ehrenberg's
figures and brief description the type would appear to represent either an elongate species of Strom-
bidium or the detached zooid of some attenuate sedentary Vorticellidan, such as EpittyUt digitalis
or E. anastatica.

GENUS CHILODON. 747

fusiform, median, with a distinct centrally enclosed endoplastule ; contractile
vesicles many in number, irregularly distributed. Length of body 1-250"
to 1-84". HAB. — Salt and fresh water.

This species represents one of the commonest infusorial forms, it abounding in
both fresh and salt water and in stagnant infusions. Since under different conditions
it presents a variety of aspects, it has, as might be anticipated, received at the
hands of independent observers a multiplicity of titles. Among the numerous
synonyms that Stein has thus found it necessary to divest this species of in his
admirable monograph of the Hypotricha, the following ma'y be mentioned : — Colpoda
cuculhilus and C. cuculio of O. F. Miiller, Loxodes cucullulus and Chilodon uncinatus
of Ehrenberg, Loxodes cuculhilus, L. cuculio, and Z. dentatus of Dujardin, and Chilodon
uncinatus, Loxodes cucullulus, L. cuculio and L, brevis, and Chilodon uncinatus of Max
Perty. All of these so-called species are now shown to be mere transitional growths
or imperfectly observed examples of one and the same type, and for which the
distinctive title of Chilodon cucullulus, as first applied to it by Ehrenberg, must
be retained. A large number of the synonyms above quoted would seem to have
arisen from the observation and description of the animalcule in its immature state,
and at which period, as shown by Stein, its aspect differs considerably from that
of the adult form. Thus while in its mature condition the animalcule, through
the greater induration of its dorsal cuticular surface, is tolerably rigid and constant
in form, this does not apply to the species when first released from the egg or
spore, or when liberated from their characteristic capsular encystments. Under
these conditions the entire body is completely soft and plastic, the anterior
extremity is more rounded, and the general appearance of the animalcule more
nearly approximates that of the Holotrichous genus Colpoda. Multiplication by
both transverse and longitudinal fission is common in this species, the last named
process, according to Stein, being likely to be mistaken for the phenomenon of con-
jugation. The characteristic oral or pharyngeal rod-fascicle makes its appearance at
a very early stage, before indeed the appearance of the cilia or its extrusion from
the sporocyst, and is likewise developed in duplicate as a preliminary to the
process of longitudinal or transverse fission. Examples of this species were
recently obtained by the author in vast quantities from a small road-side gutter near
St. Heliers, Jersey. Every individual almost was found to be gorged with small
Naviculce and other minute Diatomaceae, which constitute a favourite diet of this
animalcule. Examined with a power of about 700 linear, the disposition of the
ventral cilia in fine parallel lines was clearly shown, as also that the cilia upon these
lines work in an opposite direction on each side, finally converging at the oblique
anterior linear groove, and conducting the current of water down this channel to
the mouth. Stein represents this groove as a simple oblique line clothed with a
differentiated and more closely approximated fringe of cilia. In specimens killed by
the application of osmic acid it was clearly demonstrated, however, that this line is
not specially ciliated, but forms a narrow gutter-like channel for the conduct of
food-particles to the oral aperture. The elongate ovate endoplast with its enclosed
endoplastule was very distinctly exhibited in the majority of examples examined.

The author is indebted to Mr. Charles Stewart, of St. Thomas's Hospital, for
the opportunity of examining preserved examples of Chilodon cucullulus that are
distinguished by a highly interesting development of the elements entering into the
composition of the pharyngeal armature. In place of contributing towards the
formation of a symmetrical subcylindrical tubular fascicle, as usually obtains, the
inferior or proximal denticles more especially are developed backwards to a
remarkable extent and recurved upon themselves in the manner illustrated in
PL XLII. Fig. 20. The general effect produced is suggestive to some extent of the
not infrequent development of a rodent's incisor teeth, as brought about through
the loss or injury of the opposing set, and which under ordinary conditions restrain
their growth beyond the normal limit.

748 ORDER HYPOTRICHA.

GENUS III. LOXODES, Ehrenberg.

Animalcules free-swimming, elastic, but persistent in form, more or less
elongate and lamellate ; the dorsal surface slightly convex, perfectly smooth
and naked, with a marginal border of short, hispid setae ; the ventral surface
furrowed longitudinally, clothed throughout with fine, even cilia ; oral
aperture ventral, subterminal, approached by a channel-like ciliated groove,
continued posteriorly into a tubular pharynx ; the walls of the pharynx
and adoral groove strengthened by a continuous sigmoidal or sickle-shaped
indurated membrane ; contractile vesicles numerous (?) ; endoplast com-
pound, racemose.

Out of the numerous species formerly referred to the genus Loxodes by Ehrenberg,
Dujardin, and Perty, a single type only, L. rostrum, is now retained, the remainder
being referred in the majority of instances, by more modern investigators, to the
several genera Param<zcium, Aspidisca, Chilodon, and Amphileptus. Engelmann,*
who was the first to recognize the distinctive character of the dorsal and ventral
surface of the type form — the cuticle being described by Claparede and Lachmann
and all previous writers as evenly ciliate throughout — added to his detection of the
marginal border of setae, presumed he had an undescribed Infusorium under exami-
nation, and proposed for it the generic and specific title of Drepanostoma striata.
Its identity, however, with the Loxodes rostrum of Ehrenberg has since been
clearly demonstrated by Wrzesniowski,t and its entire structure most care-
fully worked out. As first intimated by Engelmann, the limitation of the cilia to
the lower surface, combined with the presence of the border of marginal setae, neces-
sitates the relegation of this type to the Hypotrichous section. Among these it
claims, with reference to the last-named structural characteristic, a relationship
with the setiferous Oxytricha, while with reference to the oral armature and character
of the ciliation, it more nearly approaches Chilodon. Through the genus Litonotus
of Wrzesniowski, Loxodes may be further said to retain its connection with the group
of the Holotricha with which, up to a recent date, it has been identified.

Loxodes rostrum, Ehr. PL. XLII. FIGS. 1-3.

Body very flexible, flattened, somewhat scimitar-shaped, about four and
a half times as long as broad ; the anterior extremity curved slightly to the
left and terminating in a beak-like point, the posterior extremity also
curving slightly inwards in the same direction, and angular on its left-hand
border ; the oral aperture debouching on the left side of the ventral surface
at a little distance from the apical extremity, a distinct adoral groove
produced from thence in an arcuate form to the apex of the anterior
beak-like point; the tubular pharyngeal cleft extending backwards in an
oppositely directed curve towards the right-hand border ; the walls of the
pharynx and inner surface of the adoral groove strengthened by a con-
tinuous brown-coloured, sickle-shaped, corneous induration, the posterior
or pharyngeal portion of which alone is tubular, this structure as a whole
extending to a distance of nearly one-third of the length of the entire
body from the apical extremity ; vibratile cilia distributed throughout _the
longitudinal furrows of the ventral surface, those bordering the anterior
and posterior extremities most conspicuous ; a fringe of somewhat larger
* 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xi., 1861. ,t Ibid., 1870.

GENUS OPISTHODON. 749

cilia bordering the adoral groove ; marginal setae very short and fine,
scarcely equalling the cilia in length ; parenchyma tawny yellow, highly
vacuolar ; contractile vesicles numerous, posteriorly situated (?) ; endo-
plasts numerous, spherical, usually with laterally attached endoplastules,
distributed throughout the length of the parenchyma, and connected with
each other by a cord-like filament or funiculus ; a row of spherical refringent
corpuscles usually developed in the vicinity of the right-hand margin of
the anterior region of the body ; animalcules swimming evenly or rotating
on their axis and creeping over foreign substances. Length 1-150'' to 1-50".
HAB. — Stagnant water.

The vacuolation of the substance of the parenchyma in this species closely
resembles that of Trachelius ovum or Noctiluca, and is sometimes developed to such
an extent as to leave beneath the cuticular surface a mere network of protoplasmic
trabeculae. As a rule, the vacuolation is most conspicuous towards the posterior ex-
tremity. The incepted food-particles transported from the oral region pass freely
into this protoplasmic network and are retained within its substance, in no case
intruding into the intervening vacuolar spaces. Claparede and Lachmann, in
accordance with the more highly organized multicellar structure claimed by them
for the Ciliate Infusoria, have conceded to this food-enclosing network the function
of a tubular, ramifying, membrane-bounded intestinal tract, allotting at the same time
to the intervening lacunae the role of a rudimentary abdominal cavity. The incon-
stant character of this vacuolar system, however, it presenting a diverse aspect in
different examples, and not being permanent in character in even the same animal-
cules, sufficiently demonstrates the untenability of this interpretation. The possession
by Loxodes rostrum of distinct contractile vesicles has not up to the present time been
definitely established. Claparede and Lachmann are, however, inclined to regard as
equivalent to such structures the rounder and more persistent vacuolae developed at
the posterior extremity of the body, and record the periodic inflation and contraction
of this entire region. As first pointed out by Johannes Muller, some structures of
a peculiar and as yet unexplained nature are found attached to the inner surface of
,the cortical parenchyma ; these are of spherical shape, clear and transparent, enclose
a central nucleolar-like body, and are distributed in an even line adjacent to and
parallel with the right marginal border. A possible secretive function has been rele-
gated to these bodies by Claparede and Lachmann and other authorities. The
racemose development of the numerous spherical endoplasts or nuclei, with their
attached endoplastules, is best illustrated, as demonstrated by Wrzesniowski, see
PI. L. Fig. 14, through the employment of a one per cent, solution of acetic acid.
In many instances, as pointed out by the last-named authority, the endoplastule,
instead of being affixed to the endoplast, is found attached separately to the
connecting cord or funiculus, while in other cases it may be entirely absent. The
specialized corneous armature of the pharynx and adoral groove, interpreted
correctly in the first place by Engelmann, was noticed and described by earlier
observers as a mere local aggregation of dark -brown pigment-granules. The peculiar
hue of this structure, dark chestnut brown in adult examples, and more transparent
in younger individuals, is at once suggestive of the similarly coloured corneous loricae
of various Vaginicolinae ; the chemical composition of the two is probably identical.

GENUS IV. OPISTHODON, Stein.

Animalcules free-swimming, ovate or egg-shaped, the dorsal surface
more or less convex, the ventral surface plane, entirely ciliate ; oral aperture
situated towards the posterior half of the body, supplemented by a cylin-
drical pharyngeal rod-fascicle. Inhabiting fresh water.

750 ORDER HYPOTRICHA.

Opisthodon niemeccensis, Stein. PL. XLII. FIG. 23.

Body elongate-ovate, rounded and widest posteriorly, attenuated and
pointed at the anterior extremity, its apex curved slightly towards the
right; the centre of the body circumscribed by an inner line or band
parallel with that of the outer margin; the dorsal surface moderately
convex, the ventral one flat and even ; cilia most conspicuously developed
towards the anterior region ; the oral aperture opening at a distance of
about one-quarter the length of the entire body from the rounded posterior
end ; endoplasts two in number, spherical, located centrally towards the
left side ; contractile vesicles numerous, a larger one usually situated
on the right side, immediately opposite 4he two endoplasts. Length of
body i-i 50". HAB. — Fresh water.

GENUS V. CHLAMYDODON, Ehrenberg.

Animalcules free-swimming, persistent in form, ovate or kidney-shaped,
the dorsal surface convex, the ventral one plane, bounded by a raised border,
its central area alone entirely ciliate ; oral aperture situated in the anterior
half of the body, supplemented by a pharyngeal rod-fascicle.

Chlamydodon Mnemosyne, Ehr. PL. XLII. FIGS. 41 AND 42.

Body short, kidney-shaped, the two extremities equally rounded, the
anterior end somewhat the wider, both curved slightly towards the left ; the
dorsal surface convex, its lateral margin evenly elevated ; the ventral sur-
face bounded by a raised, transversely striate border ; cilia most conspicuous
at the anterior extremity, whence they project as a fringe beyond the
margin of the body ; mouth debouching upon the centre of the anterior body-
half ; endoplast single, ovate, subcentral ; contractile vesicles numerous,
minute ; dividing by transverse fission. Length of body 1-300".

HAB. — Salt water.

GENUS VI. SCAPHIDIODON, Stein.

Animalcules free-swimming, scaphoid or boat-shaped, convex above,
flattened below ; the posterior extremity produced in a beak- or spur-like
form, the anterior edge having a lip-like border; the centre field of the
ventral surface thickly ciliate ; oral aperture anteriorly situated, supple-
mented with a pharyngeal rod-fascicle. HAB. — Salt water.

Scaphidiodon navicula, Miiller sp. PL. XLII. FIGS. 49 AND 50.

Body boat-shaped, the breadth equal to about one-third of the total
length ; the anterior margin truncate, the posterior region attenuate, con-
tinued in a spur-like form, with its extremity curved towards the left;
the ciliary system of the ventral surface produced in a fringe-like manner
beyond the truncate anterior margin ; endoplast central, oval ; contractile

GENUS SCAPHIDIODON. 751

vesicles two in number, occupying an antero-posterior position on the right
side of the body. Length of body, including spur, 1-240".
HAB. — Sea water.

The type of this species and genus as instituted by Stein is the Trichoda navicula
of Miiller. The likeness that subsists between this animalcule and the immature
condition of Litonotus fasciola is referred to in the account given of that species.

Fam. III. DYSTERIIDJE, S. K.

Animalcules free-swimming, more or less ovate, cylindrical, flattened,
or compressed, mostly encuirassed, the carapace simple or consisting of
two lateral, subequal, conjoined or detached valves ; cilia confined to the
more or less narrow and constricted ventral surface; the oral aperture
followed by a distinct pharynx, the walls of which are strengthened by a
simple horny tube, by a cylindrical fascicle of corneous rods, or by other-
wise differentiated corneous elements ; a conspicuous, tail-like style or
compact fascicle of setose cilia, presenting a style-like aspect, projecting
from the posterior extremity. Mostly inhabiting salt water.

The representatives of this family were included in Stein's monograph of
the Hypotricha,* as a sub-family only of the Chlamydodonta, with which they
present many points in common, but are elevated in his succeeding volume,f to
the rank of an independent family group for which he retains Dujardin's previously
conferred title of the Ervilina, as instituted by the last-named authority for the
reception only of the two genera Ervilia and Trochilia. As shown, however,
later on — see genus sEgyria — the name of Ervilia, adopted by Dujardin, had
been previously occupied by Turton to denote a genus of Mollusca, and has con-
sequently, in common with the family title derived from it, to be expunged from
the nomenclature of the Infusoria. While closely allied to the Chlamydodontidse,
with which they are most directly united perhaps through the genus Trochilia, all
the members of the Dysteriidag may be distinguished by the presence of the
peculiar caudal appendage developed at the posterior extremity, and which, with
one exception only, takes the form of a pointed spine or style. This caudal spine or
style, while rigid in itself, is movable upon its point of attachment as though on a
hinge-joint, or rather a cup-and-ball socket, and is utilized by the animalcules for
the same purpose as the so-called "foot" or caudal style of the free Rotifera.
The aspect of its possessor, indeed, when attached by this point cCappui to any
convenient fulcrum of support, fishing for its food with its oral cilia, and turning
or bending upon its terminal style as though on a pivot, is so strongly suggestive of
certain members of the above-named higher class of organisms, that it is scarcely to
be wondered that in certain instances, as, for example, in the case of JDysteria armata,
the rotiferal or infusorial affinities of the organisms should have been a matter of
dispute. Certain representatives of the Dysteriidae, again, manifest a mimetic
resemblance to an entirely distinct organic group. Reference is here made to those
genera distinguished by their possession of a bivalved carapace, often variously
grooved and sculptured, and which, together with their long projecting ventral cilia,
imparts to them, as alluded to in the account of the genus Cypridium, a remarkable
superficial likeness to minute Ostracodous Crustacea. No such compound modi-
fication of the carapace is as yet known to exist in any of the remaining groups
or orders of the Infusoria. The number of specific types referable to the Dysteriidae

: Organismus,' vol. i., 1859. f Ibid., vol. ii., 1867.

752 ORDER HYPOTRICHA.

has been greatly augmented by the researches of Messrs. Claparede and Lachmann >
recorded in their well-known 'Etudes sur les Infusoires,' published in the years
1858-60.

GENUS I. IDUNA, C. & L.

Animalcules free-swimming, encuirassed, oblong, bilaterally compressed ;
carapace formed of two distinct, entirely separate plates or valves, one
being developed on each side of the body ; a tail-like style or spine pro-
jecting from the posterior extremity of the narrow and finely ciliated ventral
groove ; the oral aperture opening on the antero-ventral border ; pharyngeal
armature consisting of a single subcylindrical horny tube.

Iduna sulcata, C. & L. PL. XLII. FIGS. 24-26.

Right valve of the carapace convex, raised into four longitudinal, elevated,
angular costae ; the left valve plane, perfectly smooth, not descending so
low on the ventral border as the opposite one ; tail-like style short and
conical ; contractile vesicles two in number ; pharyngeal tube bent. Length
of body 1-175". HAB. — Salt water : Norwegian coast (C. & L.).

GENUS II. DYSTERIA, Huxley.

Animalcules free-swimming, ovoid, encuirassed, bilaterally compressed ;
the ventral surface entirely ciliate, narrow, and groove-like ; carapace com-
posed of two lateral pieces, united to each at the posterior end only of the
dorsal margin ; pharyngeal armature complex, consisting of an annular,
compound, anterior, horny portion, and a long, posteriorly produced stylate
process ; a tail-like spine projecting from the posterior region of the ventral
groove.

Dysteria armata, Hux. PL. XLII. FIGS. 27-30.

Valves of carapace oval, the right one more convex, its surface smooth ;
the left valve traversed near its dorsal margin by a longitudinal angular
ridge, not extending so far forward as the right one ; ventral style lanceo-
late, situated at a distance of one-fifth of the length of the body from the
posterior extremity, its proximal portion hollow; stylate process of the
pharynx produced upwards and backwards through the centre of the body
to the point opposite the origin of the ventral style ; the contractile vesicle
single, subcentral ; an amethyst-coloured globule or pigment-spot invariably
developed immediately above the anterior or annular portion of the pharynx.
Length of body 1-350" to 1-250". HAB.— Salt water.

Immediately succeeding the description of this animalcule by Professor Huxley *
some discussion arose concerning the question of its true affinities. While its
discoverer pointed out, what is now a generally -acknowledged fact, that it exhibited
a close structural correspondence with the Euplotes (^Egyria) monostyla, misquoted
" macrostyla" and the Chlamydodon mnemosyne of Ehrenberg, Mr. P. H. Gosse,
dissenting from this interpretation, advocated the opinion f that the structure

* ' Journal of Microscopical Science,' 1857, p. 78, f Ibid., p. 138.

GENUS D YSTERIA. 753

of Dysteria was altogether too complex for an infusorial animalcule, and that its
correct position was more probably among the more highly organized Rotifera some-
where near the genera Monocerca and Mastigocerca. Mr. Gosse at the same time sug-
gested that this type might be regarded as an annectant form between the Rotiferae
and the Ciliate Infusoria. Among the large number of undoubted Infusoria now known
to possess an essentially equivalent type of structure, and here included under the
family title of the Dysteriidae, those assembled under the new generic title of Cypridium
most closely resemble the present type. These in a like manner possess a somewhat
unsymmetrical bivalvular carapace, the dorsal borders of which are posteriorly
united to one another, and are also provided with a similar posteriorly attached
caudal style. The only substantial point of distinction between the two is found
in the character of the pharyngeal armature, which in Dysteria is far more complex
than in other members of the same family group.

The more minute details of the indurated pharyngeal apparatus of Dysteria,
as described by Professor Huxley, may be suitably reproduced. The oral fossa
is, in the first instance, strengthened by a curious curved rod, which terminates
superiorly in a bifid tooth, while inferiorly it appears to become lost in the walls
of the fossa. This is followed by the pharyngeal apparatus proper, which may
be said to consist of two portions — an anterior, somewhat rounded mass, in appo-
sition with a much elongated, styliform posterior portion. As intimated by Prof.
Huxley, it is very difficult to assure oneself of the precise structure of the complex
anterior portion. It appears, however, to form a deep ring composed of three
pieces — two supero-lateral and mutually corresponding, united with a third, inferior,
azygos portion. The element last named is somewhat triangular, with a broad
base and rounded obtuse apex. This apex is directed forwards and immediately
underlies the oral aperture, while the base is turned backwards and unites with
the two supero-lateral pieces. Each of these latter is concave internally, and convex
externally, so as to form a segment of a circle, and presents a clear median space,
the optical expression either of a perforation or of a much-thinned spot. The
anterior edge of each supero-lateral piece is nearly straight, but the posterior border is
convex, and articulates with, or is apposed to, the anterior extremity of the posterior
or styliform division of the apparatus. Viewed laterally, this posterior portion
appears to consist of two styles which are somewhat like nails in shape, their
anterior extremities being truncated so as to somewhat resemble a nail-head,
while the posterior extremity seems to taper to a fine point. Rather in front of the
middle of its inferior edge each style apparently gives off a short process downwards,
which process is, in botanical language, decurrent upon the style. Careful examina-
tion of the dorsal or ventral aspect of these parts shows that the decurrent process is
in fact only the optical expression of a delicate membrane, which is bent so as to
have a ventral convexity, and connects together the two styles. It might be said,
therefore, that the posterior part of the apparatus is a triangular membrane, deeply
excavated in front, bent so as to be convex downwards, and having its margins
thickened and produced into styliform enlargements. This curious piece of
mechanism is directed upwards and backwards, and terminates in the substance of
the body without any apparent connection with other parts.

From the foregoing description of the pharyngeal armature of Dysteria as recorded
by Professor Huxley, it is evident that the elongate and backward produced so-called
styliform appendage or posterior portion only of this apparatus coincides with the
more ordinary pharyngeal armature of Iduna, <dEgyria, and other representatives of
the same and preceding family groups, the components of the complex annular
anterior portion being entirely accessory. It may be further remarked that this
coincident pharyngeal portion, as above described, exhibits a type of structure midway
between that of the simply tubular corneous induration of Iduna and the cylindrical
rod-fascicle of such types as Chlamydodon and Chilodon, The animalcules which fur-
nished the material for Professor Huxley's description were remitted him by
Mr. Dyster, in whose honour the genus was named, and were found in swarms
among confervoid algae that coated the shells of a Patella and a Littorina which had

VOL. II. U

754- ORDER HYPOTRICHA.

long inhabited a small marine aquarium. A reproduction of the illustrations accom-
panying the original description of this relatively complex type will be found at
PI. XLIL Figs. 27-30.

GENUS III. CYPRIDIUM, S.'K.

(Cypris ; oidos, like.)

Animalcules free-swimming, encuirassed, elongate ovate or oblong,
bilaterally compressed ; the ventral surface ciliated, narrow and groove-like ;
the right and left valves of the carapace coalescing with one another at the
posterior end only of the dorsal border ; a tail-like spine or style projecting
from the posterior extremity of the ventral groove; pharyngeal armature
consisting of a simple, cylindrical horny tube. Mostly inhabiting salt
water.

The author has conferred this new generic title upon various species referred by
Claparede and Lachmann* to the genus Dysteria, from which, however, they are to be
distinguished by the simple tubular character of the pharyngeal armature. The
superficial resemblance of these bivalved Infusoria to certain Ostracodous Crustacea,
such as Cypris, has suggested the generic name adopted.

Cypridium lanceolatum, C. & L. sp. PL. XLIL FIGS. 31-33.
Valves of carapace ovate, much narrower posteriorly, the left one having
a raised, arcuate, longitudinal costa, extending the whole length of and
adjacent to the dorsal region, emarginate at its anterior border ; the right
valve perfectly smooth and rounded ; pharyngeal tube slender, straight,
developed backwards to the centre of the body ; the posterior or caudal style
lanceolate, equal in length to nearly one-half the diameter of the carapace ;
the cilia longer and more thickly developed at the anterior extremity ;
contractile vesicles two in number, situated near the ventral surface ;
endoplast single, spherical, subcentral. Length of body, 1-350".
HAB. — Salt water : Norwegian coast (C. & L.).

This species is identical with the Dysteria lanceolata of Claparede and
Lachmann.

Cypridium spinigerum, C. & L. sp. PL. XLIL FIG. 34.
Valves of carapace elliptical, the more convex valve having a single
longitudinal sulcus and two spinous prominences on the dorsal border ; the
opposite one plane, smooth, and entire ; caudal style long and slender.
Length of body 1-400". HAB. — Saltwater.

A very imperfect description of this genus is given by Claparede under the title
of Dysteria spinigera, and in which it is left undetermined whether it is the right or
left valve that is sulcated and bears the spinous processes, while no details are
recorded concerning the pharyngeal tube, nor as to the dimensions of the animalcule.
It is stated, however, to be smaller than the species last described, C. lanceolatum.

Cypridium aculeatum, C. & L. sp.

Valves of carapace elliptical, subequal ; the right valve the more convex,
having a marginal dorsal crest which terminates anteriorly and posteriorly

* ' Etudes sur les Infusoires,' 1858-60.

GENUS &G YRIA . 755

in a minute spine ; the left valve with a less developed crest and a posterior
spine only; pharyngeal tube simple, slightly curved. Length of body
1-250". HAB. — Saltwater: Norwegian coast.

This species corresponds with the Dysteria aculeata of Claparede and
Lachmann.

Cypridium crassipes, C. & L. sp.

Valves of carapace elliptical, widest posteriorly, united throughout the
posterior half of their dorsal surfaces ; both equally and entirely smooth ;
the caudal style very thick, its proximal extremity hollow, its distal one
sharply pointed ; pharyngeal tube simple, short, and straight ; contractile
vesicles two in number; endoplast spherical, subcentral. Dimensions
unrecorded. HAB. — Salt water.

Identical with the Dysteria crassipes of Claparede and Lachmann.

GENUS IV. ^GYRIA, C. & L.

Animalcules free-swimming, encuirassed, oblong, more or less bilaterally
compressed, valves of carapace two in number, united throughout the
dorsal border. A movable tail-like style projecting from the posterior ex-
tremity of the ventral groove. Pharyngeal armature consisting of a simple
horny tube. Inhabiting salt and fresh water.

The more extensive coalescence of the valves of the carapace upon their
dorsal border serves to distinguish this genus from the preceding one. Many of its
members have been described, in the first place by Dujardin and subsequently
by Stein, under the generic name of Ervilia ; but as this title has been previously
employed by Turton in the year 1822 for a genus of the Mollusca, and also by Link
for a genus of leguminous plants, the one of sEgyria, proposed as a substitute by
Claparede and Lachmann, is here retained.

.flQgyria monostyla, Ehr. sp. PL. XLII. FIGS. 35 AND 36.

Valves of carapace elongate-rectangular, rather wider posteriorly, with
rounded corners, about twice as long as broad, the left valve having a
raised longitudinal border along the dorsal margin ; endoplast ovate, sub-
central ; contractile vesicles two or three in number. Length of body
1-300". HAB — Salt water.

This species is described by Stein under the name of Ervilia monostyla, it being
regarded by him as identical with the Euplotes monostyla of Ehrenberg and the
Ervilia legumen of Dujardin. In Claparede and Lachmann's work it takes its
place under the generic title here retained, as ^Egyria legumen ; since, however, its
identity with Ehrenberg's type is considered proved, the specific title first conferred
upon it by that earlier authority must necessarily take the precedence.

.ffigyria angustata, C. & L. PL. XXII. FIGS. 39 AND 40.

Valves of carapace irregularly ovate, the left valve convex, the right
one plane, abruptly narrowed and obliquely truncate anteriorly, the width
immediately following this narrower anterior portion nearly equal to the

U 2

756 ORDER HYPOTRICHA.

total length and so continuing to the posterior extremity; the surface of
both valves smooth and entire ; caudal style short and sharply pointed ;
pharyngeal tube long and slender, extending nearly to the centre of the
body; contractile vesicles two in number. Length of body 1-300".
HAB.— Salt water.

.ZEgyria oliva, C. & L. PL. XLII. FIGS. 43 AND 44.

Valves of carapace ovate, but slightly compressed, smooth and entire
throughout ; the ventral groove wide ; caudal style short, conical, situated
at some little distance from the posterior extremity, and not projecting
beyond its border ; a dark eye-like pigment-spot developed towards the
anterior end ; pharyngeal tube short and straight. Length of body 1-250".

HAB. — Salt water : Norwegian coast.

The less compressed contour of this form, compared with that of the preceding
species, approximates it towards the genera Phascolodon and Chlamydodon of Stein,
from which, however, it differs in its possession of a caudal style and in the
character of pharyngeal tube. The dark eye-like pigment-spot at the anterior extremity,
observed by its discoverers, is apparently homologous with the so-called amethystine
spot or globule in Professor Huxley's Dysteria armata, and with the eye-like pigment-
spot of Ophryoglena and many Flagellata.

.ffigyria pusilla, C. & L.

Valves of carapace ovate, small, narrowed anteriorly, their surface
smooth and even ; ventral groove somewhat widened ; caudal style conical,
projecting posteriorly. Length 1-600". HAB. — Salt water.

This form is briefly described by Claparede and Lachmann as being of much
smaller size than any other members of the genus they examined, its dimensions not
allowing them to ascertain the character of the pharyngeal tube. An animalcule
closely resembling this one in size and aspect was observed by the same writers in
fresh water from the river Spree, and is regarded by Stein as probably identical with
his Ervilia (sEgyria) fluviatilis, next described.

.ffigyria fluviatilis, Stein sp.

Valves of carapace ovate, compressed obliquely, truncate anteriorly ;
the right valve convex, ornamented by five longitudinally raised costae, the
left valve smooth and plane ; pharyngeal tube simple throughout, extending
backwards to the centre of the body ; endoplast ovate, subcentral. Length
of body 1-750". HAB. — Fresh water.

Stein observed examples of this species, which is described by him under the
title of Ervilia fluviatilis, undergoing the process of transverse fission. The speci-
mens examined were discovered in the clear water of a mountain stream in the
neighbourhood of Tharaunch.

GENUS V. TROCHILIA, Dujardin.

Animalcules free-swimming, ovate, encuirassed, with a convex dorsal
and plane ventral surface, the anterior extremity usually curved towards

GENUS HUXLEY A. 757

the left ; a movable stylate appendage attached to the posterior extremity ;
cilia confined to a subcentral, curved, band-like area of the ventral surface ;
oral aperture opening on the anterior half of the body, supplemented by a
simple horny tubular pharynx, a single long, stiff cilium or seta projecting
externally from the oral fossa. HAB. — Salt and fresh water.

Trochilia palustris, Stein. PL. XLII. FIGS. 51 AND 52.

Body ovate, gibbous, its breadth equal to about two-thirds of its total
length, the anterior extremity obliquely truncate, curved towards the left,
the stylate caudal appendage equal to one-third of the length of the
body, directed towards the left side ; the central ciliated band following the
curvature of the right side of the body, slightly widest at the anterior end,
and gradually tapering towards the posterior extremity ; endoplast oval,
situated towards the centre of the left side ; contractile vesicle single,
spherical, occupying a similar position on the right-hand border. Length
of body 1-750". HAB. — Freshwater.

A species having only about half the dimensions of T. palustris, but otherwise
resembling it, has been described by Wrzesniowski under the title of T. polonica.

Trochilia sigmoides, Duj. PL. XLII. FIGS. 47 AND 48.

Body ovate, the posterior extremity rounded, the anterior one pointed,
curved towards the left ; the dorsal surface of the carapace ornamented with
five or six conspicuous longitudinal, somewhat oblique ribs or flutings.
Length of body i-i 150". HAB. — Salt water.

The Huxleya sulcata of Claparede and Lachmanni s identified by Stein with
this form, and a comparison of the original figure and description of the type given
by Dujardin with that of the more recent Swiss authorities, here reproduced, would
seem to justify the endorsement of Stein's conclusions.

Trochilia marina, Meresch.

Body oval, slightly compressed ; dorsal surface ornamented with two
grooves which extend throughout the entire length of the body. Length
1-750". HAB. — Salt water : Black Sea (Mereschkowsky).

GENUS VI. HUXLEYA, C. & L.

Animalcules free-swimming, persistent in form, but not encuirassed,
more or less ovate or subcylindrical, having a narrow entirely ciliate ventral
furrow, and a posteriorly developed caudal style ; no anteriorly projecting
oral seta.

As first pointed out by Stein, the Huxleya sulcata of Claparede and Lachmann is
synonymous with the Trochilia sigmoides of Dujardin. The Huxleya crassa of the
same authorities is, however, an animalcule exhibiting structural differences
sufficient to permit of its being retained as the type of a distinct genus, and
simultaneously of rescuing from extinction a world-honoured title that must otherwise

758 ORDER HYPOTRICHA.

have been banished from zoological taxonomy. The genus Huxleya, as typified by
H. crassa, differs from Trochilia in its naked, non-encuirassed cuticular surface,
in its almost perfectly cylindrical instead of flattened contour, and in the absence
of the long cilium or seta that projects from the oral region. Unfortunately,
Claparede and Lachmann failed to ascertain whether the pharynx was armed after
the manner of the ordinary Dysteriidse, though no doubt this structural element
will be found, on further investigation, to exhibit characters of important diagnostic
value.

Huxleya crassa, C. & L. PL. XLII. FIGS. 37 AND 38.

Body oval, subcylindrical, equally rounded at the two extremities,
about one and a half times as long as broad ; a raised circular border
developed at a short distance from the posterior extremity, such border
imparting to the animalcule, in conjunction with the rounded caudal region
and appended style, an acorn-like aspect. Length of body 1-350".

HAB. — Salt water : Norwegian coast (C. & L.).

GENUS VII. TRICHOPUS, C. & L.

Animalcules free-swimming, not encuirassed, compressed, the narrow
band-like ventral surface entirely ciliate, terminating posteriorly in a
compact fascicle of setose cilia, which takes the place of the caudal style
in the preceding Dysteriidae ; oral aperture followed by a cylindrical
pharyngeal rod-fascicle ; endoplast single, ovate ; contractile vesicle single,
spherical, situated near the posterior extremity.

Trichopus dysteria, C. & L. PL. XLII. FIG. 46.

Body subpyriform, about twice as long as wide, largest and inflated
posteriorly, abruptly narrowed towards the anterior extremity ; the dorsal
and lateral surfaces entirely smooth ; the posterior ciliary fascicle short and
pointed, having a styloid aspect. Length of body 1-200".

HAB. — Salt water : Norwegian coast.

Though no reference to such a structure is made in the text, Claparede and
Lachmann represent, in their illustration of this species, a single long recurved cilium
as projecting from the anterior extremity, and which, if it actually exists, probably
corresponds with the somewhat similar projecting oral cilium or seta developed
in the genus Trochilia. The posterior fascicle of cilia in this type — apparently homo-
logous with the single stylate appendage occupying the same position in the ordinary
Ervilinae — is of especial interest, its origin and significance being comparable with
the analogous structure subsisting in the Peritrichous Urocentrum, with reference to
the genus Gyrocorys.

Fam. IV. PERITROMID^J, Stein.

Animalcules free-swimming, ovate or reniform, with a plane ventral and
convex dorsal surface ; the oral aperture ventral, debouching upon the
posterior angle of an excavated peristome-field, the outer or left-hand border
of which bears an arcuate fringe of large powerful adoral cilia or cirri ;

GENUS PERITROMUS. 759

the remaining portion of the ventral surface dotted with fine vibratile cilia
only, never developing supplementary setae, styles, or uncini.

The as yet single known representative of this family combines the
characters of the two groups of the Chlamydodontidae and Oxytrichidae, it uniting
the simply ciliate ventral surface of the former — as typified by the genus Chilodon —
with the edentulate pharynx, excavate peristome-field, and arcuate fringe of adoral
cilia characteristic of the latter. Its passage to the ordinary Oxytrichidae is
clearly through the genus Kerona, with which, except for the presence of vibratile
cilia in place of fine setae on the ventral surface, it would appear to closely corre-
spond. The isolation of Peritromus as the type of an independent family group,
upon which he confers the title of the Peritromina, is accomplished by Stein in the
second volume of his ' Organismus.'

GENUS I. PERITROMUS, Stein.

Animalcules free-swimming, reniform, depressed ; peristome-field ex-
tended backwards to the centre of the ventral surface ; no ventral or
anal styles or setae ; the whole under surface dotted with short fine cilia
which are distributed in closely approximated longitudinal lines ; endoplast
double ; contractile vesicle situated near the posterior edge of the peri-
stome ; anal aperture sub-terminal.

Peritromus Emmse, Stein.

-

Body reniform, widest posteriorly, about twice as long as broad, both
extremities equally rounded; the right lateral margin convex, the left one
indented* centrally ; peristome-field bow-shaped or arcuate, extending back-
wards to the median line, its outer edge bordered with long powerful
adoral cirri ; fine, short, vibratile cilia distributed in many parallel lines
over the remaining ventral surface. Dimensions unrecorded.

HAB. — Salt water.

In general contour, and in the form and character of the peristome, this species
closely resembles Kerona polyporum ; added to which, however, is the uniform
ciliary clothing of the under surface characteristic of Chilodon cucullulus. No illus-
tration of this interesting form, which has so far been observed by Stein only,
has as yet been published.

Fam. V. OXYTRICHIDAE, Ehr.

Animalcules free-swimming, ovate or elongate ; usually with a flattened
or concave ventral and a more or less convex dorsal surface ; peristome-
field ventral, triangular or arcuate ; oral ciliary system consisting of an outer
or right-hand marginal fringe of powerful adoral cirri, which is frequently
supplemented by an oppositely reflected or left-hand marginal series of
smaller pre-oral cilia, and more rarely by a median series of lax and
attenuate endoral cilia ; locomotive cilia setose, stylate, or uncinate,
variously distributed upon the remaining ventral surface and forming
separate sets or groups, distinguishable as the frontal, ventral, anal,
marginal, and caudal series ; supplementary, immotile, hispid, or hair-like

760

ORDER HYPOTRICHA.

setae occasionally developed upon the lateral margin, and more rarely on
the dorsal aspect ; oral aperture debouching upon the posterior angle of the
peristome-field, followed by a short tubular unarmed pharynx ; the anal
aperture ventral, located at a little distance from the posterior extremity ;
contractile vesicle single, endoplasts usually two or four in number.
Inhabiting salt and fresh water ; movements ambulatory or natatory.

With the Oxytrichidse we arrive not only at the most highly specialized group of
the Hypotricha, but, in many respects, at that also of the entire class of the Infusoria-
Ciliata. Structural differentiation is manifested more particularly in this family in
the remarkable development and relegation to varied purposes of the appendicular
or locomotive organs, and which, while in all instances more or less complex modifi-
cations of ordinary cilia, exhibit mostly a wide departure from the structures bearing
that title as met with in the orders previously described. By many earlier writers,
indeed — as explained more at length in the introductory chapter, see pp. 64 and 65 —
these appendages were regarded as distinct organs, and have been distinguished by
the respective titles of setae, styles, and uncini, &c. ; these terms are, however, in this
treatise retained only in an adjective or qualitative sense. Although at first sight

FIG. i.

FIG. 2.

-en

FIG. i. — Diagrammatic outline of Stylonychia mytilus, illustrating the several ciliary systems ;/, peristomal ciliary
series ; fr, frontal, v, ventral, an, anal styles ; m, marginal, and c c, caudal setae.

FIG. 2. — Peristomal ciliary system of Gastrosty'a Steinii (after Sterki) ; ad, adoral, pr&, praeoral, par, paroral, and
en, endoral series ; fr and m, isolated elements of the frontal and marginal systems.

there appears to be but little uniformity in the character and distribution of the
cilia upon the under surface of the more highly differentiated members of this
family, it will be found on closer examination that a certain common plan under-
lies and is predominant throughout. What this plan is, is best understood by a
brief study of the formula of arrangement exhibited in such a type as Stylonychia
mytilus, diagrammatically represented in Fig. i of the annexed woodcut, and which
is found to include all the elements, suppressed in some instances and exaggerated
in others, that occur in any of the numerous genera belonging to the group of the

FAMILl OXYTRICHIDAE. 761

Oxytrichidae. Apart from the peristome and its special series, presently referred to, the
modified cilia of the ventral surface may in this form be resolved into as many as five
distinct systems or groups. The first of these (fr) occupying the anterior and right-
hand region of the ventral aspect, or the one closely corresponding with that relegated
on the left side to the peristome-field, is distinguished by the title of the " frontal "
series. The normal number of the variously modified frontal cilia in Stylonychia and
certain other allied genera is seven or eight, out of which the more anterior three or four
are of unusually large proportions and claw-like or uncinate in shape, the remaining
smaller ones being stylate or setose ; all of these elements are more or less elastic,
capable of flexure in various directions, and fulfil the role of anterior ambulatory
appendages. The several genera, Psilotricha, Kerona, Stichotricha, and Stichochata,
furnish examples in which the frontal styles are entirely undeveloped or suppressed,
while in Stylonethes and certain species of Urostyla the more normal number of
eight is considerably exceeded.

The second and, for the purposes of generic discrimination, most important
group is that known by the name of the " ventral " series, and which, as its name
implies, occupies the most central area of the ventral aspect. In Stylonychia, as
indicated at v in the accompanying woodcut, and in some other genera, this ventral
group consists of five setose, stylate, or uncinate cilia only, whose disposition is
more or less quincuncial. These five primary ventral cilia are, in a few genera,
supplemented by one or more rows of usually smaller ventral setae, or, as occurs in
considerably the larger number of genera, is entirely replaced by a greater or less
number of such rows. In no member of the Oxytrichidae, as at present known, are
the ventral styles or setae entirely unrepresented, and the value of the characters
afforded by these elements, as an index to the leading generic subdivisions, becomes
apparent on reference to the schedule of the families and genera of the Hypotrichous
Order given on a preceding page.

The anal ciliary series (an), forming the third group, is stationed towards the pos-
terior extremity of the body and in close contiguity to the anal aperture. These cilia
are mostly of a stylate form, and often of more considerable size than those of the co-
associated groups. In the majority of instances, as exemplified in Stylonychia, they
are five in number and of a more or less rigid consistence, though not unfrequently,
as in Pleurotricha, they are flexible and participate with the ventral and frontal series
in the office of perambulation. In four genera only, among the Oxytrichidae, viz.
Stichotricha, Strongylidium, Uroleptus, and Stylonethes, is the anal series entirely
unrepresented. The fourth or " marginal" ciliary series (m) is composed usually of
short setose cilia, which form a more or less even fringe down each lateral border ;
these mostly meet together or are uninterrupted posteriorly, and present but
a slight amount of variation. In no member of the family is the marginal series
entirely absent, though in certain types, such as Amphisia, its normal character of a
bilateral peripheral fringe is departed from, the two lateral rows being removed far
inwards, close to the two central rows of ventral setae, with which in both size and
aspect they closely correspond. The fifth and but rarely represented group is the
caudal series (c), consisting of from two to four long hair-like setose cilia, which
project in a tail-like manner from the posterior border. In those animalcules in
which caudal setae occur, such as Stylonychia, it is worthy of note that the marginal
series is posteriorly interrupted, and that the former may therefore be interpreted as
representing abnormally developed elements only of the marginal set and not as a
wholly independent group. In addition to the from four to five ventral groups of
cilia just enumerated, it has been recently shown by Engelmann* that, in Stylonychia
mytilus and many other species, a supplemental peripheral fringe of fine immotile
hispid cilia is developed externally to the marginal series, these in certain cases —
e. g. Plagiotricha (Gonostomum) affinis and Oxytricha pelionella — being produced
likewise in even longitudinal rows over the entire dorsal aspect.

The peristomal or oral ciliary system of the Oxytrichidae is somewhat complex

'Zeitschrift fur Wissenschaftliche Zoologic,' Bd. xi., 1861.

762 ORDER HYPOTRICHA.

As already indicated in the diagnosis of the family characteristics, the peristome
field or oral region is of a more or less triangular or arcuate form, and may be
associated with no less than three or even four distinct ciliary series. The most con-
spicuous and essential of these series, being indeed never absent, is that bordering the
outer or left-hand margin, distinguished by the title of the " adoral " fringe. The
constituent cilia of this series are long and powerful, of a cirrate aspect, and admirably
adapted for the production, while the animalcule is stationary, of a constant food-laden
stream towards the oral aperture, while in the natatory condition they constitute the
chief organs of propulsion. According to Sterki,* each individual cilium of this series
is much compressed or lamellate, broad at its base, and gradually tapering towards
its distal extremity. A similar contour prevails also in the adoral cilia of Stentor and
other Heterotricha, and likewise in those of Halteria. As mentioned on a previous
page,f it has been proposed by the authority last mentioned to distinguish such
lamellate cilia by the name of " membranellse." The second series of cilia, mostly
but not invariably associated with the peristome-field, is that fringing its reflected
right-hand or inner border, and which is not unfrequently, as in Stylonychia mytilus
and Onychodromus grandis, supplemented with or even entirely replaced by a
band-like undulating membrane. This second fringe of cilia has received from
Sterki the title of the " pre-oral " series. The third series, of still less common
occurrence, while indicated by Stein in Pleurotricha and certain species of Oxytricha
and Urostyla, but described by him as an elongate groove, conducting to the oral
aperture, also owes its correct interpretation to the investigations of Sterki. It
occupies a position midway between that of the adoral and pre-oral fringes, and
consists of a linear series of exceedingly attenuate vibratile cilia, which taken
separately present a close resemblance to, flagella. This central series, which
descends posteriorly through the oral aperture into the tubular oesophagus, is
denominated by Sterki the " endoral " system. A fourth, but as yet rarely ob-
served series has been reported by the same authority as obtaining in Gastrostyla,
and this he proposes to distinguish as the " paroral " one. It occurs as an even
fringe of fine cirrose cilia, corresponding with those of the pre-oral system, but of
still smaller size, produced down the whole inner margin of the band-like border,
from the right side of which the powerful adoral cirri or cilia project. The
relationship of all the several ciliary systems here enumerated is clearly indicated in
Fig. 2 of the accompanying woodcut illustrating the peristomal region of Gastrostyla
Steinii, as interpreted by Sterki. A diagrammatic outline of the same region as
developed in Stylonychia mytilus, will be found at PI. XLV. Fig. i.

GENUS I. PSILOTRICHA, Stein.

Animalcules encuirassed, flattened, more or less oblong; having two
rows of long median ventral setae, and a border of similar setae developed
around the periphery, but possessing no frontal or anal styles ; endoplast
double. Inhabiting fresh water.

The indurated carapace and absence of the frontal styles serve to distinguish
this genus from Uroleptus.

Psilotricha acuminata, Stein. PL. XLIII. FIGS. 1-3.

Body shortly oblong, about twice as long as broad, widest and broadly
truncate anteriorly, tapering abruptly backwards from the centre, curved
towards the left and terminating in an oblique sharply acuminate point ;
peristome-field extending nearly to the centre of the body, broadly tri-

* "Beitrage zur Morphologic der Oxytrichinen," 'Zeit. Wiss. Zool.,' Bd. xxxi., 1878.
t Vol. I. p. 65.

GENUS KERONA. 763

angular, its reflected border ciliate ; setae of the median ventral rows few in
number, including about five or six in the right and three in the left-hand
row, long, slender, and widely separated ; marginal setae few, distant, and
similar in character to those of the ventral series ; contractile vesicle
developed close to the centre of the left lateral border, exhibiting at
systole short canal-like prolongations ; endoplasts double, median, one
situated in advance of and the other posterior to the terminal border of
the peristome. Length 1-300" to 1-240".
HAB. — Fresh water.

The scattered and irregular disposition of the ventral and marginal setae,
together with their attenuate form, lend to this species an untidy aspect that serves
to distinguish it readily from all other members of the Hypotrichous group. The
irregular development of the stylate appendages is found to extend itself to the large
adoral cirri, which are also comparatively few in number and widely separated.

GENUS II. KERONA, Ehrenberg.

Animalcules free-swimming, persistent in shape, flattened or plano-
convex, subreniform ; possessing no true frontal, ventral, or anal styles,
but in place of these several arcuate rows of short ventral setae ; a row of
similar but longer marginal setae forming a continuous fringe around the
peripheral border ; endoplast usually double ; contractile vesicle single,
spherical, situated near the posterior border of the peristome. Inhabiting
fresh water.

Kerona polyporum, Ehr. PL. XLIII. FIGS. 4 AND 5.

Body kidney-shaped, plano-convex, the anterior end evenly rounded,
the posterior extremity slightly pointed, the right border convex, the left
one deeply indented centrally ; setae of the ventral surface disposed in six
subparallel rows, three of which originating close to the right-hand margin
of the peristome, extend obliquely nearly to the left-hand border of the
posterior half of the body, the other three shorter rows confined to the
anterior body-half; the five hindermost setae of the most posterior row
larger than any of the preceding and apparently representing the five anal
styles of the more normal Oxytrichidae ; peristome-field extending back-
wards nearly to the centre of the body, its inner border ciliate, reflected at
an acute angle, and almost parallel with the outer one ; cilia of the external
or left-hand peristome-border very long and fine, forming with the marginal
setae an almost uninterrupted fringe around the animalcule's body. Length
1-190" to I- 1 20".

HAB. — Fresh water, occurring as an ectoparasite or commensal on
various species of Hydra.

This animalcule is among the first discovered infusorial forms, it having attracted
attention through its frequent occurrence — in company with Trichodina pediculus —
upon the surface of the fresh-water polypes Hydra fusca and H. vulgaris. By many
earlier writers the distinctions between Kerona and Stylonychia have been very
insufficiently denned, but in accordance with the diagnosis of the present genus as

764 ORDER HYPOTRICHA.

amended by Stein and here abbreviated, the distinction is shown to be clear and
decisive. It was originally premised that this species preyed upon the living tissues
of the polype which serves it as a host, the characteristic thread-cells of the higher
organism being frequently found inside it. Such structures, however, are only
incepted with other waste matter thrown off from the surface of the polype's integu-
ment, and in the removal of which its tiny guest undoubtedly plays the role of a
useful scavenger. Other food-matters, such as monads, desmids, and diatoms, are
devoured with equal avidity, and form an important addendum to its customary bill
of fare.

The generic title of Alastor was proposed for this type by Max Perty.

GENUS III. TRICHOGASTER, Sterki.

Animalcules free-swimming, more or less ovate, the entire ventral
surface clothed with minute setose cilia, a few of slightly larger size repre-
senting the frontal, and four or five of similar size the anal series.

Trichogaster pilosus, Sterki.

Body elongate oval ; peristome as in Urostyla, extending backwards to
one-third of the length of the entire body ; adoral cilia short, fine, and very
closely set. Length 1-115". HAB. — Freshwater.

A single example only of the animalcule upon which this genus and species is
founded has been met with by Sterki, and as indicated by that writer,* it more
nearly approaches Urostyla and Kerona in the character and distribution of its ciliary
appendages than any other representative of the Oxytrichidse. Except, indeed, that
the ventral setae were not determined to be distributed in even longitudinal rows,
and that the frontal and anal styles are relatively smaller, there would appear,
in the absence of an illustration or fuller descriptive details, to be little distinction
between this type and the ordinary members of the genus Urostyla.

GENUS IV. UROSTYLA, Ehrenberg.

Animalcules free-swimming, flexible and elastic, ovate or elongate,
rounded at the two extremities, bearing three or more uncinate frontal
styles, five or more rows of median ventral setae, from five to twelve slender
anal styles, and an uninterrupted border of marginal setae ; endoplast
single or multiple ; contractile vesicle usually situated near the left marginal
border. Inhabiting fresh water.

This genus is distinguished from the Oxytrichidae previously enumerated by the
much more luxuriant development of the ventral setse. While in some species
there are not more than five rows of these elements, they very frequently clothe the
entire area of the ventral surface outside the peristome-field.

Urostyla "Weissii, Stein.

Body elongate-elliptical, about three and a half times as long as broad,
widest centrally, gradually tapering towards the two extremities, the ante-
rior end the narrower ; peristome-field forming an acute triangle, extending
to a little beyond the anterior third of the body, its reflected border

* 'Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxxi., 1878.

GENUS UROSTYLA. 765

ciliate, nearly straight; from three to five anteriorly developed ventral
styles, which are supplemented by five even median rows of short ventral
setae ; the marginal setae forming a continuous projecting row ; anal styles
from seven to eight in number ; endoplast ovate, double. Length 1-84".
HAD. — Fresh water.

The Oxytricha urostyla of Claparede and Lachmann is identified by Stein with
this type, from which furthermore it does not seem possible to distinguish the
Oxytricha multipes of the same writers. A variety of this species is reported by
Mereschkowsky from Lake Onega, that is distinguished by the possession of six
instead of five rows of ventral setae.

Urostyla grandis, Ehr. PL. XLIII. FIGS. 6-8.

Body oblong or ovate, very variable in form, when extended about four
times as long as broad, usually widest posteriorly, the anterior extremity
tapering and obtusely pointed ; peristome-field triangular, its reflected
border ciliate, curved inwards at the apical extremity, the intervening
space between the inner and outer borders, and more especially towards the
right, thickly clad with fine vibratile cilia ; the entire angle to the right of the
reflected inner border, or that corresponding with that of the peristome-field
on the left side of this line, beset with the numerous claw-shaped frontal
styles, those nearest the anterior margin being the largest ; median ventral
setae usually developed in even longitudinal rows in such luxuriance as to
completely cover the remaining ventral surface, but occasionally a few only
of these rows represented ; marginal setae rather longer than the ventral
ones, forming an uninterrupted projecting fringe ; from ten to twelve short
anal styles ; endoplast cord-like, breaking up into numerous separate ovate
nodules ; contractile vesicle situated on the left side, near the posterior
angle of the peristome. Length 1-60".

HAB.— Pond water, among Conferva, &c.

Stein attests to having carefully examined innumerable examples of this species
without finding, except in a few isolated instances, any trace of a nucleus or endoplast,
a circumstance which would seem to supply important evidence with respect to the
unessential character of this structure and to its nonconformity with the nucleus of
an ordinary histologic cell. The voracity of this large animalcule is remarkable,
several rotifers, a Coleps, and numerous diatoms and monads representing, as drawn
by Stein, the contents of a single individual's internal parenchyma. Although the
number of rows of the median ventral setae vary considerably in this form, the
location and arrangement of the anterior styles are constant and afford a safe guide
to the recognition of the species, which is moreover the largest known representative
of the Hypotrichous order.

The Oxytricha fusca of both Perty and Claparede and Lachmann is regarded
by Stein as identical with this type.

Urostyla viridis, Stein.

Body lanceolate, three and a half times as long as broad, the two
extremities pointed, the anterior one curved slightly towards the left ;
peristome-field narrow, extending obliquely backwards to about one-third
of the length of the entire body, exhibiting no reflected inner border ; frontal

766 ORDER HYPOTRICHA.

styles large, uncinate, three in number only ; the entire body surface from
the frontal series and the peristome-border backwards covered with closely
approximated longitudinal rows of short ventral setae ; marginal series
similar to the ventral setae but a little longer; five inconspicuous non-
projecting anal setae ; contractile vesicle spheroidal, located near the
centre of the left-hand border ; endoplasts two in number, with attached
endoplastules ; parenchyma usually filled with green chlorophyll-granules.
Length 1-215" to 1-144". HAB. — Fresh water.

The fine even clothing of short setae that covers the entire ventral surface of this
animalcule imparts to it, in conjunction with the flexible character of its body-
substance, an aspect strongly suggestive of a Paramczcium or other Holotrichous
form, and for which, without the detection of the characteristic but not very con-
spicuous frontal and anal styles, it might easily be mistaken.

Urostyla flavicans, Wrz.

Body elongate-elliptical, rounded at each extremity, slightly^ wider
posteriorly, three times as long as broad ; peristome-field extending back-
wards to a distance of about one-third of the length of the entire body, its
reflected border bearing a conspicuous undulating membrane ; frontal
ciliary system consisting of three large uncinate styles and four or five
scattered setae ; ventral setae forming five somewhat oblique longitudinal
rows, a row each side of similar setae constituting the marginal series
which projects beyond the periphery only at the posterior extremity ; anal
styles subequal, eight in number, disposed in an oblique row, the posterior
one only reaching but scarcely projecting beyond the posterior border;
endoplasts ovate, two in number, with attached endoplastules ; contractile
vesicle canal-like, extending along the whole left-hand posterior peripheral
border. Length i-i 10". HAB. — Fresh water.

GENUS V. ONYCHODROMUS, Stein.

Animalcules free-swimming, elliptical, encuirassed ; the cuticular surface
indented but scarcely flattened, peristome extending backwards to the centre
of the body ; ventral surface bearing three anterior oblique rows of claw-
like frontal styles ; from three to four similar central rows of ventral styles,
and five or six anal styles ; outline of body excluding the peristome-field
fringed with an even continuous row of small marginal setae ; endoplasts
multiple ; contractile vesicle single, spherical, situated near the posterior
angle of the peristome. Inhabiting fresh water.

The carapace in the as yet single known species of this genus is described by
Stein as being less indurated than that of Euplotes, but more so than in Stylonychia.
From the last-named type, which it somewhat resembles, it is distinguished by the
linear arrangement of the ventral styles and by the total absence of caudal setae.

Oxychodromus grandis, Stein. PL. XLIII. FIG. 13.

Body elliptical, almost rectangular, about two and a half times as long
as broad, the two lateral margins parallel, occasionally bent slightly inwards

GENUS AMPHISIA. 767

at the centre, the left angle of the anterior margin of the upper surface of
the carapace in adult individuals somewhat obliquely truncate, but in
younger ones symmetrically rounded and overlapping the ventral surface ;
peristome-field triangular, its inner or right-hand border reflected back
along the median line, bearing a band-like undulating membrane and a
row of fine cilia ; three rows of uncinate frontal styles containing collec-
tively from sixteen to twenty-eight elements, the three more anterior of
which are much the largest; from fifteen to twenty-one ventral styles
disposed in the three or four central rows, and from five to six or seven
large, straight, anal styles ; endoplasts ovate, usually four in number, each
having a minute attached endoplastule. Length 1-240" to 1-72".
HAB. — Fresh water.

GENUS VI. AMPHISIA, Sterki.

Animalcules free-swimming, oval or elongate, not encuirassed, soft and
elastic ; the ventral surface more or less flattened, bearing three or four
frontal styles, two or three continuous median rows of ventral setae, and five
or more anal styles ; the marginal setae not projecting at the periphery but
forming two outer rows in close proximity to the ventral setae, with which
they correspond in size and character ; contractile vesicle single, spherical,
situated near the centre of the left-hand lateral border. Mostly inhabiting
salt water.

The representatives of this genus have been recently separated by Sterki * from
the typical members of the genus Oxytricha as here amended, as also from those of
Holosticha, which they still more nearly approach, with reference to the modifica-
tion of their marginal setae. These structures are here removed to a considerable
distance from their normal peripheral position and stationed more or less towards
the centre of the ventral field ; their size and character at the same time correspond
so closely with those of the ventral series that they appear to be merely supple-
mentary rows of the same. A closely identical form and disposition of the marginal
setae occur in certain species of Uroleptus.

Amphisia gibba, Mull. sp.
PL. XLIIL FIG. 15, AND PL. XLIV. FIGS. 15 AND 16.

Body thick, elongate-elliptical, three and a half times as long as broad,
widest in the centre, smaller and equally rounded at the two extremities ;
the peristome-field narrow, fissure-like, exhibiting no reflected border, ex-
tending obliquely to the centre of the anterior third of the body ; ventral
setae forming two even, continuous, closely approximated central rows
the marginal setae similar in character, stationed so close to the ventral setae
as to present the aspect of a third or fourth median series; anal styles
five in number, sub-even, projecting for nearly half their length beyond the
posterior margin. Length 1-144". HAB. — Salt water.

Stein regards this species as corresponding with the Trichoda gibba, and
probably also the T, fceta of O. F. Miiller. An apparent variety of this type,
possessing an additional row of ventral setae, see PL XLIV. Figs. 15 and 16,

* ' Zeitschrift liir Wissenschaftliche Zoologie,' Bd. xxxi., 1878.

768 ORDER HYPOTRICHA.

here retained under the name of Amphisia gibba var. crassa, has received from
Claparede and Lachmann the title of Oxytricha crassa,

Amphisia velox, Quenn. sp.

Body elongate-lanceolate, about four times as long as broad, rounded at
the two extremities, the anterior end somewhat wider and curved slightly
towards the left ; the right border evenly arcuate, the left-hand one bulging
centrally in a gibbous manner; frontal styles uncinate, three in number;
ventral setae fine, forming three even median longitudinal rows ; a row
of similar sized marginal setae developed outside these on each side and
at some distance within the peripheral border ; five small, straight, slightly
projecting anal styles. Length 1-200". HAB. — Salt water.

This species is described by Quennerstedt * under the name of Oxytricha velox.

Amphisia pernix, Wrz. sp. PL. XLIII. FIG. 12.

Body extensile, highly flexible, much thickened, lancet-shaped, about
three times as long as broad, slightly narrower anteriorly; peristome con-
tracted, extending obliquely backwards to the centre of the anterior third of
the body ; frontal styles entirely absent ; ventral setae minute, forming two
closely approximate central rows ; marginal setae equally minute, developed
on the ventral surface at a considerable distance from the periphery, and
presenting the appearance of two supplementary rows of ventral setae ; anal
styles five in number, disposed in an even oblique row, projecting for
nearly half their length beyond the posterior border; contractile vesicle
situated on the left-hand margin at a little distance behind the median line.
Length 1-230". HAB. — Salt water, Baltic Sea.

Described by Wrzesniowski t under the title of Oxytricha (Holosticha) pernix.

Amphisia Kessleri, Wrz. sp.

Body flexible and highly retractile, elongate-lanceolate, flattened, widest
centrally and narrowed towards the two extremities, nearly four times
as long as broad ; four uncinate frontal styles ; two median closely-
approximated rows of minute ventral setae ; marginal setae stationed at a
short distance only from the ventral series, to which they correspond in size
and character ; from twelve to fifteen anal styles, the five posterior only of
which present the characteristic stylate aspect and project beyond the pos-
terior border, the three more posterior of these five set further back than the
other two and curved slightly towards the right, the remaining seven to ten
minute and setose, forming a linear series between the left-hand marginal
and central ventral setae ; minute hispid setae, bordering the peripheral
margin of the anterior two-thirds of the body ; contractile vesicle situated
close to the centre of the left-hand lateral border. Length 1-160".

HAB.— Salt water : Baltic Sea (Wrz.).

* ' Sveriges Infusoriefauna,' Heft iii., 1869.

t ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxix., 1877.

GENUS HOLOSTICHA. 769

The author scarcely concurs in regarding the linear series of minute setae
developed anteriorly to the five large typical anal styles in this species — referred by
Wrzesniowski to the genus Oxytricha — as belonging to the anal group, their contour
and disposition indicating rather their identity with an imperfectly developed
supplementary row of ventral setae. The close affinity of this type to the Amphisia
(Oxytricha) velox of Quennerstedt — from which species, indeed, it would appear to
differ most essentially, the above interpretation of the so-called anal setae being correct,
in the possession of two an.d a half instead of three complete rows of ventral setae —
is fully recognized by its discoverer.

Amphisia multiseta, Sterki.

Resembling A . gibba, but of smaller size ; the ventral region concave,
and bearing as many as ten anal setae.

GENUS VII. HOLOSTICHA, Wrz.

Animalcules free-swimming, not encuirassed, more or less elastic, and
changeable in form, oval or elongate ; the ventral surface bearing three or
four claw-like frontal styles, five or more anal styles, two or three uninter-
rupted median rows of short ventral setae, and a continuous projecting
border of marginal setae ; endoplast double; contractile vesicle single,
spherical, usually occupying a median position close to the left lateral
margin. Inhabiting salt and fresh water.

The genus Holosticha has been instituted by Wrzesniowski * for the reception
of those species hitherto included in the genus Oxytricha, in which the ventral setae
form two or three uninterrupted median rows, in place of the more or less irregularly
scattered plan of distribution which obtains among the typical members of the
last-named generic group. Through the preceding genus, Amphisia, the passage
from Holosticha to Uroleptus and Urostyla is apparently accomplished.

Holosticha mystacea, Stein sp. PL. XLIII. FIG. n.

Body ovate, flattened, nearly three times as long as broad, rounded and
widest posteriorly, the right side convex, the left concave, the upper lip
developed anteriorly into a bluntly rounded point ; peristome-field extending
backwards nearly to the centre of the body, its reflected border arcuate,
distinctly ciliate ; ventral setae forming two irregular, curved, central rows
supplemented anteriorly with a few additional styles ; marginal setae con-
stituting a continuous projecting border, the posterior ones longest ; anal
styles of medium size, not projecting beyond the posterior body margin.
Length 1-190" to 1-144". HAB. — Fresh water.

Identical with the Oxytricha mystacea of Stein.

Holosticha flava, Cohn sp. PL. XLIII. FIGS. 19 AND 20.

Body elongate, flattened and band-like, flexible but not retractile, six or
seven times as long as broad, rounded at both extremities, slightly narrower
at the posterior one ; peristomal ciliary band fringing the anterior border and
extending backwards to a distance of one-third of the length of the body ;

* 'Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxix., 1877.
VOL. II. X

770 ORDER HYPOTRICHA.

a row of fine marginal setae developed along each lateral border; two
median rows of similarly fine ventral setae; an even transverse row of
eight or more slender anal styles projecting beyond the posterior extremity ;
contractile vesicle situated in the posterior third of the body ; colour of
parenchyma yellow or light brown. Length 1-130" to 1-120".
HAB. — Salt water.

This animalcule is recorded by Cohn * as a species of Oxytricha. The same
authority further describes as a variety of this type, under the title of Oxytricha flav a
var. carnea, a flesh-coloured species having twice the breadth and thickness of the
typical form, and which is abruptly truncate and not narrower at the posterior
extremity. The variety in question is further distinguished by the possession of four
longitudinal rows of bright red corpuscles which ornament the parenchyma, as
seen from the ventral surface.

Holosticha rubra, Ehr. sp. PL. XLIII. FIG. 17.

Body highly flexible and retractile, elongate-lanceolate, almost four
times as long as broad, slightly tapering towards and equally rounded at
each extremity ; the peristome-field extending backwards to a distance of
one-third of the length of the entire body ; a transverse row of eight or
nine slender projecting anal styles developed at the posterior extremity ;
parenchyma brick-red, enclosing two central and two marginal longitudinal
rows of minute bright red corpuscles ; contractile vesicle located centrally
at a distance of one-fourth of the body-length from the posterior extremity.
Length 1-140". HAB. — Salt water.

This species, imperfectly figured and described by Ehrenberg and Dujardin
under the title of Oxytricha rubra, was formerly adjudged by Stein and Claparede
and Lachmann to be correctly referable to the genus Uroleptus. The presence
of a well-developed series of anal styles, as recently demonstrated by Cohn, however,
re-establishes its position among the typical Oxytricha, or rather with that offshoot
from the genus with which it is here associated. The author has obtained this
brilliantly coloured marine species from a variety of sources, including salt water
remitted from the Aston Aquarium, Birmingham, by Mr. Thomas Bolton, as also
from among decaying zoophytes collected at St. Heliers, Jersey, and Bangor,
N. Wales. Ehrenberg, its first discoverer, has recorded the occasional occurrence
of the species in such abundance in the North Sea as to communicate a red hue to
the water.

Holosticha oculata, Mereschk. sp. PL. XLIV. FIG. 21.

Body somewhat variable in form, usually subovate or pyriform,
gibbous and inflated in lateral view, about three times as long as broad ;
peristome-field arcuate, extending through one-third of the length of the
body ; frontal styles uncinate, subequal, four in number ; ventral setae very
fine, forming two closely approximated median rows ; marginal setae slightly
larger than the preceding, those on the right side projecting entirely, and
those on left side only partially, beyond the lateral margin ; anal setae five or
six in number, continuous with the left-hand marginal series, projecting
beyond the posterior extremity ; endoplast and contractile vesicle not

* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xvi., 1860.

GENUS PLAGIOTRICHA. 771

observed ; a spheroidal eye-like corpuscle located in the median line near
the anterior extremity, and a similar one of slightly smaller dimensions
near the posterior extremity. Dimensions unrecorded.
HAB. — Salt water : White Sea (Mereschkowsky).

In general form this species is recognized by Mereschkowsky* as closely
approaching the Oxytricha (Amphisia) crassa of Claparede and Lachmann, while the
spheroidal anterior and posterior " eye-like corpuscles " find their equivalent in the
Actinotricha saltans of F. Cohn. In the absence of any other distinctly recognized
endoplast or nucleolar structure, it would seem highly probable, however, that these
so-called eye-like spots are in both cases modified homologues only of this last-named
element. Although not usual among the Hypotricha or other Ciliata, a similar
spheroidal endoplast, embodying a more densely granular central portion and a
hyaline peripheral border, obtains normally throughout the Flagellata.

Holosticha Wrzesniowskii, Mereschk. sp.

Body elongate-oval, rounded and slightly widest posteriorly, more
pointed and curved slightly towards the left anteriorly, a little over three
times as long as broad ; peristome-field narrow, rounded posteriorly, ex-
tending backwards almost to the centre of the body ; six large, subequal,
uncinate frontal styles ; two median rows of fine ventral, and two rows of
similar-sized marginal setae, the elements of the last-named series not
projecting beyond nor reaching the lateral periphery ; anal setae nine in
number, forming an even, slightly projecting posterior row; endoplasts
ovate, two in number ; contractile vesicle located close to the left lateral
border. Length 1-120".

HAB. — Salt-water : White Sea (Mereschkowsky). Motions sluggish.

GENUS VIII. PLAGIOTRICHA, S. K.

(Greek, plagios, oblique ; trichos, hair.)

Animalcules free-swimming, ovate or elliptical, highly elastic ; peristome-
field narrow, arcuate, confined almost entirely to the left-hand antero-lateral
margin, and without any conspicuous reflected inner border ; the ventral
surface bearing eight or more frontal styles, one or more oblique rows of
ventral setae, a projecting fringe of marginal setae, and four or five anal
styles ; two or more slender caudal setae projecting from the posterior
extremity ; endoplasts two in number ; contractile vesicle single, spheroidal,
developed near the left-hand lateral border.

This generic group is instituted for the reception of the Oxytricha strenua of
Engelmann, that species differing from all typical representatives of the genus
Oxytricha as here amended, in the characteristic oblique distribution of the ventral
setae — which thus closely approaches that of Gastrostyla — in the greater number of
frontal styles, and in the possession of hair-like caudal setae ; the peristome-field
likewise presents a well-marked modification. But for the absence of caudal setae,
the Oxytricha affinis of Stein might be also included in the same genus, and is here
temporarily associated with it. Sterki, indeed, as intimated further on, has already

* "Protozoendes nordlichen Russland," 'Archiv fur Mikroskopische Anatomic,' Bd. xvi., 1878.

X 2

772 ORDER HYPOTRICHA.

proposed for that type the generic title of Gonostomum — which name, however,
so closely resembles those of Gonostoma and Gonostomus, already employed to
designate certain genera of Fishes and Mollusca, that the substitution of a new one
appears desirable.

Plagiotricha strenua, Eng. sp. PL. XLIII. FIG. 34.

Body flexible and contractile, elongate-elliptical, about four and a half
times as long as broad, evenly rounded at the two extremities, but slightly
narrower anteriorly ; peristome-field very narrow, confined to the left-hand
lateral border, extending backwards to nearly the centre of the body ; the
adoral cirri very long ; ten uncinate frontal styles ; one and a half oblique
rows of even-sized ventral setae, which are developed backwards from right
to left, the complete row only approaching the left-hand border at a dis-
tance of one-third of the entire length of the body from the posterior
extremity ; four anal styles, and two long fine caudal setae ; a marginal row
of very minute hispid setae developed on the right and left peripheral
borders, these in company with the ordinary marginal series, projecting most
conspicuously towards the posterior extremity ; contractile vesicle located
near the posterior extremity of the peristome ; endoplasts oval, two in
number. Length 1-160". HAB. — Fresh water.

In describing this form as a species of Oxytricha, Engelmann * remarks upon
its general resemblance to Oxytricha (Plagiotricha) affinis, from which it, however,
differs in the number and disposition of the frontal, ventral, and anal styles, and in
the presence of terminal or caudal setae. Although not actually observed, Engel-
mann is inclined to believe that the fine hispid setae that form a second and scarcely
perceptible peripheral fringe are developed also, as in Oxytricha parallela, through-
out the dorsal region. The anal styles in this species appear to be of a softer and
more plastic consistence than is usually found among the Oxytrichidae, two of them,
which are set a little in advance of the others, being flexible and subservient
for ambulatory purposes, after the manner of ordinary ventral setae, which are here
unrepresented towards the posterior extremity of the body.

Plagiotricha (Gonostomum) affinis, Stein sp. PL. XLIII. FIG. 25.

Body elongate-lanceolate, three and a half to four times as long as wide,
narrowed and pointed at each extremity ; peristome-field arcuate, confined
chiefly to the left-hand lateral border, but its posterior extremity bent
abruptly inwards and terminating near the centre of the body ; ventral setae
five or six in number, disposed obliquely from right to left, but not ex-
tending further backwards than the posterior termination of the peristome-
field ; the marginal setae forming an unbroken projecting peripheral fringe,
somewhat larger posteriorly ; anal setae very short and inconspicuous, not
reaching to the posterior extremity of the body ; no caudal setae. Length
1-288" to 1-2 16". HAB. — Marsh water.

This type, representing the Oxytricha affinis of Stein and Gonostomum affinis of
Sterki, is, as previously stated, retained in the present generic group in recognition
of its general conformity, excepting for the absence of caudal setae, with the pre-

• 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xi., 1861.

GENUS EPICLINTES. 773

ceding form, combined with the unsuitability of the generic name with which
Sterki has proposed to associate it. Its distinctness from the ordinary Oxytrichce
is recognized by Stein in his original account of the species ; in this connection
he indicates that the structure of the peristome conforms more closely with that
of Stichotricha secunda, and further remarks that it requires only the greater prolon-
gation of the anterior extremity to transform it into an essentially identical animal-
cule. Additional evidence in support of this suggested relationship, though not
mentioned by Stein, is yielded by the development of the ventral setae, which,
though few in number, exhibit a similar oblique disposition. The short and scarcely
conspicuous anal setae are, as in Plagiotricha strenua, highly flexible and frequently
utilized as ambulatory organs.

GENUS IX. EPICLINTES, Stein.

Animalcules free-swimming, highly flexible and elastic, elongate, divided
as it were into three distinct regions, including an inflated and widest central
region, a narrower anterior, and an elongate posterior or tail-like portion ;
peristome-field extending to the posterior end only of the narrowest
anterior region ; three or four rows of short claw-like frontal styles clothing
the ventral surface of the anterior extremity ; six or seven oblique rows
of short ventral styles or setae developed upon the central part, and two or
more straight parallel rows of short ventral setae upon the elongate caudal
region ; a peripheral row of short marginal setose cilia bordering the caudal
and central parts; terminal anal styles four or five' in number; anal
aperture debouching upon the posterior end of the inflated central portion ;
contractile vesicle single, subcentral or situated near the termination of the
peristome-field. Inhabiting salt water.

The luxuriant development of the ventral setae in this genus approximates it
most closely to Kerona and Urostyla, while in the specially prolonged caudal portion
it exhibits some resemblance to the genus Urokptus. Diesing* has proposed to
associate with the form previously selected by Stein as the type of the present
group, the generic title of Claparedia.

Epiclintes auricularis, C. & L. sp. PL. XLIII. FIGS. 28-30.

Body elongate, about six times as long as broad, the distal region oval,
rounded anteriorly, the central portion elongate-fusiform, about twice the
length of the anterior one, but not much wider ; caudal prolongation band-
like, nearly equalling in length the two preceding portions of the body ;
three oblique rows of short styles developed upon the ventral surface of
the anterior portion, six or seven obliquely parallel rows of setae on the
central part, and three straight parallel rows and a peripheral border of
similar setae on the caodal prolongation. Length of extended body 1-82".

HAB.— Sea water.

This species, which is to be identified with the Oxytricha auricularis of Cla-
parede and Lachmann, is adopted by Stein as the type of his genus Epiclintes,
and is shown by that authority to differ most essentially from all ordinary Oxy-
trichce. The fuller details of this species, as supplied by Stein, he having himself
obtained it on the Baltic sea-board, differ slightly from those originally recorded

* "Revision der Prothelminthen," ' Sitz. d. K. Akad. Wien,' 1866.

774 ORDER HYPOTRICHA.

by the Swiss authorities. Thus, while they have described the central ventral surface
as entirely covered with oblique rows of short setae, no definite number of rows is
mentioned, and in their illustrations they are entirely left out, an omission which
also applies to the marginal setal series of the same region. The position of the
contractile vesicle as given by Claparede and Lachmann is also at variance with
Stein's description, the first-named investigators describing and delineating it as
situated at the posterior end of the central division of the body, while Stein
declares it to occupy that position near the termination of the peristome common to
the majority of the Oxytrichidae.

Epidintes auricularis has been recently met with in tolerable abundance by
Mereschkowsky among algae in the White Sea. According to this observer,* no
less than five or six oblique rows of fine setae are distributed upon the ligulate
anterior prolongation, nine similar rows upon the central or ventral region, and five
parallel rows upon the posterior or caudal prolongation. The marginal series on
either side towards the anterior extremity are represented by Mereschkowsky,
as shown at PI. XLIII. Fig. 30, as taking the form of minute, immotile, bead-like,
or columnar prominences.

Epidintes retractilis, C. & L. sp. PL. XLIII. FIGS. 23 AND 24.

Body elongate, about five times as long as broad, the central portion
much inflated, shortly and broadly fusiform, the anterior region very narrow,
its width equal to one-quarter only of that of the centre part, and about one-
half its length, the posterior or tail-like prolongation ligulate, still narrower
than the anterior one, nearly equal in length to the conjoined preceding por-
tions, highly contractile, and capable of being almost entirely withdrawn into
the more inflated central region ; three nearly straight rows of setae developed
on the anterior part of the ventral surface, those of the central region
numerous, but their actual number and arrangement undetermined ; two
central straight rows developed upon the caudal portion in addition to a
marginal set on each side ; four terminal projecting anal setae. Length
when extended 1-150".

HAB. — Salt water : Norwegian coast (C. & L.).

This animalcule is identical with the Oxytricha retractilis of Claparede and Lach-
mann. While the details of the ventral setae, as given by its discoverers, are not
quite so explicit as might be desired, it is evident that we have here a type closely
allied to Epidintes auricularis, and with which Stein has considered himself justified
in associating it. The remarkable retractile character of the attenuate caudal
extremity, together with the wider expansion of the central part, serve to distinguish
it specifically from the last-named form.

Epiclintes radiosa, Quenn. sp. PL. XLIII. FIGS. 31 AND 32.

Body elongate, about five times as long as broad, central and anterior
portion compressed fusiform, slightly narrowed anteriorly and bearing at its
summit five very large, straight, radiating frontal styles, the posterior or
caudal prolongation narrow or linear, exceeding the entire anterior region in
length ; a single row of marginal setae developed upon each side of the
fusiform anterior and central portions, and a double row of similar setae

* "Protozoan des nordlichen Russland," ' Archiv fur Mikroskopische Anatomic,' Bd. xvi.,
1878.

GENUS STICHOTRICHA. 775

bordering the attenuate caudal prolongation ; contractile vesicle situated
towards the posterior end of the thicker central region. Length 1-250".
HAB. — Salt water.

The abnormal size of the five radiating frontal styles, which in this respect closely
resemble those of Adinotricha saltans, in addition to the less attenuate contour of the
anterior extremity, suffices to distinguish this animalcule from the two preceding types.
As originally described and figured by Quennerstedt,* that authority, apparently
unaware of Stein's new generic appellation, has proposed to confer upon it the title
of Mitra radiosa. Even in the absence of this prior title, Quennerstedt's suggested
name of Mitra could not, however, have been retained, it having been long since
preoccupied for the distinction of a genus of the Mollusca.

GENUS X. STICHOCH^STA, C. & L.

Animalcules free-swimming, elastic but not contractile, the anterior
extremity attenuate and neck-like ; a row of long peristomal cirrose cilia
extending backwards from the apical extremity to the oral aperture which
lies at the base of the neck-like prolongation ; a border of small marginal
setae and two or three ventral rows of similar ventral setae usually present ;
a group of long slender anal styles developed at the posterior extremity.

The author retains as the type of this genus the Stichochata pediculiformis of Cohn,f
which differs essentially from the several specific forms of Stichotricha, with which it
otherwise closely corresponds, through its possession of well-developed anal styles.
The Stichochczta cornutum of Claparede and Lachmann is rightly referred by Stein
to the last-named generic group.

Stichochgeta pediculiformis, Cohn. PL. XLIV. FIGS. 13 AND 14.

Body linear-oblong, rounded posteriorly, flexible but not retractile, the
anterior third produced as a narrower neck-like process, and bearing at its
summit about six long, movable setae, a spiral row of similar setae extend-
ing backwards from these to the oral aperture ; a row of short, fine marginal
setae developed down each lateral border of the ventral surface, and between
these three rows of short ventral setae ; five long, slender anal styles, disposed
in two groups of three and two each, at the posterior extremity ; oral aper-
ture situated at the base of the neck-like prolongation, having issuing from
it a bundle of several long, flexible oral cilia ; contractile vesicles two in
number, one located near the oral aperture and the other towards the
posterior extremity; parenchyma very opaque, through the enclosure of
innumerable fat-like corpuscles. Length 1-250".

HAB. — Salt water. Movements alternately creeping and springing
backwards.

GENUS XI. STICHOTRICHA, Perty.

Animalcules elongate, elastic, and changeable in form, the anterior ex-
tremity attenuate and neck-like ; peristome-field narrow, fissure-like, extend-

* 'Bidrag til Sveriges Infusoriefauna,' Heft ii., 1867.

t " Ncue Infusoricn im Seeaquarium, '' 'Zeit. Wiss. Zool.,' Bd. xvi., 1866.

776 ORDER HYPOTRICHA.

ing from the anterior extremity to about the centre of the body ; cilia of
the external or left-hand peristome-border remarkably long ; no ventral or
anal styles ; merely a peripheral border of fine marginal setae, and one or
more oblique rows of small ventral setae ; endoplast ovate, sometimes
double; contractile vesicle single, spherical, situated near the posterior
angle of the peristome ; often excreting and inhabiting a mucilaginous or
granular sheath or lorica ; the anterior half of the body, when protruded
from this sheath, usually twisted in a screw-like manner. Inhabiting salt
and fresh water.

Stein has proposed to identify as members of this genus the forms referred by
Lachmann to the genus Ch&tospira. As shown, however, on a previous page, such
animalcules are undoubted Heterotrichous forms, closely allied to Follicularia.

Stichotricha secunda, Perty. PL. XLIV. FIGS, i AND 2.

Body highly elastic, lanceolate-fusiform, broadest in the centre, and
tapering to each extremity, the anterior end being the more attenuate ; peri-
stomal or adoral cilia longest at the anterior extremity, gradually diminish-
ing in size as they approach the oral aperture, continued a short way
up the inner or reflected border of the peristome; ventral setae short,
forming a single oblique row ; marginal setae long and slender ; endoplasts
ovate, two in number, having minute attached endoplastules ; contractile
vesicle single, spherical, situated between the two endoplasts close
to the posterior angle of the peristome-field ; animalcules usually secreting
a mucilaginous sheath, which they often vacate to swim freely in the water ;
the anterior half of the body, when extended from this tube, twisted to the
right in a screw-like manner. Length 1-190" to 1-120".

HAB. — Fresh water, among Sphagnum,

Stichotricha cornuta, C. & L. sp. PL. XLIV. FIG. u.

Body somewhat flask- or bottle-shaped, its apex attenuate, bearing
a single, long, straight, acerate spine or seta ; cilia of the peristome
shortest anteriorly, increasing in length as they approach the oral aper-
ture ; marginal setae continued up the left side of the peristome as very
long hair-like setae ; three parallel oblique rows of fine ventral setae developed
in addition to the peripheral border of larger marginal setae ; endoplasts
oval, two in number. Length 1-300". HAB. — Fresh water.

This species is identical with the Stichochata cornuta of Claparede and Lach-
mann. While evidently referable to Perty's genus Stichotricha, as more recently
amended by Stein, it must certainly not be merged with Stichotricha secunda, as that
authority has proposed, and from which it is shown, by Stein's own description and
illustrations, to differ in all essential specific details. In attempting their amalgama-
tion, Stein has sought to demonstrate that a renewed examination of Stichotricha
secunda has revealed to him the existence of the apical spine, of three rows of ven-
tral setae, and of the long marginal elements on the left border of the attenuate
anterior extremity, characteristic of Claparede and Lachmann's type. Accrediting
Stein, however, with that faithfulness of description and delineation that usually

GENUS SCHIZOSIPHON. 777

characterizes his diagnoses, it is difficult to assume otherwise than that he had in
the second instance the actual type of the last-named authorities, and not his original
Stichotricha secunda under examination.

For the advantage of further comparison the drawings of the two forms, as repre-
sented respectively by Stein and by Claparede and Lachmann, are reproduced in
Plate XLIV. The building up by Stichotricha cornuta of an artificial mucilaginous
domicile has not so far been determined.

Stichotricha aculeata, Wrz. PL. XLIV. FIG. 3.

Body elongate-lanceolate, about four and a half times as long as broad,
tapering from the centre towards the posterior as well as towards the nar-
rower anterior region ; the apical extremity of the anterior portion bearing
two stout, slightly curved, uncinate styles, each lateral border of this
region fringed with very long, fine, hair-like setae ; peristomal cilia largest
anteriorly, gradually diminishing in size as they approach the oral aperture,
continued as finer cilia up the right-hand or reflected inner border ; two
oblique rows of ventral setae and an even border of similar-sized marginal
setae ; contractile vesicle situated immediately below the oral aperture ;
endoplasts ovate, two in number, with attached endoplastules. Length
1-375" to 1-250." HAB. — Fresh water, among Lemnceand Sphagnaceae.

. The two apical styles, double anterior fringe of fine hair-like setae, and two
instead of three oblique rows of ventral setae, distinguish this form from
Stichotricha cornuta. The species was obtained by Wrzesniowski * in the neighbour-
hood of Warsaw, and is reported to pass an entirely free-swimming existence. When
swimming the two anterior style-like processes are vibrated with such rapidity as to
be scarcely visible.

Stichotricha remex, Hudson sp. PL. XLIV. FIGS. 9 AND 10.

Animalcule building and inhabiting a long, slender, cylindrical, brown-
coloured tube, whose height may equal or exceed three or four times the
length of the body ; body lanceolate, its anterior half when extended from
the tube twisted spirally ; the cilia at the anterior or apical extremity of
the adoral fringe the longest. Length of body 1-90", of the cylindrical
tube 1-20".

HAB. — Pond water, often clustered in groups on the leaves of Anacharis
and other water-plants.

This animalcule is figured and described by Dr. C. T. Hudson in the ' Monthly
Microscopical Journal ' for October 1875, under the title viArchimedea (Chcetospira ?)
remex. So far as it is possible to decide from his representations, reproduced at
PL XLIV. Figs. 9 and 10, and accompanying account given of the character and
disposition of the cilia upon the surface of the body, it would appear to correspond
most closely with Stichotricha secunda. That it is not a Chcetospira, as was to some
extent premised by its describer, is made evident by the setose character of the cilia
and their restriction to the ventral aspect. A single spheroidal contractile vesicle
was observed near the base of the adoral fringe, and adjacent to this, on the right
side, an anal aperture. With respect to the habits of this infusorium Dr. Hudson
is more explicit. As a rule it resides at the top of its slender brown-coloured tube,
occasionally backing down to the bottom of it, or if suddenly alarmed, as by a tap

* " Infusorien aus der Umgebung von Warschau," ' Zeit. Wiss. Zool.,' Bd. xx., 1870.

778 ORDER HYPOTRKHA.

on the table, flashing out of sight after the manner of a serpula with the rapidity
of lightning. Confidence being restored, it once more makes its appearance at the
' entrance of its abode, at first protruding a short distance only from the aperture, main-
taining a perfectly straight position, and with its frontal cilia quivering. No further
cause of alarm arising, the entire anterior half of the body is now thrust out and
twisted into the characteristic screw-like form depicted in the accompanying figures.
The tubes formed by these animalcules are described as being of very frail consistence,
rarely retaining their inhabitants for more than four days, and then quickly dropping
to pieces ; the animalcules are also exceedingly restless in captivity, deserting their
abodes and swimming freely in the open water without any apparent provocation.
The fact that the tubes are built by the animalcules themselves, and are not the
vacated and re-inhabited residences of Rotiferae or other tube-forming organisms, was
amply proved by the preservation of very young individuals possessing at the time
tubes whose construction had only just commenced, but which after the lapse of two
days exhibited all the characters and proportions of the adult types.

Through Mr. Thomas Bolton the author received, in the years 1871-2, from the
neighbourhood of Stourbridge, Worcestershire, the tubes, deserted en route, of an,
animalcule apparently identical with this species, and upon which, guided only
by Mr. Bolton's sketches, and in the absence of any positive evidence respecting the
character of the cuticular or ventral cilia, he provisionally conferred the name of
Chatospira cylindracea. This manuscript title is referred to by Mr. Bolton in the
'Midland Naturalist' for 1878, but the specific one, should the animalcule be a
veritable Stichotricha, must necessarily give way to the earlier published, though
later suggested, name employed by Dr. Hudson.

Stichotricha marina, Stein.

This species is briefly alluded to by Stein* as closely resembling
5. secunda, but is of larger size, inhabits sea water, and exhibits a slight
difference in the arrangement of the ventral setae.

GENUS XII. SCHIZOSIPHON, S. K.

(Greek, schizo, to cleave ; siphon, tube.)

Animalcules structurally resembling those of Stichotricha, but forming
social colonies which build up by excretion a compound branching tube or
zoothecium.

This new genus is established by the author for the reception of the interesting
type recently figured and described by Dr. Ernest Gruber* under the title of
Stichotricha socialis ; its distinctive • feature, which separates it indeed from all
previously known Hypotricha, is manifested in the habit the animalcules have of
constructing by exudation a ramifying colonial habitation or zoothecium. In this
connection they may be said to occupy a position with relation to Stichotricha
corresponding with that which subsists between such compound types as Epistylis
or Carchesium and the simple genus Vorticella. ^

Schizosiphon socialis, Gruber sp. PL. XLIV. FIGS. 4-8.

Body elongate-ovate, obliquely truncate and attenuate anteriorly ; the
peristomal cilia longest at the anterior extremity, diminishing in size as
they approach the oral aperture, and continued up the interior or left
peristomal border, surmounted apically by a tuft of three or four distinctly

* 'Infusionsthiere,' Abth. ii., 1867.

t 'Zeit. Wiss. Zool.,' Bd. xxxi., 1879; also translation in 'Journal of Royal Microscopical
Society,' April 1880.

GENUS UROLEPTUS. 779

differentiated setose cilia ; ventral cilia disposed in four oblique spiral
parallel lines; a few scattered caudal setae developed at the posterior
extremity, and a row of similar marginal setae developed along the right-
hand border of the anterior body-half ; endoplasts axial, two in number,
with attached endoplastules ; contractile vesicle single, subcentral ; com-
pound tube or zoocytium pendulous, of granular consistence, branching in
an even dichotomous manner. Length of zooids 1-120", of branching
zoothecium 1-15" to i-io". HAB. — Fresh water.

GENUS XIII. STRONGYLIDIUM, Sterki.

Animalcules free-swimming, elongate, soft and elastic, bearing about
six stout frontal styles, two oblique rows of ventral setae, three caudal,
but no anal setae ; the dorsal surface clothed with very fine, short, im-
motile, hispid setae.

A single species, Strongylidium crassum, is briefly referred to by Sterki,*
as corresponding in general contour with Uroleptus piscis, but having a thicker,
almost cylindrical body, which is twisted upon its axis towards the left. The
large number of frontal styles, and the presence of caudal setae, would appear to be
the chief grounds upon which a new genus has been established for its reception.

GENUS XIV. UROLEPTUS, Ehrenberg.

Animalcules free-swimming, elongate, highly elastic, but maintaining the
same general contour; the posterior extremity usually produced in an
attenuate, tail-like manner ; the ventral surface bearing three or four anterior
or frontal styles, and usually two closely approximated median lines of ventral
setae ; a marginal border of similar setae continuous with or situated at a
little distance within the periphery ; no anal styles ; endoplast double or
multiple ; contractile vesicle single, spherical, located towards the posterior
termination of the peristome. Inhabiting fresh water.

Uroleptus musculus, Mull. sp. PL. XLIII. FIG. 14.

Body but little elastic, elongate-pyriform, three times as long as broad,
cylindrical anteriorly, dilated to its greatest width posteriorly, abruptly
rounded off in that region, and ending in a short, conical, tail-like termina-
tion ; the anterior end curved slightly to the left, the posterior one to the
right ; peristome-field extending backwards to about one-third of the length
of the entire body, its reflected border ciliate ; the border of marginal setae
encroaching considerably on the median area, projecting beyond the peri-
phery at the posterior extremity only ; central rows of ventral setae two in
number, produced to the extremity of the posterior termination ; anal
aperture located close to the base of the conical posterior termination;
contractile vesicle adjacent to the centre of the right lateral border.
Length 1-195" to 1-120".

HAB. — Fresh water, among Callitricha and other aquatic plants.

* " Morphologic der Oxytrichinen," ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxxi., 1878.

780 ORDER HYPOTRICHA.

This species represents the relatively shortest and widest member of its genus, all
other known forms being characterized by their exceedingly attenuate outlines. It
was first described by O. F. Miiller under the title of Trichoda musculus, being
afterwards referred to the present genus by Ehrenberg.

Uroleptus gibba, C. & L. sp.

Body straight, lanceolate, three and a half times as long as broad,
rounded anteriorly, somewhat pointed posteriorly ; possessing four rows
of ventral setae and a continuous projecting peripheral or marginal series,
whose separate elements are rather the longest posteriorly. Length 1-250".

HAB. — Fresh water.

Stein has referred to this species, described by Claparede and Lachmann under
the title of Oxytricha gibba, as probably belonging to the genus Uroleptus, and finding
its nearest ally in U. musculus. The number of rows of ventral setae distinguish
it, however, from this and all other known representatives of the genus.

Uroleptus piscis, Mull. sp. PL. XLIII. FIG. 21.

Body exceedingly elastic and somewhat variable in shape, broadly linear-
fusiform or band-like, from six to eight times as long as broad ; the anterior
end rounded, curved slightly to the left ; widest in the centre, tapering
gradually towards the posterior extremity, and thence terminating in a
strap-shaped, bluntly pointed, tail-like prolongation, which is curved some-
what towards the right ; peristome-field extending backwards to about
one-fourth of the length of the whole body, its reflected border ciliate ;
marginal setae projecting beyond the peripheral border throughout its
length, considerably longer around the tail-like posterior prolongation ;
median rows of ventral setae two in number, not produced into the
tail-like region ; contractile vesicle located close to the left-hand margin,
opposite or even anterior to the posterior angle of the peristome ; endo-
plasts two in number, posterior to the contractile vesicle. Length of body
1-48". HAB. — Fresh water.

This animalcule is identical with the Trichoda piscis of Miiller, the Uroleptus piscis
and Oxytricha caudata of Ehrenberg, and with the Oxytricha caudata of Claparede
and Lachmann.

Uroleptus ratulus, Stein. PL. XLIII. FIG. 33.

Body persistent in shape, linear-fusiform, about ten times as long as
broad; the anterior end rounded, curved slightly to the left, tapering
gradually from the centre and terminating in a long, thin, acutely pointed
tail ; peristome-field extending backwards to one-fifth of the length of
the whole body, very narrow, its reflected border unciliate ; the marginal
setae projecting throughout the periphery, very little longer at the posterior
or tail-like portion ; the central ventral setae forming two rows, not pro-
duced to the extremity of the caudal appendage ; contractile vesicle
developed near the left lateral margin, at a considerable distance from
the termination of the peristome ; endoplasts two in number, situated at
equal distances one in front of the other behind the contractile vesicle.
Length 1-60". HAB. — Fresh water.

GENUS PLE U ROT RICH A . 781

Uroleptus violaceus, Stein. PL. XLIII. FIG. 18.

Body persistent in shape, broadly linear, flattened, five to six times as long
as broad; the anterior extremity widest, truncate, its corners rounded,
gradually tapering towards the truncate and rounded posterior end, the
width of which, at its termination, is equal to nearly half that of the
anterior one ; peristome-field developed backwards to about one-fifth of the
length of the body, its reflected border arcuate, unciliate ; marginal setae
projecting beyond the periphery, lengthening as they approach the pos-
terior extremity; median rows of ventral setae two in number, produced
nearly to the extremity of the tail-like termination ; position of contractile
vesicle and endoplasts similar to that of U. ratulus ; the parenchyma
usually enclosing numerous brilliant violet granules. Length 1-160" to
i-ioo". HAB. — Fresh water.

Uroleptus mobilis, Eng. PL. XLIII. FIGS. 9 AND 10.

Body flexible, elongate-linear, cylindrical, about twelve times as long as
broad, attenuate posteriorly and terminating in an abruptly truncate point ;
peristome exceedingly narrow, extending backwards to about one-ninth of
the length of the entire body, its inner or reflected border bearing an undu-
lating membrane ; frontal styles uncinate, three in number ; ventral setae
undescribed ; marginal setae long, fine, and evenly developed, but widely
separated ; contractile vesicle situated at a distance of one-third of the length
of the body from the anterior extremity; endoplasts elongate oval, six
in number. Length 1-75". HAB. — Fresh water.

This species may be distinguished from U. ratulus by the abruptly truncate contour
of the tail-like posterior extremity, the longer and more scattered marginal setae, and
by the comparatively shorter peristome-field.

Uroleptus agilis, Eng.

Body flexible but persistent in form, elongate-lanceolate, four or five
times as long as broad, widest centrally, tapering to the two extremities,
the posterior one slightly the narrower ; peristome-field moderately wide,
extending backwards to a distance of about one-fifth of the length of the
body ; frontal styles four in number, bearing immediately behind them
three antero-ventral setse, a few additional ventral setae developed in the
centre of the body ; marginal setae set far inwards, projecting beyond the
periphery only at the posterior extremity of the body, the hindermost setae
of this series much larger than the preceding, forming a terminal projecting
fascicle ; contractile vesicle situated near the centre of the left lateral border ;
endoplasts elongate-ovate, two in number. Length 1-300" to i-ioo".

HAB. — Fresh water.

As remarked by Engelmann,* this species intimately connects the two genera

* • Zeit. Wiss. Zool.,' Bd. xi., 1861.

7§2 ORDER HYPOTRICHA.

Uroleptus and Oxytricha, the form of the body according with the former, and the
character and disposition of the setae corresponding more closely with those of the
last-named genus.

GENUS XV. STYLONETHES, Sterki.

Animalcules free-swimming, widest and rounded posteriorly, narrowed
anteriorly, more or less thick or inflated ; the anterior half of the frontal
region bearing numerous, from fifteen to twenty, scattered frontal styles or
setae ; two rows of ventral setae ; no anal styles ; the marginal setae forming
a continuous projecting border.

A single form is referred by Sterki * to this genus under the name of Stylonethes
tardus, but no specific description or illustration of it has as yet appeared. So far as
it is at present possible to determine, this single type connects the two genera
Holosticha and Uroleptus.

GENUS XVI. ALLOTRICHA, Sterki.

Animalcules free-swimming, soft and elastic, more or less ovate ; frontal,
ventral, anal, and marginal setae corresponding with those of Oxytricha
or Stylonychia, added to which are two supplementary rows of external
ventral setae as in Pleurotricha; structure of peristome, movements, and
general appearance coinciding with those of Urostyla.

A single species, yet awaiting description, is referred to this genus by Sterki, f
under the title of A. mollis.

GENUS XVII. PLEUROTRICHA, Stein.

Animalcules free-swimming, persistent in form, elongate or elliptical,
with from five to eight claw-like frontal styles, the three anterior of which
are usually most conspicuously developed ; four or five scattered ventral
styles and in addition to these one or more supplementary rows of smaller
ventral setae ; anal styles five or six in number, forming two distinct groups ;
peristome-field not extending to the median line, its reflected border ciliate,
usually bearing a conspicuous, band-like, undulating membrane ; endoplas't
ovate, sometimes multiple ; contractile vesicle situated near the posterior
angle of the peristome. Inhabiting fresh water.

While in its general characters this genus closely corresponds with Stylonychia, its
members are distinguished from the latter by the absence of caudal setae, by the
more luxuriant development of the ventral setae, and by the separation of the anal
styles into two distinct groups.

Pleurotricha grandis, Stein. PL. XLIII. FIG. 26.

Body elliptical, about twice as long as broad, peristome-field not extend-
ing to the median line, its reflected inner border ciliate, bent round towards
the opposite one at its distal extremity, the central area of the peristome-
field bearing a conspicuous line of endoral cilia ; the four or five sub-central
ventral uncini supplemented on each side by two parallel rows of smaller

* 'Zeitschrift fur Wissetischaftliche Zoologie,' Bd. xxxi., 1878. t Ibid.

GENUS GASTROSTYLA. 783

ventral setae ; the two right-hand anal styles removed towards the posterior
extremity, and projecting to a considerable distance beyond its margin ;
contractile vesicle developed close to the posterior angle of the peristome-field.
Length of body 1-120" to 1-60". HAB. — Fresh water, among Callitricha.

Pleurotricha lanceolata, Ehr. sp. PL. XLIII. FIG. 27.

Body elongate-lanceolate, two and a half times as long as broad, pointed
posteriorly, the anterior end curved slightly towards the left ; the supple-
mentary ventral setae less developed than in the preceding species, forming
a single complete and the half of a second row only on the right-hand
side of the larger ventral uncini, no such setae developed on the opposite or
left-hand side of the ventral area ; anal and ventral styles, peristome-field,
and other details, as in P.grandis. Length 1-144" to 1-84".

HAB. — Fresh water, among aquatic plants.

This species is identified by Stein with the Stylonychia lanceolata of Ehrenberg.
The accompanying figure is illustrative of the encysted condition of the animalcule
as delineated by the first-named authority.

Pleurotricha echinata, C. & L. sp. PL. XLIII. FIG. 22.

Body elongate-lanceolate, rather more than four times as long as broad,
the extremities rounded, the right side nearly straight, the left one gibbous ;
peristome-field produced backwards to a little more than one-quarter of
the length of the whole body ; one row of ventral setae developed on each
side of the five scattered ventral uncini ; marginal setae forming a continuous
peripheral fringe, long, slender, situated far apart from one another, and
projecting at a right angle from the cuticular border ; anal styles five in
number, forming two groups, the two right-hand styles projecting posteriorly
and directed to the right ; contractile vesicle situated near the centre of
the left-hand lateral border. Length 1-275".
, HAB. — Fresh-water ponds, in the Berlin Zoological Gardens.

This animalcule, which is described by Claparede and Lachmann under the title
of Stylonychia echinata, is referred with some doubt to the present genus. It is not
improbable that the peripheral fringe of fine hair-like setae are of a supplementary
character, and homologous with the minute hispid setae which occur in a similar
position in Stylonychia mytilus and other Oxytrichidae, and in which case the two
rows of so-called ventral setae represent the true marginal series in this instance set
far inwards as in Amphisia. Should this premise prove correct, this form will
furnish the type of a new generic group to which, with reference to the characteristic
marginal fringe of setae, the title of Mesotricha might be appropriately applied.

GENUS XVIII. GASTROSTYLA, Engelmann.

Animalcules free-swimming, persistent in shape, elongate or elliptical ;
frontal styles usually five or six in number, the three anterior being most con-
spicuously developed ; ventral setae forming a single oblique row extending
from the right-hand border towards the anal styles, occasionally supplemented
by a few isolated central uncini ; anal styles five or six in number ;

784 ORDER HYPOTRICHA.

marginal setae forming a continuous border, usually longest posteriorly;
peristome-border reflected, bearing an undulating membrane; endoplasts
two or four in number.

This genus, as established by Engelmann,* is to be distinguished from Pleuro-
tricha by the single oblique series of ventral styles, which here takes the place of the
several supplementary rows that characterize the last-named genus.

Gastrostyla Steinii, Eng. PL. XLIII. FIG. 16.

Body elliptical, rounded at each extremity, slightly widest posteriorly,
nearly three times as long as broad ; peristome-field extending backwards
to a distance of about one-third of the length of the entire body, its reflected
border bearing a conspicuous undulating membrane ; frontal styles six in
number ; about three scattered ventral styles developed in addition to
the oblique linear series ; anal styles four or five, forming a single oblique
row, not projecting beyond the posterior extremity ; marginal setae coarse,
increasing in length as they approach the hinder extremity of the body ;
contractile vesicle situate close to the posterior angle of the peristome ;
endoplasts ovate, four in number, arranged in a line down the centre of
the body, each with a minute laterally attached endoplastule. Length
1-150" to 1-75". HAB. — Fresh water.

Gastrostyla setifera, Eng. sp.

Body elongate lanceolate, slightly gibbous, widest centrally, equally
narrowed at the two extremities, about two and a half times as long as
broad ; peristome-field extending backwards nearly to the centre of the
body, its reflected border bearing a band-like undulating membrane, and its
central area supplemented by a conspicuous median line of endoral cilia ;
frontal styles five in number, uncinate, the three anterior being the largest ; an
oblique row of central and a few scattered ventral styles ; anal styles five in
number, forming two groups of three and two each, the latter only projecting
beyond the posterior border; marginal setae coarse, longest posteriorly;
contractile vesicle situated near the centre of the left-hand lateral border ;
endoplasts two in number, ovate. Length 1-80". HAB. — Fresh water.

This species has been described by Engelmann under the title of Pleurotricha
setifera, but, as shown by his illustration, the character and arrangement of the
ventral styles coincide so completely with those of Gastrostyla Steinii, that it
appears desirable to refer it to the same genus. The four or five additional frontal
setae mentioned by Engelmann would appear to correspond with the anterior setae of
the oblique ventral row, as none separate from these are exhibited in his drawing,
while at the same time the oblique row is not referred to in the text, the ventral
styles being described merely as five or six in number. Diesing,t premising that
there is a separate group of frontal setae, in addition to the five uncinate styles and
oblique ventral row, has proposed for this type the new generic title of
Nothopleurotricha.

SterkiJ intimates that he has encountered two new large-sized species

* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xi., 1861.

t ' Revision der Prothelminthen,' 1866.

j ' Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxxi., 1878.

GENUS OPISTHOTRICHA. 785

of this genus, both distinguished from the preceding by the thickened or
inflated contour of their bodies and conspicuous pre-oral and endoral ciliary
fringes ; full details of these types, as also their specific titles, await publication.
The Oxytricha mystacea of Stein, with its central double row of Ventral setae,
is apparently regarded by Sterki as referable to the present genus, but except for the
somewhat irregular disposition of the component setae of these rows, it agrees in all
essential points with the ordinary members of the genus Holosticha of Wrzesniowski,
to which it is here relegated.

GENUS XIX. OPISTHOTRICHA, S.K.

(Greek, opisthen, behind ; thrix, hair.)

Animalcules free-swimming, soft and elastic, ovate or elliptical ; frontal,
ventral, and anal styles as in Oxytricha, but bearing in addition a variable
number of tail-like caudal setae at the posterior extremity.

This genus is here instituted for the reception of the Oxytricha parallela of Engel-
mann, and all other types corresponding with that form in the possession of several
caudal setae in addition to the ordinary characteristics of the genus Oxytricha. In
this respect it exhibits the same relationship to the last-named genus as is presented
by Stylonychia in comparison with Histrio. Although the single species quoted can
alone be referred at present to this new generic group, Sterki records his acquaint-
anceship with several species of Oxytricha sharing the same characteristics, the
specific descriptions of which, however, still await publication.

Opisthotricha parallela, Eng. sp. PL. XLIII. FIGS. 35 AND 36.

Body elastic and contractile, elongate-elliptical, bluntly rounded at
each extremity, about four times as long as broad ; peristome-field mode-
rately broad, extending backwards to a distance of about one-quarter of the
entire length ; five uncinate and three setose frontal styles ; five scattered
central ventral setae and a continuous peripheral border of large, scarcely
projecting marginal setae, the four most posterior of these so greatly exceed-
ing the others in length as to constitute a distinct caudal series ; anal styles
five in number, projecting but slightly beyond the posterior border; several
longitudinal rows of very fine, hair-like or hispid setae developed on the
dorsal surface ; contractile vesicle situated close to the centre of the left-
hand border; endoplasts ovate, two in number. Length 1-125".

HAB. — Fresh water.

The great development of the fine dorsal setae constitutes a conspicuous feature
of this species, in addition to the presence of the four terminal or caudal setae. But
for the agreement in number and disposition of the ventral setas with those of the
ordinary Oxytrichce, this animalcule exhibits many points of affinity with Plagiotricha
strenua.

Opisthotricha similis, Eng. sp.

Body elliptical, equally rounded at each extremity ; the marginal setae
stationed close to and projecting beyond the lateral borders, two long sup-
plementary caudal setae developed at the posterior extremity ; other details
agreeing with those of Oxytricha pellionella. Length 1-300".

HAB. — Fresh water.

VOL. II.

786 ORDER HYPOTRICHA.

GENUS XX. OXYTRICHA, Ehrenberg.

Animalcules free-swimming, not encuirassed, more or less flexible and
elastic, ovate or elliptical ; bearing three or four uncinate and usually a few
supplementary setose frontal styles, five or more anal styles, a continuous
border of projecting marginal setae, and only a few, mostly five, scattered or
isolated ventral setae ; endoplasts two in number ; contractile vesicle single,
spherical, situated near the centre of the left-hand lateral border. Inhabit-
ing salt and fresh water.

The genus Oxytricha, as amended in accordance with the foregoing diagnosis,
differs materially from the generic group bearing the same name as first originated by
Ehrenberg and included in all later works on the subject of the Infusoria. In
accordance with the recently published views of Wrzesniowski and Sterki, all those
forms characterized by the presence of two or more uninterrupted median rows of
short ventral seta? have been eliminated and referred to the new genus Holosticha,
from which latter again have been separated a third generic group bearing the
name of Amphisia, differing in the structure and disposition of the marginal setae,
which are scarcely to be distinguished from those of the ventral series. In the
considerable assemblage of forms yet remaining to represent the genus Oxytricha the
number and disposition of the few isolated ventral seta? correspond essentially with
the formula common to Stylonychia and Histrio, and from the latter of which two
genera Oxytricha is to be distinguished only by the soft and elastic instead of more or
less indurated character of the cuticular investment. The author has additionally
separated in this volume, as the type of the new genus Plagiotricha, the Oxytricha
strenua of Engelmann, which differs from all typical Oxytrichce in its possession of
two bristle-like caudal setae and an arrangement of ventral setae which most nearly
approaches that of Gastrostyla.

Oxytricha pellionella, Mull. sp. PL. XLV. FIGS. 3-5.

Body moderately elastic, not contractile, linear-elliptical, rather over four^
times as long as broad, widest in the centre, the two extremities equally
rounded ; peristome-field narrow, triangular, extending to the centre of the
anterior third of the body ; no conspicuous reflected inner border ; ventral
setae represented by five irregularly disposed styles and setae only ; marginal
setae stationed at some distance from the periphery, the posterior ones only
projecting beyond its hinder border ; anal styles five in number, long and
stout, recurved towards the left, sometimes uncinate at their extremities,
and all projecting to a considerable distance beyond the posterior margin.
Length 1-288". HAB.— Fresh water.

This type corresponds with the Trichoda pellionella of O. F. Miiller.

Oxytricha ferruginea, Stein sp.

Body linear-oblong, about five times as long as broad, rounded and
widest posteriorly, the anterior end bluntly pointed, curved somewhat
obliquely towards the left ;. peristome-field wide, extending backwards to
the centre of the anterior third of the body, its inner border reflected to a
considerable distance and curved inwards to the left, bearing a distinct un-
dulating membrane ; median ventral setae represented by a few irregularly
disposed styles; marginal setae uninterrupted, projecting throughout the

GENUS OXYTRICHA. 787

periphery ; anal styles large, but not reaching to the posterior extremity of
the body. Length 1-144". HAB. — Fresh water.

Oxytrichafallax, Stein. PL. XLV. FIG. 7.

Body ovate, flattened, two and a half times as long as broad, rounded
and widest posteriorly, tapering towards and bluntly pointed at the
anterior end ; peristome-field wide, extending backwards nearly to the
centre of the body ; its reflected inner border ciliate, curved to the left at
its anterior extremity ; ventral setae represented by a few scattered styles ;
marginal setae forming a continuous projecting fringe, longest towards the
posterior extremity ; three only of the anal styles produced beyond the
posterior margin. Length 1-168" to 1-144". HAB. — Fresh water.

Oxytricha platystoma, Ehr. sp. PL. XLV. FIGS. 8 AND 9.

Body elongate, obovate, two and a half times as long as broad, widest
towards the anterior extremity, gradually tapering thence to the rounded
but narrowest posterior end ; peristome-field. deeply excavate, helicoidal,
not extending to the centre of the body, its reflected inner border curved
inwards to the left in a spiral manner, bearing a row of fine pre-oral cilia
and an undulating membrane ; ventral setae five in number, marginal series
forming an uninterrupted, prominent peripheral fringe, twe of the anal styles
only projecting a slight way beyond the posterior body-margin.

This species is identical with the Oxytricha platystoma of Ehrenberg and Stein.
The elegant helicoidal contour of the peristome-field distinguishes it from all the
preceding species of this genus, and is at the same time so deeply cut as to show
clearly through from the dorsal aspect. Diesing * has proposed to separate both this
and O. ferruginca from the ordinary Oxytricfup, and to create for them the new
generic title of Steinia ; but in face of the more comprehensive partitioning of the
genus Oxytricha by Wrzesniowski and Sterki, as here adopted, the further generic
separation of these two types does not at present appear desirable.

Oxytricha micans, Eng.

Body highly contractile ; anal styles slender, eight to ten in number, those
towards the right-hand side being largest and most prominent ; shape of the
body and disposition of the other styles and setae agreeing with that of
Oxytricha pellionella. Length 1-300". HAB. — Fresh water.

Oxytricha seruginosa, Wrz. PL. XLIV. FIGS. 19 AND 20.
Body very flexible, slightly contractile, elongate-elliptical, about three
and a half times as long as broad, the two extremities rounded, the anterior
one slightly narrower and curved somewhat to the left ; pe'ristome-field
extending backwards to a distance of a little over one-fourth of the length
of the entire body ; three uncinate frontal styles and three or four frontal
setae ; ventral setae five in number, two situated immediately behind the
peristome, one central, and the other two adjacent to the anal styles ; anal
styles five in number, slender, and not projecting beyond the posterior

* ' Revision der Prothelminthen,' 1866.

Y 2

788 ORDER HYPOTRICHA.

border ; marginal setae set within the periphery, and excurrent only at the
posterior extremity ; a supplemental border of very short, hair-like, or hispid
setae projecting at right angles down each lateral margin ; endoplasts two in
number, ovate ; contractile vesicle situated close to the left-hand border
a little in advance of the median line. Length 1-200" to 1-150".

HAB. — Fresh water ; parenchyma usually enclosing rust-coloured
granules.

This and the two following species are described by Wrzesniowski in his account
of the Infusoria of Warsaw.*

Oxytricha macrostyla, Wrz.

Body flexible, but not contractile, elongate-lanceolate, about five times
as long as broad, the anterior extremity rounded, gradually tapering from
the centre, narrowest and somewhat pointed posteriorly ; peristome-field
extending backwards to a distance of about one-quarter of the length of the
entire body, furnished with a double, lip-like process ; possessing seven or
eight uncinate frontal styles, five ventral styles, disposed quincuncially as
in O. (zruginosa, and five large, stout, incurved anal styles, which do not
project beyond the posterior extremity; marginal setae forming an even,
projecting lateral border, increasing in length and prominence towards the
posterior extremity ; a supplemental border of fine hispid setae developed
down the right and left peripheral margins ; contractile vesicle situated
close to the left-hand margin, in front of the median line ; endoplasts two
in number, ovate. Length 1-200". HAB. — Fresh water.

Oxytricha sordida, Wrz.

Body lanceolate, about three and a half times as long as broad, the
right-hand border convex, the left one indented, the anterior extremity
narrower and curved slightly towards the left ; bearing three anterior uncinate
and three more posterior setose frontal styles ; five scattered ventral setae,
and four or five slender, projecting anal styles ; marginal setae forming a
continuous peripheral border, longest towards the posterior extremity ;
contractile vesicle situated close to the centre of the left lateral border.
Length 1-200". HAB. — Fresh water.

Oxytricha scutellum, Cohn. PL. XLIV. FIGS. 17 AND, 18.

Body highly retractile, oblong, flattened, rounded posteriorly, pointed
anteriorly, about twice as long as broad when extended, nearly orbicular
when contracted ; peristome-field extending backwards to a distance of
one-third of the length of the expanded body ; a transverse row of about
twelve slender anal styles projecting at the posterior extremity ; contractile
vesicle single, central ; parenchyma grey, more or less granular. Length
1-480" to 1-360". HAB. — Salt water.

Cohn omits, in his figures and description of this species, to record the character
* 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xx., 1870.

GENUS HIS TRIO. 789

of the ventral and marginal setae ; under these circumstances its retention among
the typical representatives of the genus Oxytricha must be regarded as provisional.

Supplementary Species.

Oxytricha tubicola, Gruber. PL XLIV. Fig. 12. — This species is briefly described
by Dr. August Gruber,* in company with Stichotricha socialis and several other
interesting marine and fresh-water species. Excepting, however, for its habit of
excreting and inhabiting a short tube, open at both ends, as shown in the accom-
panying figure, the data recorded are insufficient to define its true position with
relation to the other members of the Oxytrichidae. The character of this protective
element, if confirmed by future observation, at the same time suffices to indicate the
necessity that will probably arise of instituting a new generic title for its reception.

GENUS XXI. HISTRIO, Sterki.

Animalcules free-swimming, persistent in shape, ovate or elliptical,
bearing three large uncinate and a few smaller setose frontal styles, five
scattered ventral and five anal styles; an uninterrupted projecting fringe
of marginal but no caudal setae ; peristome-field with a reflected inner
border ; endoplasts two in number ; contractile vesicle situated near the
centre of the left lateral margin.

This genus is instituted by Sterki \ for the reception of the Stylonychia histrio of
Ehrenberg and more recent writers, which differs from the typical Stylonychia in
the entire absence of caudal setae.

Histrio Steinii, Mull. sp. PL. XLV. FIGS. 13 AND 14.

Body elongate-elliptical, somewhat lancet-shaped, slightly curved towards
the left ; the marginal setae continuous throughout ; no longer caudal setae
developed at the posterior extremity, and none of the anal styles project-
ing beyond the posterior border ; endoplasts ovate or nearly spherical.
Length 1-190" to 1-168". HAB.— Fresh water, among aquatic plants.

This animalcule is identical with the Kerona histrio of O. F. Muller, and the
Stylonychia histrio of Ehrenberg and Stein. The conversion of the old specific title
into a new generic one, and the adoption of a new name to replace the former as
accomplished by Sterki, is a course perhaps scarcely to be commended.

Histrio similis, Quenn. sp.

Body elongate-elliptical, straight, not quite three times as long as
broad, rounded at each extremity ; the marginal setae forming an even and
continuous lateral border ; no caudal setae ; anal styles five in number,
simple, straight, and slender, projecting for about half their length beyond
the posterior extremity. Length 1-225". HAB. — Salt water.

The straight and more regularly elliptical form of this species, in addition to the
prominence of the anal styles and salt-water habitat, distinguish this species from
Histrio Steinii, which it otherwise most nearly resembles.

* ' Zeit. Wiss. Zool.,' Bd. xxxiii., 1879. Also translation, 'Journal Royal Microscopical Society,'
vol. iii., No. 2, April 1880.

t 'Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxxi., 1878.

790 ORDER HYPOTRICHA.

GENUS XXII. ACTINOTRICHA, Cohn.

Animalcules free-swimming, slightly flexible, ovate or elliptical, the
anterior border of the ventral surface bearing five or six abnormally thick,
sharply-pointed frontal styles, a row of smaller styles produced down each
lateral margin, and a transverse row of five or six anal styles developed at
the posterior extremity ; adoral row of cilia very large, uncinate.

Actinotricha saltans, Cohn. PL. XLV. FIG. 6.

Body elliptical, equally rounded at both extremities, about twice as
long as broad ; the five large frontal styles radiating symmetrically from the
anterior border, the central style the largest, and the remaining ones gradually
diminishing in size backwards; eight or nine smaller styles entering into
the composition of each of the latero-ventral rows, the four posterior styles
in each row being about twice the length of the preceding four ; anal styles
long and stout, six in number, equal in size, forming an even transverse series,
often branched at their distal terminations ; peristome and adoral cilia
produced backwards to a distance of about one-third of the length of the
entire body ; parenchyma transparent, colourless. Length 1-360".

HAB. — Salt water, swimming evenly in a straight line, springing or
creeping.

It is difficult to decide whether the latero-ventral series of setae represented by
Cohn in his description and illustration of this species, belong rightly to the ventral
or to the marginal series; the author is inclined, however, to believe that they appertain
to the latter, and that the true ventral and probably also the frontal styles have been
overlooked. Should this inference prove correct, this single generic type, excepting
for the abnormal development of the six frontal styles, is closely allied to Stylonychia,

GENUS XXIII. STYLONYCHIA, Ehrenberg.

Animalcules free-swimming, persistent in shape, encuirassed, ovate or
elliptical ; peristome-field extensively developed, its reflected inner border
finely ciliate, usually bearing a band-like undulating membrane ; anterior or
frontal styles usually eight in number, occupying a more or less distinct
circular area ; five claw-like ventral styles or uncini, and five straight anal
styles ; the marginal setae forming on each side an even and continuous
border ; three long, hair-like caudal setae usually developed at the posterior
extremity ; endoplasts two in number, oval or elongate, sometimes cylin-
drical or bacillar, dividing into separate ovate nodules ; contractile vesicle
single, spherical, situated near the posterior angle of the peristome.
Inhabiting salt, fresh, and stagnant water.

Stylonychia mytilus, Ehr. PL. XLV. FIGS, i AND 18-22.

Body elongate-elliptical, more than twice as long as broad, rather wider
anteriorly, with a slight left curvature, tapering backwards from the centre,
the posterior third frequently becoming abruptly narrowed and bent
towards the left, the posterior termination mostly truncate ; peristome-

GENUS STYLONYCHIA. 791

field occupying the entire left side of the anterior ventral surface, its
reflected inner border ciliate and supporting a conspicuous, band-like,
undulating membrane ; the two right-side anal styles projecting beyond
the posterior extremity ; three long, widely separated, caudal setae springing
from the truncate posterior end, in which region the otherwise even and
prominently developed marginal series is considerably interrupted ; both
the anal and frontal styles occasionally fibrillate or branched at their
extremity. Length 1-280" to 1-72".

HAB. — Fresh water ; also abundant in infusions.

Sterki alludes briefly in his ' Morphologic der Oxytrichinen ' * to a variety of
this animalcule, upon which he confers the sub-specific name Stylonychia mytilus van
pusilla. The caudal setae in this modified type attain the length of one-half of the
body, and are either bi- or tri-furcate at their free extremities ; there are but from
twelve to eighteen marginal setae on the right, and from ten to fourteen only on the
left-hand lateral border, while the lengths of the larger examples range from 1-275"
to 1-200".

Stylonychia pustulata, Ehr. PL. XLV. FIGS. 15-17.

Body elongate-ovate, equally wide in front of and behind the median
line, the posterior extremity evenly rounded, bearing three long, closely
approximated caudal setae which scarcely interrupt the marginal series ;
three or four of the anal styles projecting beyond the posterior border ;
endoplasts oval. Length 1-280" to 1-120".

HAB. — Salt, fresh, and stagnant water.

This animalcule is common in infusions, and may be distinguished from the
preceding type, in addition to its smaller size, by its rounded posterior extremity, by
its more closely approximated caudal setae, and by the more numerously projecting
anal styles.

Stylonychia fissiseta, C. & L. PL. XLV. FIG. 22.

Form and dimensions of the body identical with those of S. pustulata ;
marginal setae fewer, larger, wider apart, and not projecting beyond the
peripheral border ; each of the five anal styles feather-like or fibrillate at
their distal extremity ; three very long, widely separated caudal setae,
branched in a trifid manner at their free end, projecting from the posterior
extremity.

HAB. — Fresh water : Berlin Zoological Gardens (C. & L.).

The illustration given by Claparede and Lachmann, here reproduced, represents
eleven anterior or frontal uncini, while their description testifies to only eight, the
normal number associated with this genus. The elegant branched or fimbriate
character of the anal styles in a manner resembling the feathering of an arrow, and
trifurcation of the caudal setae, as also the non-prominence of the marginal setae
serve to distinguish it readily from either of the preceding forms.

x Stylonychia macrostyla, Sterki.

Corresponding closely with S. mytilus, more or less flexible, rounded
anteriorly, the posterior margin broadest and truncate ; all the styles and

* ' Zeitschrift fur Wissenschaftliche Zoologie,' 1878.

792 ORDER HYPOTRICHA.

setae exceedingly long, the frontal series placed further back ; caudal setae
equalling half the body in length, flexible and trailing, not branched or
fimbriate at their extremities. Inhabiting fresh water.

Fam. VI. ETJPLOTID^E, Ehr.

Animalcules free-swimming, encuirassed, more or less ovate, with a
plane ventral and convex dorsal surface ; oral aperture ventral, situated at
the posterior extremity of an arcuate or subtriangular peristome-field, the
outer or left-hand border of the peristome bearing a linear series of stout
cirrose adoral cilia, shorter cilia of the same description sometimes con-
tinued up the reflected or right-hand border of the peristome ; anal styles
always present, those of the frontal and ventral series more or less con-
spicuously developed, also occasionally a few postero-marginal or caudal, but
never a continuous series of latero-marginal setae.

Excepting for the absence of latero-marginal setas, and the difficulty experienced
in discriminating between the groups of frontal and ventral styles, the members of
this family group correspond closely with those of the Oxytrichidae last described.
The peristomal system is also simpler, for while in some instances it possesses a
reflected inner border with an associated fringe of pre-oral cilia, no instance is as
yet known in which either an endoral or paroral series is represented. At the same
time, this little family group exhibits in certain points an advance upon that of the
Oxytrichidae, the cilia of the ventral aspect being more concentrated, and their
constituent elements being in all instances highly differentiated in the form of
styles and uncini. In the Oxytrichidae, on the other hand, the last-named appendages
may, as in Kerona and Trichogaster, take the form of minute setose cilia, and thus
lead the way through Peritromus and Litonotus to the more simply organized
Holotricha. By Stein the four genera here assembled under the title of the Euplo-
tidaa are divided into the two family groups of the Euplotina and Aspidiscina, the
second one being instituted for the reception only of the single genus Aspidisca.
As this type differs from the three other genera only in the more rearward location
of the peristome-field and consequent non-projection of the adoral fringe of cilia
beyond the anterior border, it has not been considered desirable to retain this dis-
tinction in the present volume. The indurated and more or less ovate or orbicular
carapace or cuirass of the members of this family group, combined with their truly
ambulatory mode of progress over the surface of submerged objects by aid of their
frontal and ventral styles, imparts to many of them an insect-like appearance. The
passage from the preceding family of the Oxytrichidae is possibly accomplished through
the genus Uronychia, in which two rudimentary, latero-marginal setae are found
developed on each side in close contiguity to the anal styles.

GENUS I. ASPIDISCA, Ehrenberg.

Animalcules free-swimming, encuirassed, orbicular or shield-shaped,
with a convex dorsal and plane ventral surface, the right-hand border of
the ventral surface having a thickened margin ; peristome-field set far back
on the left-hand side, associated with a simple arcuate fringe of adoral
cirri, which do not project beyond the anterior or left lateral margin ;
several large claw-like styles usually developed towards the anterior end and
in the centre of the ventral region, and from five to ten or twelve posterior
or anal styles ; anal aperture placed far back, debouching a little in advance
of the posterior or anal styles. Mostly inhabiting salt water.

GENUS ASPIDISCA. 793

Aspidisca lyncaster, Stein. PL. XLV. FIGS. 23 AND 24.

Body ovate, rounded on the right side and at the two ends, the anterior
border of the left side incised so as to produce a posteriorly directed
spur-like projection, a similar aculeate spur, curved slightly outwards, pro-
jecting from the ventral surface of the carapace on the same side, within a
short distance of the posterior margin ; ventral styles short and thick,
seven in number ; five anal styles ; endoplast band-like, curved ; contrac-
tile vesicle single, situated a little in advance of the anal styles. Length
of body 1-450" to 1-360". HAB. — Salt water.

Aspidisca lynceus, Ehr.

Body ovate, widest and somewhat truncate posteriorly; the marginal
border of the carapace entirely even, the left one straight, the right one some-
what convex ; the dorsal surface smooth, or marked longitudinally with three
feeble furrows ; the inferior surface bearing seven ventral and five anal styles.
Length of body 1-540". HAB. — Salt water.

Aspidisca turrita, C. & L. PL. XLV. FIGS. 31-33.

Carapace suborbicular, widest and somewhat truncate posteriorly, its
marginal border entirely even, the left side nearly straight, the opposite
one rounded, a thorn-like recurved spine developed from the centre of the
dorsal surface ; ventral styles as in A. lynceus. Length 1-450".

HAB. — Sea water.

Aspidisca polystyla, Stein.

Carapace oval, its margin entire, the left side border nearly straight ;
the dorsal surface slightly convex, traversed by three longitudinal grooves ;
ventral styles seven in number, forming two anterior, oblique, parallel rows
of three each, the seventh style stationed by itself to the right and rear of
the other six ; anal styles from ten to twelve in number. Length 1-510".

HAB. — Sea water.

This species, by reason of the greater number of the ventral styles, has formed
the type of Stein's sub-genus Onychaspis and, in connection with the last-named title,
has been elevated by Diesing * to the rank of an independent generic group.

Aspidisca hexeris, Quenn.

Carapace elliptical, about one and a half times as long as broad,
equally rounded at each extremity; the right-hand border armed, close
behind its centre, with a single, backwards directed, spur-like projection ;
ventral styles short and thick, seven in number ; six anal styles. Length
1-500". HAB. — Salt water.

Aspidisca sedigita, Querin.

Body broadly ovate, suborbicular, the right border smooth and rounded,
the left one incised so as to produce a central, anterior, and posterior spur-

* ' Revision der Prothelminthen,' 1866.

794

ORDER HYPOTR1CHA.

like projection ; ventral styles seven in number, short and thick, centrally
disposed ; six stout, scarcely prominent anal styles. Length 1-325".

HAB. — Salt water.

From Aspidisca lyncaster, which it would appear to most closely resemble, this
form may be distinguished by the presence of three instead of two lateral spur-like
projections on the left-hand border ; it is figured and described by Quennerstedt, in
company with the preceding type, in Part II. of his ' Sveriges Infusoriefauna,' 1867.

Aspidisca Andrewii, Mereschk.

Body elongate-ovate or subreniform, one and a half times as long as
broad, rounded at the two extremities, the posterior one being the wider, the
right-hand border evenly convex, the left one deeply indented at a distance
of one-third of its entire length from the anterior extremity ; the dorsal
surface of the carapace traversed by five parallel longitudinal grooves or
strise, a triangular or somewhat heart-shaped plate developed on the ventral
surface close to the posterior extremity, having its apex directed backwards
and reaching to but not projecting beyond the dorsal border of the carapace ;
ventral styles very large and short, seven in number, distributed in two
rows of four and three styles each ; anal setae long and fine, six in number,
four developed in a line to the right and two to the left of the ventral plate.
Length 1-480".

HAB. — Salt water : White Sea, abundant among algae (Mereschkowsky).

In its possession of six anal setse this species corresponds with the Aspidisca
sedigita of Quennerstedt.

Aspidisca costata, Duj. sp. PL. XLV. FIGS. 25-29.

Carapace nearly ovate, the ventral portion developed outwards and
backwards in the form of a triangular plate towards the posterior extremity
of the left side ; the dorsal surface traversed by six longitudinal furrows ;
ventral styles as in A . polystyla. Length 1-690". HAB. — Pond water.

This animalcule is identified by Stein with the Coccudina costata of Dujardin and
•Perty, and with the Aspidisca cicada of Claparede and Lachmann. The author
has on a recent occasion witnessed a highly interesting developmental phenomenon
in association with this cosmopolitan species that does not so far appear to have
been recorded by any other observer. In pond water abounding with this type
there were likewise observed large numbers of a minute, oval, depressed form
closely allied to the Glaucoma margaritaceum of Claparede and Lachmann, which
is identified by them with the Cyclidium margaritaceum of Ehrenberg and the
Cinetrochilum margaritaceum of Perty. The only point of distinction to be discovered
in the variety personally examined consisted in the fact that there were three long,
hair-like, posterior or caudal setae in place of the single one observed by Claparede
and Lachmann. As shown by these last-named authorities, the oral orifice is
situated towards the posterior extremity, and has projecting from its aperture a delicate
vibratile membrane, described by Stein in Glaucoma scintillans as consisting of two
separate tremulous flaps, and with which structure that of G. margaritaceum is stated
to coincide. Prolonging the examination of a single individual for a lengthened
interval, the author was greatly surprised to notice the gradual appearance, towards
the posterior end, of two thick style-like appendages, at first very weak and flexible,
followed by the development of others both here and towards the anterior extremity,
the animalcule shortly becoming transformed through these and the following modi-

GENUS GLAUCOMA. 795

fications into an Aspidisca, undistinguishable from the adult forms abundantly
present with it in the surrounding water. Simultaneously with the growth of the
ventral and anal styles, the fine vibratile ventral cilia and terminal hair-like setae
were gradually absorbed and obliterated, the vibrating oral membrane unrolled and
extended itself, became transversely stnate at regular intervals, and eventually split
up to form the characteristic adoral fringe of cilia. The whole of these metamorphoses
occupied a space of less than an hour, the animalcule at this early stage of its
adolescent career being, however, decidedly weak on its " legs," as its locomotive
styles may be appropriately designated, and staggering about after the manner
of a newly-born calf or colt. Both in its adult -and larval or Glaucoma stage
Aspidisca costata exhibits an eccentricity of gait, which may be cited as correlative
evidence in demonstration of their identity. This peculiarity alluded to is manifested
by the tendency of the animalcule in either case to rotate upon a fixed point as
though upon a pivot, or to persevere in the maintenance of a restricted circuitous
course within the area of the microscopic field ; the action in this latter instance
is highly suggestive of the gait exhibited by a playful child as it pushes itself
round and round in a circle, one leg only being permitted to exert a locomotive
function.

With reference to the foregoing observation, the author, in place of conceding
to the genus Glaucoma the rank of an independent generic type, is inclined to regard
its members as mere larval conditions of Aspidisca and other allied Hypotricha.
To which species the Glaucoma scintillans of Ehrenberg ultimately develops has yet
to be determined. In accordance, nevertheless, with Stein's more recent drawings
and description of this type, the oral aperture is situated near the anterior extremity,
and the contractile vesicle at the opposite end, and from these circumstances it may
be predicted as more likely representing the earlier stage of a Euplotes or
Uronychia, in both of which the oral orifice is more anteriorly located than in
Aspidisca. The bi-labiate structure of the oral membrane of Glaucoma, as described
by Stein and Claparede and Lachmann, is evidently a misinterpretation of the optical
aspect of a revolute single lamina. No trace of an endoplast could be detected by
the author in the Glaucoma condition of this species, and only in the older
examples of the adult Aspidisca. Increase by transverse fission was frequently
observed during this embryonic phase, such circumstance demonstrating that this
reproductive process is not confined to the adult stage, and is therefore not
diagnostic of it even among the higher Ciliata. The diagnosis of the genus
Glaucoma, with its two species herewith subjoined, as also that of the genus Micro-
thorax of Engelmann, are allotted, in this treatise, a provisional status only, being
regarded by the author as representing, in all probability, mere transitional or
embryonic phases of higher Hypotrichous forms.

GENUS II. GLAUCOMA, Ehrenberg.

Animalcules free-swimming, persistent in shape, more or less ovate, with
a convex and frequently grooved dorsal and a plane or flattened ventral
surface ; oral aperture ventral, associated with a minute, vibrating, flap-like
membrane ; fine vibratile cilia more or less completely clothing the ventral
surface, these occasionally supplemented by one or more hair-like caudal
setae.

Glaucoma scintillans, Ehr. PL. XLV. FIGS. 39 AND 40.

Body ovate, depressed, the margin entire and equally rounded at the
two extremities ; the oral aperture with its projecting vibratile membrane
developed towards the anterior extremity ; the contractile vesicle posteriorly
located ; cilia projecting all round the periphery as a marginal fringe, and

796 ORDER HYPOTRICHA.

covering the entire ventral surface of the body ; no caudal setae. Length
1-280". HAB. — Pond water and infusions.

The relatively large size of this animalcule suggests the probability of its being
the imperfect or larval form of a species of Euplotes.

Glaucoma margaritaceum, Ehr. sp. PL. XLV. FIG. 30.

Body oval, with an emargination or notch on the left-hand side of the
posterior border ; contractile vesicle situated posteriorly in close vicinity to
this notch, and the oral aperture with its tremulous membrane on the oppo-
site or right-hand side of the same region, but a little more forward ; the
dorsal surface obliquely or nearly longitudinally grooved or striate; a
single long hair-like seta projecting obliquely towards the left from the
posterior extremity. Length 1-150x3" to 1-720". HAB. — Pond water and
infusions.

This type is identical with the Cydidium margaritaceum of Ehrenberg and the
Cinetrochilum margaritaceum of Max Perty.

GENUS III. MICROTHORAX, Engelmann.

Animalcules of minute size, free-swimming, more or less oval, flattened,
persistent in shape ; the cuticular surface indurated ; the oral aperture
debouching upon a small fossa on the left-hand side of the hinder extremity
of the ventral surface, associated with a flap-like vibrating membrane ;
cilia confined to the ventral surface, most conspicuous at the two extre-
mities ; endoplast and contractile vesicle subcentral.

In general aspect, and in the character of the oral organ with its vibrating
membrane, the minute animalcules referred by Engelmann * to this genus so closely
resemble those of the genus Glaucoma here treated as developmental conditions only
of more highly organized Hypotrichous forms, that their present retention under a
separate generic heading must be regarded as provisional.

Microthorax sulcatus, Eng. PL. XLV. FIG. 37.

Body oval, depressed, rounded posteriorly, somewhat pointed anteriorly
and curved slightly towards the left, the . left border flattened or slightly
concave, the right one convex ; the dorsal surface traversed by three deep,
widely separated, longitudinal grooves ; oral aperture developed at the
posterior extremity, close to the left-hand border ; the cilia longest, and most
conspicuous at the two extremities, confined to the ventral surface ; con-
tractile vesicle situated a little in advance of the oral fossa ; endoplast
ovate, subcentral. Length 1-425". HAB. — Fresh water.

A second species, Microthorax pusillus, Eng., differs from M. sulcatus only in
its smaller size, 1-750", and in the absence of the dorsal furrows; it probably
represents a younger phase of the same animalcule. The resemblance of this
type to the Cinetrochilum margaritaceum of Perty (Glaucoma scintillans, Ehr.) has
been already remarked by Wrzesniowski.

* ' Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xi., 1862.

GENUS URONYCHIA. 797

GENUS IV. URONYCHIA, Stein.

Body oval, encuirassed, turgid, the sides rounded, truncate in front,
with a prominent membranous upper lip ; the hinder extremity having
developed on the ventral surface two converging bow-shaped fissures, into
which the short, claw-shaped, anal and marginal uncini or styles are
inserted ; ordinary ventral and frontal styles entirely absent ; the peristomal
excavation pocket-shaped, closing sphincter-wise at will, its inner or right-
hand border bearing a band-shaped undulating membrane.

The type and as yet single known species of this genus is the Trichoda transfuga
of Miiller and Plo&sconia scutum of Dujardin and Stein's earlier writings. The present
generic title was conferred upon it by Stein * in the year 1865.

Uronychia transfuga, Mull. sp. PL. XLV. FIGS. 34-36.

Body ovate, truncate in front, slightly narrower posteriorly, more usually
obliquely truncate, angular, and bent towards the left, but sometimes evenly
rounded, the lateral margins symmetrical ; peristome-fossa extending from
the anterior end to the centre of the body, widened posteriorly ; the surface
of the dorsal region sometimes smooth, sometimes longitudinally ribbed ;
anal uncini and styles variable in character and number, usually from three
to seven or eight recurved and occasionally fimbriate uncini inserted in the
right-hand posterior cleft, but not more than two on the opposite one ;
each of these fascicles occasionally supplemented by two fine simple setae.
Length of body 1-288". HAB. — Salt water.

This species appears to be subject to a wide range of both local and individual
variation with respect to the number and character of the stylate appendages
of the posterior extremity of the body. In some instances these appendages are
straight, or but slightly bent, in others strongly curved or uncinate, while in
a third series they are branched in an elegant feather-like manner. The posterior
termination of the carapace, and also the character of its dorsal surface, as shown
in the diagnosis, exhibits a similar tendency to vary. There can be but little
doubt, the above facts considered, that the Campylopus paradoxus of Claparede
and Lachmann | is, as anticipated by Stein, identical with this species, though these
last-named authorities seem to have failed in detecting the undulating membrane
on the right border of the peristome, and which without very careful e.% mination
is likely to escape notice. The author has obtained this singular animalcule from
Brighton and the Jersey coast, and also in sea-water from the Aston Aquarium,
Birmingham, remitted by Mr. Thos. Bolton.

GENUS V. EUPLOTES, Ehrenberg.

Animalcules free-swimming, encuirassed, shield-shaped, elliptical, or
orbicular, with sharp laminate marginal edges, and usually a plane ventral,
and convex, sometimes furrowed, dorsal surface ; peristome-field arcuate,
extending backwards from the frontal border to or beyond the centre of
the ventral surface, sometimes with a reflected and ciliate inner border ;
frontal styles or uncini six or seven in number ; three or more irregularly

* ' Bohmische Gesellschaft der Wiss.,' Bd. x.
t 'Etudes sur les Infusoires,' 1858.

798 ORDER HYPOTRICHA.

scattered ventral styles, and five anal styles ; four isolated and often
fimbriated caudal styles or setae developed along the posterior margin ;
endoplast linear, curved ; contractile vesicle single, spherical, situated imme-
diately beneath the origin of the right-hand anal styles. Inhabiting salt
and fresh water. Multiplying rapidly by transverse fission.

Euplotes patella, Ehr. PL. XLIV. FIGS. 23-25.

Carapace elliptical, anteriorly truncate, its upper lip or lamina triangular,
projecting above and considerably overlapping the anterior margin of the
peristome ; the inner and reflected border of the peristome represented by a
simple unciliated groove or channel; frontal styles six in number, three
scattered ventral styles, the two more posterior caudal styles branched or
fimbriated ; the dorsal surface usually traversed by seven longitudinal
furrows ; endoplast band-like ; contractile vesicle single, situated near the
anal aperture. Length 1-196". HAB. — Salt and fresh water.

This species, like many other Hypotricha, is subject to considerable local and
individual variation, chiefly evinced in this instance in the varying contour of the
carapace and in the character of its ornamentation. This carapace or cuirass,
while normally oval or elliptical, may be nearly circular or lozenge-shaped, broad
in the centre and much narrower at the antero-posterior extremities. The longi-
tudinal sulci again, which usually form a well-developed series extending from one
end to the other of the dorsal surface, are sometimes developed only in the posterior
region, or may be altogether absent. The number, character, and arrangement ot
the various stylate appendages appear always in this species to accord with that
normal formula given in the foregoing diagnosis.

So long since as the year 1869 * the author placed on record an observation con-
cerning an example of the species that up to within a recent date he has been
entirely unable to reconcile with the characteristic structure of either this special type
or any representative of the present order. In this instance long flagella-like cilia
were reported as projecting from the anterior extremity, of a length and character
altogether distinct from those usually entering into the composition of the
peristomal fringe of either Euplotes or its nearest allied generic types. Assisted,
however, by the light contributed by the developmental phenomena of Aspidisca
costata, recorded in a previous page, and in which it has been shown that the peri-
stomal fringe of cilia commences its existence as a simple vibratile membrane, the
phenomenon now referred to becomes more intelligible. In numerous instances the
permanent vibratile membranes of various Infusoria, such as obtain in the genera
Condylostoma, Blepharisma, Pleuronema, and others, have been first interpreted and
figured as flagella, their true significance being demonstrated only through more
recent and carefully conducted investigation ; and in like manner it may be con-
sistently predicated that the supposed flagella observed on the occasion quoted
represented the undulating outline of the primary vibratile membrane of the type in
question previous to its splitting up into the ciliary adoral wreath that characterizes
the adult form. Inferring at the time that this animalcule represented a fully
developed adult individual, we proposed to distinguish it by the title of Euplotes
paradoxa in reference to the apparent abnormal presence of long flagella. The
author is now satisfied, however, that the form represented an example of Euploles
patella, previous to the complete perfect development of its adoral ciliary wreath.

A variety of Euplotes patella having evenly parallel sides and a more elongate
elliptical contour, has recently received from Wrzesniowski the subspecific title
E. patella var. eurystomus.

* ' Monthly Microscopical Journal,' vol. i. pi. xii. fig. 5, p. 291.

GENUS EUPLQTES. 799

Euplotes harpa", Stein. PL. XLIV. FIG. 22.

Carapace elongate-oval, nearly twice as long as broad, the anterior
extremity widest, rounded, having a projecting tooth-like process at the
right-hand corner ; two similar but larger and blunter denticulations deve-
loped on the anterior margin of the ventral surface ; seven frontal and
nine scattered ventral styles ; five anal, and four isolated unbranched
postero-marginal setse ; the reflected or inner border of the peristome exten-
sively developed, finely ciliate ; eight straight longitudinal furrows travers-
ing the dorsal surface of the carapace. Length 1-168" to 1-144".

HAB. — Salt water.

This species, which is the largest representative of the genus, may be readily dis-
tinguished from the preceding type by the toothed "edge of the lower surface of the
carapace, the reflected and ciliate peristomal border, and by the simple unbranched
character of the posterior marginal styles.

Euplotes longipes, C. & L.

Carapace elliptical, its right and left borders nearly straight and parallel
to one another, the anterior and posterior margins equally rounded ; the
front edge of the lower surface of the carapace simply curved, not denticu-
late ; no ciliated reflection of the peristome-border; the dorsal surface
smooth ; seven frontal and three ventral styles, the postero-marginal ones
unbranched. Length i-i 80". HAB. — Saltwater.

Stein anticipates that this specimen may possibly be identical with his Euplotes
harpa. The author has, however, met with a form precisely agreeing with the
description given by Claparede, in sea-water at Bognor, Sussex, in September 1873.
The even elliptical contour and undenticulate anterior ventral margin, together with
the simpler character of the peristome of the examples examined, assisted at
once in distinguishing it from Stein's type.

Euplotes charon, Mull. sp. PL. XLIV. FIGS. 26-29.

Carapace shortly oval or suborbicular ; the anterior and posterior
extremities obliquely truncate, parallel to one another; the right side
feebly but the left side strongly convex ; the dorsal surface usually ribbed
longitudinally; the anterior margin of the lower surface of the carapace
entire, or slightly indented; the reflected peristome-border simply grooved,
unciliate; seven frontal and three ventral styles; the posterior marginal
setae small, unbranched. Length 1-320" to 1-260".

HAB. — Salt and fresh water.

The shorter and almost orbicular contour of the carapace of this species serves at
a glance to distinguish it from either of the preceding varieties, while from E. patella,
with which it is most likely to be confused, it substantially differs in the larger
number of the frontal styles and in the unbranchfd character of the postero-marginal
setas. Sharing the extensive or cosmopolitan distribution of the last-named type, it
is subject to considerable local variation, and more especially with reference to the
ornamentation of the dorsal surface of the carapace, and which, while usually more
or less extensively furrowed, is not unfrequently perfectly smooth. Examples derived
from salt water only have been observed to attain the larger of the two dimensions

800 ORDER HYPOTRICHA.

quoted in the foregoing diagnosis. Among the numerous synonyms with which this
abundantly distributed species has been connected by the earlier writers, the follow-
ing, as given in Stein's monograph of the Hypotricha, may be more especially
mentioned : Trichoda charon and cimex of Miiller ; Euplotes charon and appendiculatus
of Ehrenberg ; and Plxsconia charon, affinis, subrotunda, radiosa, and longiremis of
Dujardin.

GENUS VI. STYLOPLOTES, Stein.

Animalcules free-swimming, encuirassed, elliptical, turgid, the carapace
rounded and thickened at the lateral margins, with a projecting antero-
dorsal lip ; the hinder extremity obliquely truncate ; a band-shaped median
channel or excavation extending from one end to the other of the ventral
surface, in which are situated the arcuate peristome-field and also the stout
frontal, ventral, and anal styles or uncini. In addition to these last-named
elements, a supplementary postero-marginal fascicle of caudal styles is
usually developed.

Styloplotes appendiculatus, Ehr. sp. PL. XLIV. FIGS. 30 AND 31.

Body elliptical, the anterior end ovoid, somewhat pointed, the posterior
extremity obliquely truncate, curved to the right; five frontal and four
ventral styles, two of the latter situated in the centre of the median groove,
and two near the left lateral border ; anal styles very long, five in number,
variously curved, closely approximated, and forming a single transverse row,
which projects considerably beyond the posterior margin ; a supplemen-
tary postero-terminal or caudal series, composed of three recurved uncini,
developed upon the posterior border. Length of body 1-380" to 1-260".

HAB.— Salt water.

Stein identifies this species with the Stylonychia appendiculata of Ehrenberg,
the Ploesconia scutum (in pars) and Diophrys marina of Dujardin, and with the
Euplotes excavates and Schizopus norvegicus of Claparede and Lachmann.

The author has recently obtained it in abundance in the neighbourhood of
St. Heliers, Jersey, and had then under examination an apparent embryonic form.
The complete life-history was not fully traced, but it was observed that in an early
stage of development it differs remarkably from the adult animalcules, possessing
no frontal, ventral, or anal styles, but simply an anterior or adoral fringe of cilia.
Under these conditions its movements are almost exclusively natatory, its translation
through the water being very swift, and its general aspect somewhat approaching
that of a Strombidium.

The type referred to the family Euplotina by Ehrenberg, under the title of
Himantophorus charon, is regarded by Stein as not improbably identical with
Onychodromus grandis. The Discocephalus rotatorius of the same author is
apparently an imperfectly observed representative of the genus Aspidisca.

CHAPTER IX.

SYSTEMATIC DESCRIPTION OF THE INFUSORIA-TENTACULIFERA.

Class III. TENTACULIFERA, Huxley.

Animalcules bearing neither flagellate appendages nor cilia in their adult
state, but seizing their food and effecting locomotion, when unattached,
through the medium of tentacle-like processes developed from the cuticular
surface or internal parenchyma ; these tentacles simply adhesive, or tubular
and provided at their distal extremity with a cup-like sucking-disc ; an
endoplast and one or more contractile vesicles usually conspicuously
developed ; trichocysts rarely, if ever, present ; increasing by longitudinal or
transverse fission or by external or internal bud-formation. Inhabiting salt
and fresh water.

The Tentaculiferous Section of the Infusoria, comprising Acineta and its allies,
while including, in comparison with the classes of the Flagellata and Ciliata already
described, a relatively small number of generic and specific forms, invites, with
reference to the remarkable structural and developmental features of its members,
an equal or even greater share of the biologist's attention. Although, as previously
shown,* the Tentaculifera, during their normal adult phase of existence, betray no sign
of affinities with either of these preceding classes, they are in their embryonic
condition more or less completely clothed with vibratile cilia, and may also, under
certain conditions (see Podophrya fixa) temporarily develop cilia in place of their
tentacula. It may be hence logically predicated that this class of the Infusoria is an
offshoot from the Ciliata, and that it consequently occupies a relatively higher position
in the zoological scale than do the members of the last-named class. Supplementary
evidence is afforded in this direction in connection with the fact that the ciliation of
the embryos of the Tentaculifera conforms roughly among the various species and
genera with that of the three more important groups of the Ciliata distinguished by
the titles of the Holotricha, Peritricha, and Hypotricha ; the cilia in like manner
being in one series developed upon the entire cuticular surface, in a second being
restricted to an anterior tuft or annular girdle, while in a third the cilia are developed
exclusively on the ventral surface of the body. It is further worthy of remark that
the holotrichously ciliated embryos are derived from the simplest Tentaculifera,
such as Podophrya, while the hypotrichous embryos are the more exclusive produce
of such higher types as Dendrocometes and Ophryodendron.

The recognition of the Tentaculifera as a distinct class or order of the Infusoria
has been accomplished at a comparatively recent date. By Ehrenberg, as shown in
his Classificatory System, Vol. I. p. 201, they were referred together with the Diatoms
and Desmids to the group of the Bacillaria, while Perty included them with
Actinophrys in his group of the Actinophrina. Stein for many years advocated the
opinion that its members represented developmental phases only of various

* See Vol. I. p. 107 et seq.
VOL. II.

802 CLASS III. TENTACULIFERA.

Vorticellidae, such inference being arrived at in connection with the circumstances
that many Acineta, e. g. Podophrya quadripartita, Podophrya carchesii, and P. phry-
ganidarum are found usually closely associated with certain compound Vorticellidas,
while in their ciliated embryonic state their resemblance to free Vorticella is very
remarkable. In accordance, indeed, with Stein's theory, every one of the earlier
known Acinete forms represented but the immature or embryonic condition of
a Vorticellidan type, the respective species to which they were in his opinion
related being indicated in the following specific descriptions.* It was the researches
more especially of Messrs. Claparede and Lachmann, having as their end in view
the solution of the vexed question of their affinities, that conduced chiefly to the
elucidation of the true nature of this remarkable group of organisms, and which won
for them that independent position which has since bee n universally accorded. As a
distinct section of the Infusoria, possessing the same status as that of the Ciliata
and the Flagellata previously described, and with reference more particularly to their
manner of ingesting food, and the character of their tentacle-like appendages,
Claparede and Lachmann conferred upon these Infusoria the title of the Suctoria.
More recent investigations having, however, elicited the existence of forms allied
to Acineta in which a portion only of the tentacles are suctorial, or which again may
be entirely non-suctorial and simply prehensile, Professor Huxley \ has proposed
to substitute for the Suctoria the more appropriate title of the Tentaculifera, which
is here utilized, Claparede and Lachmann's name, with the new one of the Actinaria,
being at the same time retained for the distinction of respectively the suctorial and
non-suctorial series.

The histological composition of the Tentaculifera corresponds substantially with
that of the two classes hitherto described ; an external cuticular layer, internal
granular protoplasm, and the essential structures, an endoplast or nucleus and one
or more contractile vesicles, are usually recognizable. The endoplast, it may be
remarked, is in many forms, e. g. Hemiophrya gemmipara, and Podophrya Steinii,
extensively ramified, though in no instance as yet known is there a multiplicity of
endoplastic structures as obtain among many of the Ciliata. The majority of species
are sedentary in their habits, thus offering an additional point of resemblance to the
Vorticellidae, with which they were originally correlated. In like manner, while some
are sessile, others are stalked, and may be either naked or enclosed within a trans-
parent sheath or lorica. Although up to the present time no Tentaculiferous type
has been discovered in which the individual zooids are united by their pedicles, and
thus form, precisely as in Carchesium or Epistylis, a compound zoodendrium, an
almost equivalent colonial modification obtains in the genus Dendrosoma. Here,
however, the separate zooids, as represented by each tentaculiferous ramuscule, are
indissolubly united, possess in addition a common creeping stolon, and more
nearly approach the constitution of a multicellular animal or metazoon than can
perhaps be predicated of any of the forms previously noticed. A less decisive
advance in the same direction is apparently accomplished in the form hereafter
described under the title of Ophryodendron multicapitata, while potential multi-
cellularity, as with the multinucleate Ciliata, would also appear to obtain in all those
types distinguished by the ramifying character of their endoplast. Although among
the majority of loricate species, the protective sheath or lorica differs in no essential
respect from those formed by the Ciliate or Flagellate groups of the Infusoria, in
certain other forms it presents a more complex character.

Thus in Acineta vortictlloides and A. divisa it has been shown by M. Fraipont J
that the fundus of the lorica is separated from the anterior region by a distinct
membranous septum or platform, upon which the animalcule's body rests, while in
Acineta tuberosa the membranous wall of the lorica covers in also the anterior

* Following Stein's lead, a similar subordinate position is accorded to the Acinetidoe in
Prichard's 'Infusoria,' latest edition, 1861.

t ' Anatomy of the Invertebrata, ' 1877.

j " Recherches sur les Acinetiens de la Cote d'Ostende," ' Bull, de 1'Acad. de Bruxelles,' 1877
and 1878.

CLASS III. TENTACULIFERA. 803

border of the periphery, leaving two small orifices open only for the passage of
the tentaculate appendages. In Atineta mystacina a series of triangular plates or
valves, having slit-like interspaces for the exit of the tentacles, protect in a like
manner the more ordinarily exposed anterior margin of the body. Some difference
of opinion exists respecting the significance and point of origin of the tentacles
of the Acinetidae. By some authorities, including Hertwig and Koch, it has
been represented that these organs are independent of and perforate the external
cuticular membrane, being produced from the central endoplasmic region of the
body. Stein, Zenker, and Fraipont, on the other hand, maintain that the tentacles
consist essentially of tubular prolongations of the external cuticle only. Still
more recently, M. E. Maupas, in his important memoir devoted to the con-
sideration of this group,* has arrived at the conclusion that, while in the majority
of cases these appendages are direct prolongations of the cuticular region, in certain
instances, including more particularly the members of the genus Hemiophrya,
the suctorial tentacles originate, as interpreted by Hertwig, from the deeper
endoplasmic layer. So far, notwithstanding the number of species carefully
examined, the author has been unable to connect the origin of the external or main-
wall of the tentacles of either description belonging to this class with any other than
the cuticular element, though in all instances their axial substance or central cavity, as
the case may be, is in direct communication with the endoplasm or internal body-
substance.

While the extension of the tentacles would appear to be accomplished by the
injection into them of the fluid protoplasm of the body, their retraction is visibly
brought about, in many species, and most probably in all, through the medium of an
exceedingly delicate membranous fibrilla which is developed spirally throughout the
length of the tentacles, in some species apparently on the inner, and in others on
the external surface. When the tentacle is fully extended, the fibrilla is usually so
straightened and attenuate as to be imperceptible, while conversely, on being retracted,
it is thrown into more or less closely approximated transverse folds. Podophrya
elongata, as recently examined by the author, has been found to illustrate this type of
differentiation in a marked degree, while an apparent homologue of this contractile
element is' developed in a yet more conspicuous manner in the proboscidiform organ
of Ophryodendron. As intimated by Fraipont, the fluid contents of the tentacles,
discharged by their contraction or derived by suction from captured prey, on arriving
at and being emptied into the soft protoplasmic substance of the body, continue,
as the necessary resultant of the forces set in motion, in a straight line with the
axis of the tentacle, producing the optical appearance in many instances that
these appendages, as interpreted by Hertwig, really originate at some distance
within the central protoplasm. In Acineta tuberosa an identical aspect is
brought about by the fact that the two lateral bundles of tentacula are, when
contracted, invaginated to a considerable distance beneath the surface of the
cuticle.

The phenomena of food-ingestion as manifested by the typical Tentaculifera or
Acinetidse are highly remarkable. Their food, which consists mainly of other ciliate
Infusoria, is seized by the adherent infundibulate or capitate extremities of the
extended tentacles, a perforation in the cuticle of the captured prey at the point of
contact is almost immediately effected, and the fluid or semi-fluid contents of the
victim's body are transferred by suction in a continuous stream through the tubular
tentacle into the body of the Acinetan. While this inges,tive process is recognisable
in most instances, and while in many cases the tubular character of the tentacles is
so well defined that the two walls of the tube are clearly shown in optic section
when viewed with sufficient magnification, in some species, such as Spharophrya
magna, the axis of the tentacle, according to Maupas, consists of clear homogeneous
sarcode continuous with that of the body, and the incorporation of the protoplasmic

* " Contribution a 1'Etude des Acinetiens," ' Archives de Zoologie Experimentale,' torn, ix-
No. 3, November 1881.

Z 2

804 CLASS III. TENTACULIFERA.

material of its captured prey is brought about on an entirely distinct principle.
The interpretation arrived at by Maupas in this connection is indeed of such
importance that a quotation in extenso from his description of this process may
be appropriately introduced. Referring especially to the above species named, he
states : —

" When an Infusorium is securely caught by an Acinetan and held at the extremity
of one of its tentacles, a rupture is produced in the cuticle of the victim at this
point of contact. The axillary substance of the tentacle penetrating this perforation
then passes into the body of the Infusorium, and probably accelerates its death.
The tentacle now increases greatly in thickness, this thickening being without doubt
due to the afflux of sarcode from the body of the Acinetan, and of which indeed the
axillary substance of the tentacle is but a continuation. A current is thus established
from the Acinetan in the direction of its prey, which is, however, not visible in con-
sequence of the transparency and freedom from granulation of the sarcode stream.
On penetrating the body of its victim this sarcode mixes freely with that of the
captured prey, and loading itself with all assimilable substances, returns to its point of
departure and thus produces the inflowing current that is so distinctly seen by
reason of the opaque granular particles held in suspension." M. Maupas proceeds
to explain that this phenomenon is directly comparable with the sarcode circulation
observable in the extended pseudopodia of the Foraminifera, or .with the intracellular
rotation or cyclosis in certain vegetable cells. The chief difficulty in the way of
such interpretation consists, he admits, in the fact that in the tentacle of the
Sphizrophrya an incurrent stream is alone visible, while in the pseudopodium of a
Foraminifer one in each direction is distinctly developed. Such apparent incon-
sistence. is, however, explained by the fact above mentioned that the excurrent
stream-/ while doubtless existing, is invisible through the absence of granular
particles, or, as likewise intimated by the same investigator, the two streams are
probably not coexistent, the returning or food-laden centripetal stream setting in
independently subsequent to the suspension of the invisible outflowing or centrifugal
one. This continuous centripetal current exhibited by the Acinetan during the
act of ingestion, is finally, by the above interpretation, likened to the simple
inflowing stream generated by a Foraminifer when withdrawing the entire mass of
its greatly extended pseudopodium into the substance of its body. The effort made
by Maupas to reconcile the anomaly in structure and function that seemingly
subsists between the suctorial tentacles as represented by such distinct types as
Hemiophrya gemmipara and Sphtzrophrya magnet — these in the first-named form
being distinctly tubular, and, as so far reported, literally suctorial, and in the second
case solid and bringing about the ingestion of food-matter through the circulatory
movements of its central core — appears to be scarcely needed. The author is of
opinion, indeed, that the interpretation arrived at by this investigator in connection
with Spharopkrya magna is also applicable to Hemiophrya and its allies, the
functional and structural properties and characters not differing absolutely in kind,
but only in degree. It may thus in the first instance be submitted that the
more solid contents of Hemiophrya, with its central canal, is as fully en rapport with
the endoplasmic substance of the body as that of the Sphtzrophrya, the difference
alone being that whereas this sarcode matter in the last-named type is retained
permanently within the soft-walled tentacle as a rod-like central core, in the other
iform, except when the animalcule is feeding, it is entirely withdrawn into the
substance of the body, leaving the relatively indurated walls of the tentacle standing
apart with a distinct central canal or lumen. The phenomena attending the
ingestive process would under the circumstances premised be precisely identical, with
the slight difference that while in the Spharophrya the sarcode is continuous from
the body to the orifice of the soft-walled tube, and available for the immediate
invasion and assimilation of the protoplasmic contents of the captured prey, in the
Hemiophrya it, under ordinary conditions, remains inert at the base of the tentacle,
and has to be projected through its axial cavity before placing itself in communica-
tion with its food.

CLASS ///. TENTACULIFERA. 805

Under any circumstances the new interpretation of the ingestive phenomena of
the Acinetidce, as represented in Spharophrya magna, arrived at by Maupas, is of
the highest import, inasmuch as it indicates, in a yet more decisive manner, the
probable affinity subsisting between this remarkable group and the Rhizopodal and
Radiolarian Protozoa. As pointed out by him, indeed, the tentacles of certain members
of the last-named group, such as Actinospharium, are constructed on a precisely
identical form as those of the Acinetan, consisting in like manner of a central shaft
or axis of clear transparent sarcode communicating with the central substance of the
body, and a more granular cortical layer which is continuous with the peripheral or
ectoplasmic layers. Maupas finally cites, in support of the probable Rhizopodal
affinities of the Acinetidae, an instance of a Rhizopod most nearly agreeing with the
Lieberkuhnia of Claparede and Lachmann, found by him in company with a minute
species of Arcella, and upon which it preyed in a manner coinciding remarkably with
that described of Sphczrophrya magna in connection with captured ciliate Infusoria.
The extremity of an extended pseudopodium was first thrust into the aperture of the
test of the Arcella and a double current set up in its substance, which was not
suspended until the entire protoplasmic substance of the Arcella was transferred to
its own body-mass in a manner identical with that recorded of Sphcerophrya Magna
and Cydidium glaucoma.

The possibility of a more or less remote relationship subsisting between the
Tentaculifera and the Hydroid polypes is tentatively discussed at page 104 of the
preceding volume ; further thought concentrated in this direction has suggested one
or two additional points of correlation. More especially the author has been struck
with the similarity of contour, and to no small extent of structure, that subsists
between the zooids of the remarkable Tentaculiferous genera Ophrwdendron,
Adnetopsis, and Urnula, and the so-called " nematophores " of certain Hydroitlea, such
as Plumularia setacea, Aglaophenia phima, and Ophiodes mirabilis, as figured and
described by Mr. Hincks in his ' British Hydroid Zoophytes.' Adnetopsis rara and
Urnula epistylidis, possessing membranous sheaths or loricae, are more especially
suited for comparison in this connection. These nematophores which, in a similar
manner as the " Dactylozooids " of the genus Millepora, would appear to represent a
degraded or imperfectly developed form of the normal alimentary zooids, take the
shape of granular protoplasmic masses enclosed in a cup-shaped cell, and capable of
protruding tentaculiform pseudopodic processes nearly resembling the proboscis of
Adnetopsis or Ophiodendron, in various directions. It is a remarkable coincidence
again that both of these infusorial genera occur as parasites, or rather commensals,
of Sertularian zoophytes distinguished for the production of these homoplastic
nematophores. A point of relatively minor importance in this connection, but
possessing at the same time some slight interest, attaches itself to the fact that,
while in no present known Ciliate or Flagellate type is the anterior border of the
lorica protected by a series of converging triangular plates or valves forming an
operculum such as obtains in Adneta mystadna, a like structural modification is
common to the protective loricae or " hydrothecas " of a large number of Hydroid
zoophytes such as Campanulina repens and Cuspiddla costata, Hincks.

The author has found that the representatives of this group are specially suited
for permanent preservation, the tentacles remaining extended and retaining all the
characters of the living zooids on treatment with osmic acid. The addition of a
drop of picrocarmine assists materially in developing the form and position of the
endoplast where this structure is not distinctly visible.

In accordance with the system adopted in this volume, the Tentaculifera may
be divided into two natural subsections or orders as below : —

Tentacles wholly or partially suctorial ORDER I. SUCTORIA.

Tentacles entirely non-suctorial, merely adhesive .. ORDER II. ACT1NARIA.

And further into groups having family and generic significance in accordance with
the accompanying schedule.

[GENERA OF TENTACULIFERA-SUCTORIA.

8o6

ORDER TENT A CULIFERA -S UCTORIA .

A.

Simple.

GENER.

/ Fam. I. •
RHYNCHETID^E.
Animalcules with one
or two tentacles only. ,

Fam. II.

ACINETID-ffi.

Animalcules multi- i
tentaculate, tentacles
simple.

\ OF TENTACULI1
Freely motile, naked
Sedentary loricate .

^ERA-SUCTORIA.

(Tentacles
similar.
Tentacles
( Tentacles

Loricate, j Tentacles
{ similar.

j Free- j
Motile. < swimming./
( Repent . .
Affixed to a rigidl
pedicle /
dissimilar

3. Spharophrya.
4. Trichophrya.
5. Podophrya.
6 Hemiophrya.

r Lorica sessile ..
I Lorica pedicellate . .

8. Solenophrya.
9. Acineta.

B.

Com-
pound.

Fam. III.

j^DRO. Animalcules sessile, with an indurated cuticle. 10.
Multitentaculate,

tentacles branched. J

Dendrocometcs.

Fam. IV.

DENDROSOMID^E.

Animalcules multi-

tentaculate, forming

branching colonies.

Colonies naked, sessile \\.Dendrosoma.

GENERA
Fam. I. i

EPHELOTIDiE.

•*QTentacles simple,
ray-like.

Fam. II.
OPHRYODENDRID^E.
Tentacles repre-
sented by one or
more retractile pro-
boscidiform organs, i

„ OF TENTACULIFERA-ACTINARIA.
Animalcules naked, pedicellate

I. Ephelota.

Proboscidiform organ simple

3. Acinetopsis.
4. Ophrydendron.

Proboscidiform organ with terminal cirri . .

Order I. TENTACULIFERA-SUCTORIA.

A greater or less proportion of the tentaculate appendages suctorial in
character, usually capitate, and adhesive only at their distal extremities.

GENUS I. RHYNCHETA, Zenker.

Animalcules motile or temporarily attached, stalkless, consisting of a
more or less ovate body, bearing at the anterior extremity a single long,
essentially suctorial tentacle. HAB. — Epizoic.

Rhyncheta cyclopum, Zenker. PL. XLVI. FIGS, i AND 2.

Body freely motile, contractile, usually when extended elongate-conical,
three or four times as long as broad, widest and more or less truncate
posteriorly, attenuate and pointed anteriorly, and continued into a long,
slender, flexible and retractile tentacle-like sucker, which may be extended
to two or three times the length of the body ; endoplast broadly ovate,
central ; contractile vesicle situated between the endoplast and the anterior
extremity. Length of extended body 1-165".

GENUS URNULA. 807

HAB. — Fresh water, attached by the posterior extremity to the thoracic
limbs of Cyclops coronata.

The contour of this singular animalcule, with its conical body and attenuate
tentaculate appendage, is, as remarked by Zenker, not unlike that of a Euglena,
or, perhaps, may be described as approaching still more closely that of Astasia
trichophora ; the tubular and suctorial character of the terminal appendage demon-
strates at once, however, its relationship with the ordinary Acinetcs. In this
connection it more especially accords with that developmental condition of Acineta
ferrum-equinum, described and figured by the same authority, in which a single
terminal suctorial tentacle only has made its appearance. The present species is of
comparatively rare occurrence, from twelve to twenty examples of the Cyclops in
question yielding, on examination, but one specimen of Rhyncheta. Treated with
reagents the parenchyma of this type contracts and separates from the investing
cuticle, which then presents the aspect of a delicate transparent lorica.

GENUS II. URNULA, C. & L.

Animalcules bearing a single retractile, simple or sparsely branched,
filiform tentaculate appendage ; excreting and inhabiting a sessilely attached,
membranous lorica. Multiplying by the production of free-swimming
ciliated embryos, and by the subdivision of the entire body-mass into
sporular elements.

h

Urnula epistylidis, C. & L. PL. XLVIII. FIGS. 1-4.

Lorica transparent, gibbously ovate or urceolate, about twice as long as
broad, attached by a short obliquely developed attenuation of its posterior
region ; body nearly filling or occupying one moiety only of the cavity
of the lorica ; tentaculate appendage laterally developed, single filiform,
extensile for a distance surpassing twice the length of the body, usually
with one or two lateral branchlets, its substance distinctly granular ; con-
tractile vesicle single, subcentral ; endoplast unobserved. Length of
lorica 1-200".

HAB. — Fresh water, attached to the branching pedicle or zoodendrium
of Epistylis plicatilis.

As originally figured and described by Claparede and Lachmann,* Urnula
epistylidis was referred to the group of the Rhizopoda, they being led by their
observations to regard the filiform tentaculate appendage of this organism as the
homologue of the pseudopod of a typical Rhizopod rather than as the tubular
suctorial organ of an Acinetan. That the position here assigned to it is the correct
one is, however, sufficiently proved by the more recent investigations of Stein,
Engelmann, and Wrzesniowski. The multiplication of this species through both
the production of ciliated embryos and by the resolution of the entire body into
spore-like elements is recorded by Claparede and Lachmann. The ciliated
embryos, produced singly from the parent body, are finely striate in an oblique
direction, and apparently completely or holotrichously ciliate. The existence of
these embryos constitutes of itself substantial evidence in support of the Acinetan
affinities of Urnula, no known Rhizopodal type developing cilia at any period of its
existence.

* ' Etudes sur les Infusoires,' 1855.

808 ORDER TENTACULIFERA-SUCTORIA.

GENUS III. SPH^ROPHRYA, C. & L.

Animalcules illoricate, usually more or less spherical in form, with
distinctly capitate suckers scattered irregularly throughout the periphery ;
freely movable, and never developing a fixed pedicle as in the genera
Podophrya and Acineta. Occurring frequently as endoparasites within
other animalcules.

The unattached and earlier developmental phases of Podophrya and other
Acinete types are liable to be mistaken for representatives of this genus, and it is
only through definitely ascertaining their persistence of form and reproduction of
zooids similar to themselves that a place under this title may be accurately assigned
them. To the genus Spharophrya must be referred the majority of the tentaculate
animalcules formerly pronounced by Stein to be the Acinetiform embryos of
Stylonychia, Urostyla, Stentor, Paramatium, and other Ciliata, but since demonstrated
to be merely parasites or consociates of these types, and which have doubtless gained
access to the bodies of their respective hosts, in the germinal condition, in connection
with their ciliary currents or ordinary food-ingestion. It would seem highly
probable that the minute peritrichously ciliate animalcules that have in a like
manner been described by Stein and other authorities as similarly infesting various
Vorticellidae, represent embryonic states of either Sph&rophrya or allied Adnetidtz.
The contour and plan of ciliation of these organisms, it may be mentioned, corre-
sponds more especially with that of the germs of the genus Podophrya. The so-
called embryos of Epistylis plicatilis, as observed and figured by Claparede and
Lachmann, reproduced at PI. XXXIX. Figs. 13-15, are not improbably referable to
the same category. Engelmann * has recently proposed to confer upon these Vorti-
cellidan parasites the distinct generic title of Endosphara^ and to relegate them to
a position among the Infusoria Ciliata. Lacking evidence, however, to show that
these organisms propagate independently, it is not considered desirable by the author
to separate them from the group with which phylogenetically they would appear to
possess the closest affinities.

Sphserophrya pusilla, C. & L. PL. XLVI. FIG. 6.

Body minute, spherical, bearing a variable number of short widely
scattered suckers ; contractile vesicle single j endoplast ovate. Diameter
1-650". HAB. — Fresh water.

Claparede and Lachmann attest to having encountered myriads of this animalcule
at Geneva in water containing Oxytrichce, and to which larger ciliate types they were
usually found singly attached. Other examples, floating freely in the water, were
observed to fix themselves in a similar manner to those Oxytrichcz t that chanced to
pass within reach of their short adhesive suckers, and almost invariably to select for
their point of attachment the left side of the ciliated oral groove of their host. From
this coin d'avantage these minute animalcules no doubt enjoy unprecedented
opportunities of intercepting on their own account an abundant supply of food-
material otherwise destined for the digestive cavity of their more agile and powerful
companions.

Sphserophrya magna, Maupas. PL. XLVIII. FIGS. 6 AND 7.

Body evenly spherical ; tentacles distinctly capitate, moderately
numerous, not exceeding fifty in number, rarely as many, their length,

* " Entwickelung von Infusorien, " ' Morphologisches Jahrbuch,' Bd. i., 1876.
t The figure given by Claparede most closely resembles Urostyla Weissei, St.

GENUS SPH&ROPHR YA. 809

when extended, equal to that of the diameter of the body, produced from
all parts of the periphery ; contractile vesicles one or two in number ; endo-
plast spherical, finely granulate, excentric : parenchyma usually granular
and opaque. Diameter of body 1-600". HAB. — Fresh water, Algeria.

The discoverer of this species, M. Maupas, in figuring and describing it,*
has placed on record some interesting data in connection with the structure of
the tentacles and the phenomena of food-ingestion. On many occasions it was
observed by him that the suctorial appendages exhibited during their extended
state a greater or less number of oval or spherical dilatations or varicosities, these
varicosities from time to time altering in shape or totally disappearing. Submitted
to high magnification it was shown that these dilatations were composed only of the
external or cortical element of the tentacles, the internal or axial part passing
straight through them, and remaining undisturbed by the alteration of contour that
they undergo. Maupas has been thus led to the conclusion that in this Spharophrya
tnagna and certain other Acinitidae the tentacles consist of a central axial filament
of amorphous sarcode upon which is superimposed an external layer of the same
element of much more delicate consistence, and possessing marked polymorphic
properties. He further anticipates that the button-like inflation of the extremity of
the tentacles in this and kindred species consists of an excurrent spheroidal mass of
the axial sarcode only, such interpretation being supported by his observation that
on a ciliated infusorian coming into contact with its substance, but succeeding in
escaping, this normally spheroidal mass presented under high magnification, as shown
at PI. XLVIII. Fig. ;£, a lacerated or ragged contour. By introducing into the
same water an abundant supply of the ciliate type Colpoda parvifrons and Cydidium
glaucoma, the Sphserophryae fed upon them voraciously, one example having been
observed by Maupas to seize and devour simultaneously no less than half-a-dozen of
these Holotrichous animalcules. The phenomena of ingestion, as described by this
investigator, are referred to at length in the section devoted to the general descrip-
tion of the Tentaculiferous class. In common with other species of the genus,
Spharophrya magna was observed to multiply abundantly by transverse fission, the
body becoming first elongated, then centrally constricted, and finally separating into
two subequal moieties. While one of these products soon assumed the spheroidal
contour and normal aspect of an adult zooid, the other one, withdrawing its tentacles,
became yet more elongated, its surface grew rugose, and ultimately developing fine
cilia at its anterior extremity, it swam away, the data observed being thus closely
analogous to those previously reported by the same authority of Podophyra libera.

Sphserophrya urostylae, Maupas. PL. XLVI. FIGS. 3-5.

Body subspherical ; suckers slender, their length about equal to the
diameter of the body, scattered irregularly over the surface of the periphery ;
one or two contractile vesicles ; endoplast spherical. Diameter of body
1-500." Embryos elongate-ovate, from three to four times as long as
broad, densely clothed with cilia, which exceed in length the scattered
suckers. HAB. — Fresh water, associated with Urostyla grandis.

The above title, originally adopted by the author in manuscript, has been
recently bestowed by Maupas on the species figured and described by Stein as the
Acin eta-phase of Urostyla grandis, and with which last-named type, according to the
representations of that authority, it is found associated in vast numbers ; whether,
however, these minute globular Adneta occupy the digestive cavity of their host
of their own accord, or are engulfed within the same by the ciliary currents of the

* " Contribution a 1'Etude des Acinetans," 'Arch, de Zoologie Experimentale,' torn, ix.,
Nov. 3, 1881.

8 10 ORDER TENTACULIFERA-SUCTORIA.

Urostyla, it is difficult to determine. The position taken up by Spharophrya pusilla
with reference to an allied ciliate type, namely externally, but close to the oral
aperture, favours the supposition that in other instances, like the present, they may
prefer to cultivate a still more intimate acquaintance with the commissariat of their
foster-parent. It is at all events certain that they are not incepted as food-material
or destined to be digested, as after being so enclosed, they are able to bore their
way out again through the parenchyma of their host, in either their adult condition
or in the form of ciliated embryos.

Sphserophrya stylonychlse, S. K.

Body subspherical, suckers short and slender, few in number, thinly
scattered throughout the periphery ; contractile vesicle single ; endoplast
spherical. Diameter 1-700". Embryos ovate, about three times as long
as broad, having a dense covering of cilia in addition to the scattered
suckers, which they equal or exceed in length.

HAB. — Fresh water, associated with Stylonychia mytilus.

The shorter proportions of the embryos of this species, as well as the distinct
specific nature of the host — accepting the form as parasitic — seem to distinguish it
from Spharophrya Urostylce last described. In accordance with the views originally
entertained but since abandoned by Stein, this form was presumed to be the acinete
embryo of Stylonychia mytilus.

Sphserophrya sol, Mecz. PL. XL VII. FIGS. 6 AND 7.

Body spherical ; tentacles numerous, protruding from all parts of the
periphery, extensile to a length exceeding the diameter of the body ; con-
tractile vesicle single ; endoplast ovate. Diameter 1-500".

HAB. — Parasitic within ParawKzcium aurelia.

The multiplication of the species by transverse fission accompanied by the
subdivision of the endoplast is recorded by Mecznikow.* Preparatory to this mode
of increase the body of the animalcule assumes an elongate-ovate contour. Being
unaware, apparently, of Mecznikow's work, E. Maupas has more recently proposed
to confer upon this type the title of Sph&rophrya paranuzciorum. A closely allied,
if not identical type has been observed by both Stein and Claparede and Lachmann,
as an endoparasite of Paramcecium bursaria, and has, in both instances, been treated
as an embryonic condition of that Holotrichous form.

Sphserophrya stentorea, Maupas. PL. XLVL FIG. 7-9.

Body subspheroidal, ovate or elongate, frequently with one or two annular
constrictions; the posterior end of the body bearing eight or ten short,
irregularly scattered, capitate tentacles, the opposite extremity usually
clothed with long fine cilia ; endoplast ovate, developed toward the anterior
region of the body; contractile vesicles two in number, located posteriorly to
the endoplast. Length 1-600".

HAB. — Fresh water, occurring as an endoparasite of the Trumpet Ani-
malcule, Stentor Rceselii.

This type was originally figured and described by. Stein as an embryonic
condition of the Infusorian with which it is found associated. It would seem highly

' Miiller's Archiv fur Anatomic u. Physiologic,' 1864.

GENUS TRICHOPHRYA. 8ll

probable that the examples having an elongate contour with cilia developed at their
anterior extremity, as chiefly figured by Stein, represent migratory conditions only or
zooids about to divide by transverse fission. If, on the other hand, this condition
should prove on further acquaintance to be typical of the adult state, it will be desirable
to establish a new genus for its reception, and the position it will occupy as an
annectant form between the Ciliate and Tentaculiferous classes will be highly
significant. A species closely resembling the present form, but possessing a some-
what larger number of tentaculate appendages, has been observed by Stein in con-
nection with Stentor cceruleus.

Sphaerophrya hydrostatica, Eng.

Body spherical, bearing numerous, thirty to forty, long, irregularly dis-
tributed, distinctly capitate tentacles ; contractile vesicles minute, variable
in number, supplemented by a large non-contractile gas-vacuole, having a
diameter of one-half that of the body, and which confers upon the animal-
cule remarkable buoyancy in the water. Diameter of body 1-300".

HAB. — Pond water, among Lemna, floating near the surface.

The possession of a large supplementary non-contractile vacuole, which appar-
ently contains air and thus renders the body of the animalcule remarkably light and
buoyant in the water, serves to distinguish the form from any of the preceding
species. The original account of this type was communicated by T. W. Engelmann
to the ' Zoologischer Anzeiger,' Bd. i., 1878.

GENUS IV. TRICHOPHRYA, C. & L.

Animalcules illoricate, ovate or elongate, resembing those of Podophrya,
but temporarily affixed in a sessile manner to various objects without the
intermedium of a supporting pedicle ; tentacles suctorial, variously dis-
tributed.

Trichophrya epistylidis, C. & L. PL. XL VI. FIGS. 12 AND 13.

Body elongate, flattened, bearing from four or five to as many as seven
or eight fascicles of capitate suckers which are distributed irregularly
throughout its length ; contractile vesicles numerous ; endoplast band-like,
curved. Long diameter 1-120".

HAB. — Fresh water, usually attached throughout its ventral surface to
various water plants, or to the branching pedicle of Epistylis plicatilis.

This Acinetan has been recently obtained in this country by Mr. John Badcock,
who in the first place submitted his drawings for the identification of the species to
the author. Subsequently, however, in figuring and describing it,* Mr. Badcock is
inclined to regard it as an immature condition only of the stalked species Podophrya
quadripartita rather than as an independent type. A careful examination of Mr.
Badcock's evidence has however failed to satisfy the author with respect to this
presumed identity, and the chief data upon which this result has been arrived at may be
thus stated. In the first place, no direct connection was established between these
two forms by Mr. Badcock. Trichophrya was first observed by him on some Conferva
taken from one of the ponds in the Victoria Park, and it was some weeks sub-
sequently that Podophrya quadripartita, also identified for Mr. Badcock by the
author, was found growing abundantly on a portion of this Algal that had been

: Notes on Acinetina," 'Journal of the Royal Microscopical Society,' Aug. 1880.

8l2 ORDER TENTACULIFERA-SUCTORIA.

transferred to a friend's aquarium, and where it had not improbably developed inde-
pendently. Of yet weightier import, however, are the facts that while Trichophrya has
normally half-a-dozen or more distinct fascicles of tentacula, Podophrya quadripartita,
its supposed mature form, has only four, and while the endoplast or nucleus in the
last-named type is simply ovate, in Trichophrya, as demonstrated by Claparede and
Lachmann, it is exceedingly attenuate or band-Jike. Mr. Badcock further testifies,
this being a new and important observation, that the tentacles of the Trichophrya in
their contracted state exhibit an apparent spiral plication, which is evidently due,
as shown by his drawings, to the existence of a delicate externally developed spiral
filament as observed by the author in Podophrya elongata and other species described
in this volume. No such histologic differentiation of the substance of the tentacles
is referred to in the case of Podophrya quadripartita, and that such does not exist
in this species the author is enabled to affirm through having received from Mr.
Badcock specimens for identification of the very examples he described, and sub-
jected them to a searching examination in both the living and preserved condition.
This circumstance of the essentially distinct histologic composition of their tenta-
cular appendages would of itself suffice to indicate the specific independence of these
two forms. It has yet to be stated, that Mr. Badcock himself records observing
the development of the adult Podophrya from ciliated embryos that were present in
the water, and which, as has been already observed by Biitschli and other investi-
gators, are produced by a process of internal gemmation from the parent. In the
series of examples examined by the author it was further found that the smallest
and youngest specimens possessed but one or two tentacular fascicles, four such
fascicles being the full complement only of the adult zooid. The intercalation of a
Trichophrya-X^ejt or multi-fasciculate phase as an embryonic state cannot therefore
be logically maintained. It is worthy of remark in this connection, that a variety of
species of Acinetidae frequently occur in company, a fact which is well calculated to
mislead the amateur investigator as to their true import and affinities. As an
illustration of this fact it may be mentioned that the author has recently received
from Dundee fragments of weeds upon which are thus associated the three very
distinct types Podophrya elongata, P. mollis, and Acineta mystacina, and in a similar
manner, through Mr. Thos. Bolton of Birmingham, examples of Acineta grandis, A.
lemnarum, A. mystacina, var. longipes, and Dendrosoma radians, growing on the same
or neighbouring branchlets of the weed Nitella. Mr. Badcock, finally, in his laudable
attempt to establish the identity between Trichophrya epistylidis and Podophr)a
quadripartita, figures as substantial evidence in the proof of his assumption * what
is an undoubted example of the loricate bifasciculate type Acineta lemnarum.
Trichophrya epistylidis, upon the weight of evidence submitted in these pages, is
hence unhesitatingly retained as a well-marked independent species. Among the
examples of this type examined by Messrs. Claparede and Lachmann an internally
developed ciliated embryo was on one occasion observed.

Trichophrya digitata, Stein sp. PL. XLVL FIGS. 10 AND u.

Body ovate, discoidal, adherent throughout the whole, or the central
portion only, of the under surface ; tentacles thick and digitiform, not
distinctly capitate, scattered irregularly over the entire free surface ;
contractile vesicle single ; endoplast band-like, sinuous. Length 1-360".

HAB. — Fresh water, on Entomostraca.

This species, originally described by Stein as the "gefingerte Acinete," was
believed by that authority to represent the embryonic or Acinete condition of some
higher ciliate Infusorium ; later on, however, it received from him the name of
Acineta digitata, and is referred to the present genus by Claparede and Lachmann.

'Journ. Roy. Mic. Soc.,' Aug. 1880, pi. xiv. fig. 6.

GENUS PODOPHR YA. 813

Neither in the text, nor in any of the numerous illustrations given by that authority,
from which our figure is borrowed, are the suckers shown to assume the extended
state with capitate extremities that characterize the typical Acineta, and under these
circumstances, it seems doubtful whether it should not be more accurately referred
to the family of the Ephelotidae. The Trichophrya Ophrydii of Claparede and
Lachmann, the equivalent of Stein's Acinete phase of Ophrydium versatile, would
seem to differ in no important respect from this species.

GENUS V. PODOPHRYA, Ehr.

Animalcules solitary, illoricate, globose, ovate, or elongate, attached
posteriorly to foreign objects by a more or less extensively developed rigid
pedicle ; tentacles suctorial, usually distinctly capitate, united in fascicles
or distributed irregularly over the surface of the periphery.

HAB. — Salt and fresh water.

The identification of the numerous species belonging to the genus Podophrya
may be greatly facilitated by dividing the entire series into two sections distinguished
respectively by the irregular or fasciculate disposition of their tentacles.

A. — TENTACLES IRREGULARLY DISTRIBUTED.
Podophrya fixa, Mull. sp. PL. XLVI. FIGS. 24-30.

Body spherical, attached to a slender and more usually sinuous pedicle,
the distal extremity of which is abruptly expanded, and whose length
rarely exceeds the diameter of the body ; tentacles numerous, slender,
distinctly capitate, not exceeding the body in length, distributed throughout
the surface of the periphery ; contractile vesicle single or double ; endoplast
elongate-ovate, subcentral. Length of body 1-400". HAB. — Fresh water.

This animalcule, identical with the Trichoda fixa of O. F. Miiller, was originally
regarded by Stein as both synonymous with Actinophrys sol, and as a transitional
Acinete condition of Vorticella microstoma. From Dujardin, who also relegated it
to the Radiolarian class, it received the title of Actinophrys pedicellata. In its
resting or encysted condition, PL XLVI. Fig. 28, the external cuticular layer,
becoming indurated, assumes a pyriform outline, ornamented by three or four pro-
minent transversely annular crests or ridges, the interspaces between which are, to a
greater or less extent, longitudinally striate. The presence of such cysts has been
detected by Engelmann among other food-matter within the parenchyma of Stylo-
nychia my'tilus, a circumstance which suggests the possibility of Spharophrya
stylonychii being the embryonic condition only of the present type, developed
through the breaking up into spore-like bodies of the encysted Podophrya.

Podophrya ferrum-equinum, Ehr. sp. PL. XLVI. FIGS. 19-22.

Body flattened, reniform, having a raised nipple-like protuberance in the
centre of the anterior surface ; tentacles irregularly distributed along the
anterior border ; pedicle very short, thick, and turgid, longitudinally striate,
its diameter nearly equal to that of the body of the animalcule ; contractile
vesicles numerous, forming a continuous row along the margin of the frontal
border; endoplast horseshoe-shaped. Greatest diameter of body 1-120".

HAB. — Fresh water, on Hydrophilns piceus.

8 14 ORDER TENTACULIFERA-SUCTORIA.

The species is to be distinguished from P. cothurnata, which it most closely
resembles, by the great proportional thickness of the foot-stalk, and the
protuberance on the frontal margin of the body. Zenker, who has recently studied
its development, reports that the free-swimming embryos exhibit a holotrichous
plan of ciliation. These embryos, after attachment, develop at first only a single
terminal or axial suctorial tentacle, which thus conveys to them a close resemblance
to the permanently mono-tentaculate genus Rhyncheta. Claparede and Lachmann,
who have referred this type to the present genus, indicate in their drawings the
production of an embryo by internal gemmation, which would seem, however, to
be ciliated on one only of its lateral surfaces ; preparatory to its liberation a
fissure-like aperture was observed to be developed in the wall of the parent body,
similar to that which has been subsequently observed by Biitschli and Wrzesniowski
of Podophrya quadripartita and Dendrocometes paradoxus.

Podophrya libera, Perty.

Body spherical; tentacles numerous, distinctly capitate, distributed
throughout the peripheral surface, their length, when extended, equalling
three or four times the diameter of the body ; pedicle slender, its length
equal to or slightly exceeding the width of the body; zooids often detached
and freely motile. Diameter of body 1-300." HAB. — Pond water.

This species, originally described by Perty, in its detached or free condition
only, has more recently been rediscovered by E. Maupas in the neighbourhood of
Algeria. This last-named investigator, being unable at the time to refer to Perty's
work, regarded it as a variety only of Podophrya fixa, and figured and described it
under the title of Podophrya fixa var. Algeriensis* but has since \ fully recognized its
claims for recognition as an independent species. This is more especially manifested
by the much greater relative length of the tentaculate appendages and the tendency
of the animalcules to abandon their stalks and lead a free roving life after the manner
of a Sphtzrophrya. It was observed by Maupas that, pending the transformation
from the fixed to the free-swimming state, the tentacles are withdrawn into the
substance of the parenchyma and become entirely obliterated, the body then
becomes elongate, and the cuticular surface more or less completely clothed with
fine vibratile cilia. In this condition the animalcule detaches itself and moves
freely in the water until, finding a locality more suited to its wants, it again fixes
itself by the posterior extremity. Suctorial tentacles are now protruded as
formerly from the inner parenchyma, the cilia are reabsorbed into the cuticular
layer, and the animalcule becomes indistinguishable from its pristine characteristic
state. In addition to the motile condition just described, it not unfrequently
happens that Podophrya libera detaches itself from its pedicle without the develop-
ment of cilia, and creeps from place to place with the assistance of its adhesive
tentacles.

Podophrya cylindrica, Perty. PL. XLVIII. FIG. 20.

Body elongate-cylindrical, about four times as long as broad, mounted
on a short slender pedicle ; tentacles distinctly capitate, developed irregu-
larly from the distal extremity of the body only ; endoplast elongate
ovate, subcentral ; contractile vesicles not observed. Length 1-250".

HAB. — Fresh water, on Lemna.

This species, originally found in Switzerland and figured and described by
Perty, has been recently rediscovered among Lemnce in the neighbourhood of St.
Petersburg by C. von Mereschkowsky.

* ' Archives de Zoologie Experimentale, torn, iv., 1876. f Ibid., torn, ix., 1881.

GENUS PODOPHRYA. 815

Podophrya Lyngbyi, Ehr. sp.

Body globose or pyriform ; tentacles capitate, scattered irregularly over
the entire distal extremity ; pedicle thick, two or three times the length of
the body ; contractile vesicles two in number ; colour yellowish-brown.
Length 1-500". HAB. — Salt water, on marine algae and Serttdaria.

Embryos of this species, as observed by Claparede and Lachmann, are
released from the parent body in a form identical, except for the absence of a
footstalk, with the latter ; or, in other words, they may be said to correspond in this
early state with the adult condition of the genus Sphczrophrya. By Ehrenberg this
type is figured and described under the title of Acineta Lyngbyi.

Podophrya Steinii, C. & L. PL. XLVI. FIGS. 58 AND 59.

Body pyriform, tapering posteriorly ; tentacles numerous, slender, not
conspicuously capitate, distributed irregularly over the entire peripheral
surface ; pedicle about equal in length to the body, slender at its base, very
widely expanded at its point of junction with the body, finely striate longi-
tudinally, and coarsely wrinkled transversely ; contractile vesicles multiple ;
endoplast central, radiately branching. Length 1-150".

HAB. — Fresh water, on Dytiscus marginalis.

This species was first figured and described by Stein as an Acineta-phase of
Opercularia articulata, but was afterwards invested with the above specific title
by Claparede and Lachmann. Engelmann has shown that each contractile vesicle
in this type possesses a distinct tubular outlet.

Podophrya cothurnata, C. & L. sp.

Body discoidal, flattened, oval or reniform, pedicle very short and thick,
less than one-half the length of the body ; tentacles not fasciculate, forming
a crown at the anterior extremity ; contractile vesicles numerous, disposed
in a continuous row around the periphery ; endoplast horseshoe-shaped or
band-like. Length 1-240".

HAB. — Fresh water, on various species of Lemna and Callitricha.

This form is identical with the Acineta cothurnata of Weisse, and the " diadem-
artige Acinete " of Stein . In Pritchard's ' Infusoria ' it is embodied under the
title of A. diademiformts, but is confounded with the Podophrya fcrrum-equinum
previously described.

Podophrya conipes, Mereschk. PL. XL VI 1 1 A. FIG. 4.

Body subspheroidal or pyriform, soft, plastic, and frequently with
irregular prominences and depressions ; tentacles with conspicuous aceta-
bulate extremities, not very numerous, produced in young individuals from
the anterior region only, but extending in the adult zooids irregularly from
all parts of the periphery, slender, and exceeding the length of the body
when fully exsert ; pedicle five to eight or ten times longer than the body,
narrowest and pointed at its proximal extremity or point of attachment,
and gradually increasing in diameter as it approaches its junction with the

8l6 ORDER TENTACULIFERA-SUCTORIA.

body, finely striate transversely throughout its length, and usually bearing
two conspicuous central annuli ; contractile vesicle single, subcentral ; endo-
plast elongate-ovate. Length of body 1-240" to 1-144".

HAB. — Salt water : White sea (Mereschkovvsky), on Rhodospermous
Algae (Ptilota and Ceramiuni), at various depths.

This characteristic form which, excepting for its tapering and transversely striate
pedicle, most nearly approaches P. Lyngbyi, is regarded by Mereschkowsky, in
common with Tintinnus Ussowi, as belonging essentially to the Arctic zoological zone.

Podophrya limbata, Maupas. PL. XLVIII. FIG. 5.

Body subspherical, with a usually more attenuate posterior prolongation,
the periphery frequently surrounded by an evenly developed, tenacious,
hyaline, gelatinous film ; tentacles slender, irregularly distributed, distinctly
capitate, from ten to fifteen in number, their length when extended equal to
about one and a half times the diameter of the body ; pedicle transparent,
rectilinear and even throughout the greater portion of its length, but ex-
panding abruptly at the distal extremity to four or five times its normal
width, and thus forming a platform of support to the animalcule's body ;
parenchyma yellow or colourless ; contractile vesicle single, laterally located ;
endoplast ovate, subcentral. Length 1-850". HAB. — Salt water.

This species is reported by Maupas* as occurring on Hydroid zoophytes both at
Roscoff, Brittany, and in the neighbourhood of Algiers. Its discoverer proposes
to identify the frequently developed peripheral gelatinous film with the external
gelatinous layer that surrounds the denser body-mass or so-called " central capsule "
of the typical Radiolaria. This external film in Podopkrya libera was observed to
be of exceedingly tenacious consistence, readily entangling foreign particles held
suspended in the surrounding water, and thus when gathered from a turbid source
was so opaque as to preclude a distinct view of the body proper. Possibly this
secretion of a mucilaginous investment may be a preliminary step towards the process
of encystment.

Podophrya infundibulifera, Hartog.

Body subspherical or pyriform, mounted on a short rigid pedicle ;
tentacles varying from six to fourteen in number, distributed throughout
the peripheral surface ; when at rest, short, thick, with obtusely rounded
distal terminations, and a circular constriction a little below the joint ;
when extended in quest of food dilated funnelwise in this region, and
exhibiting throughout their length equidistant circular wrinkles. Con-
tractile vesicle single, contracting at intervals of 34" to 44''. Endoplast
spherical. Dimensions unrecorded.

HAB. — Fresh water, on Cyclops gigas, especially females, on and about
the bases of the oral appendages.

This species is briefly described by Mr. Marcus Hartog in the 'Proceedings of
the Manchester Literary and Philosophical Society,' vol. xix., 1880. It is distin-
guished from Podophrya eyclopum by the scattered plan of distribution of the
tentacles and by the non-capitate aspect they ordinarily exhibit.

* "Contribution k I'Etude des Acinetiens," 'Arch, de Zool. Exp.,' torn, ix., 1881.

GENUS PODOPHR YA. 817

Podophrya Wrzesniowskii, S. K. PL. XLVI. FIG. 31.

Body elongate-ovate or elliptical, about twice as long as broad ; pedicle
thick, subcylindrical, increasing slightly towards its point of junction with
the body, internally longitudinally, and externally finely transversely striate ;
tentacles very minute and slender, distinctly capitate, distributed irregularly
over the entire peripheral surface, but most abundant anteriorly ; contractile
vesicles two or three in number ; endoplast irregularly ovate ; numerous
minute spherical vacuolae containing refringent granules usually present
towards the posterior extremity. Length of body 1-400".

HAB. — Fresh water, on the elytra of the aquatic Coleopteron Hydroporus
picipes.

This species has been recently figured and described by Wrzesniowski * and
referred by him to the Podophrya Leichtensteinii of Claparede and Lachmann, and
Acineta (Podophrya) hyphydri of Stein. A comparison, however, of the accounts and
illustrations of these respective forms has convinced the author that we have in the
present instance a type differing considerably from the one last-named. The
characters which serve to distinguish this present form from Stein's species may be
thus summarized : — The body, while exhibiting a somewhat similar but at the same
time more regularly elliptical contour, is mounted on a pedicle which does not
expand widely at its point of junction with the body as in P. Leichtensteinii, and
whose surface is finely striate transversely instead of coarsely wrinkled. The
characters afforded by the tentacula are still more decisive, for while in Stein's
species they exhibit a distinct fascicular arrangement and are confined to the anterior
region of the body, in the present one they are distributed without any definite
arrangement throughout the peripheral surface ; individually examined, the irregu-
larly scattered tentacles are further much more minute, their proportionate size
with relation to the body of the animalcule being about half that of P. Leichtensteinii.
These dimensions, associated with their distinctly capitate extremities, contrast in a
marked manner with the slender non-capitate appendages of the species with which
Wrzesniowski has proposed to identify it. The presence of the numerous vacuolae
with their enclosed refringent granules appears to afford an additional and permanent
feature of this species that would scarcely have been overlooked by Stein in his
account of P. Leichtensteinii. Being unable in face of these highly divergent
characteristics to unite under one specific title the two forms here submitted to
comparison, the author has much pleasure in associating with the type requiring
a new specific title the name of the investigator to whom we are indebted for its>
discovery, and who has proved himself so industrious a worker in this field of
biological research. Wrzesniowski records, in connection with the contractile
vesicle of this type, a distinct tubular exit similar to that of Dendrocometes paradoxus,
Acineta opercularice, and other representatives of the same order, as also that the
same vesicle is not always constant in its form or position, sometimes breaking up
in a fragmentary manner. This latter circumstance is rightly held as yielding con-
clusive evidence of the non-possession by this structure of a distinct membranous
wall, or its occupation of a distinctly differentiated interspace in the substance of
the parenchyma. Under high magnification, as in P. Leichtensteinii, the species
presents a well-developed cuticular layer, but this membrane is not separated from
the subjacent parenchyma so as to constitute an independent external pellicle or
lorica, as among the true Acinetcz to which Wrzesniowski has proposed to refer it.

1 Zeitschrift fiir Wissenschaftliche Zoologie,' Bd. xxix. p. 268, 1877.

VOL. II. 2 A

8l8 ORDER TENTACULIFERA-SUCTORIA.

B. — TENTACLES FASCICULATE.
Podophrya carchesii, C. & L. PL. XLVIIL FIG. 23.

Body subspheroidal, ovate, or irregular in shape, the distal or anterior
extremity rounded, bearing on one side a single fascicle of tubular suckers ;
pedicle as short as, or shorter than one-half the length of the body, usually
asymmetrically inserted ; contractile vesicle single, situated near the anterior
extremity. Length of body 1-950" to 1-350".

HAB. — Fresh water, usually attached in social colonies to the stalks
of Carchesium polypinum.

The author obtained examples of this type developed in great abundance on
the branching pedicle or zoodendrium of Epistylis flavicans, remitted from the
neighbourhood of Stourbridge, Worcestershire, by Mr. Thos. Bolton, in April 1874.

Podophrya cyclopum, C. & L. PL. XLVI. FIG. 23.

Body ovate or globular, tapering posteriorly, the anterior extremity
rounded or lobate, bearing from two to four fascicles of capitate suckers ;
pedicle usually very short, rarely exceeding one-third of the length of the
body ; contractile vesicles one or two in number ; endoplast oval. Length
of body i -800" to 1-300".

HAB. — Fresh water, mostly parasitic on Cyclops quadricornis and other
Entomostraca, but occasionally on aquatic plants.

This species was originally figured and described by Stein under the title of
" Acinete der Cyclopen" being at that time regarded by him as the embryonic form
of some higher ciliate animalcule.

Podophrya Leichtensteinii, C. & L.

Body ovate or pyriform ; tentacles slender, not distinctly capitate,
forming two antero-lateral fascicles ; pedicle about one-half the length of
the body, widely expanded at the point of junction with the latter, tapering
posteriorly, transversely wrinkled ; endoplast oval, subcentral. Length
1-300". HAB. — Fresh water, on aquatic Coleoptera.

This species, first described by Stein as the Acineta-phase of Opercularia Leich-
tensteinii, subsequently received from him the title of Acineta hyphydri. Claparede
and Lachmann had, however, in the interim conferred upon it the name above
given, and which necessarily takes the precedence.

Podophrya phryganidarmn, Stein sp.

Body pear-shaped, flexible, slender and tapering somewhat abruptly
posteriorly ; pedicle about half the length of the body, more or less curved,
narrowest at its point of attachment, increasing slightly in diameter as it
approaches its point of union with the body, finely striate longitudinally ;
tentacles long and fine, not distinctly capitate, forming two antero-lateral
fascicles ; contractile vesicle single, anteriorly situated ; endoplast elongate-
ovate or band-shaped. Length of body 1-240".

GENUS PODOPHRYA. 819

HAB. — Fresh water, associated with Epistylis branchiophila, on the larvae
of Phryganidae.

In accordance with his original views concerning the nature and affinities of
the Acinetidae, this type was originally accepted by Stein as a developmental form
of theVorticellan Epistylis branchiophila, upon whose pedicle it occurs as a parasite.
In the first volume of his ' Organismus ' it receives from him the title of Acineta
phryganidarum, but the entire absence of any trace of a lorica or distinct pellicular
investment necessitates its relegation to the genus Podophrya ; the slender pointed,
non-capitate tentacles of this species, in addition to the shorter flexuose pedicle,
serve to distinguish it from P. pyrum or any other of its more near allies.

Podophrya infusionum, Stein sp.

Body subspheroidal or pyriform, attached by its more attenuate
posterior extremity to a short sinuous pedicle, whose length rarely exceeds
one-half that of the body ; tentacles short, distinctly capitate, developed
in two lateral fascicles ; contractile vesicles two in number ; endoplast
elongate-ovate, subcentral. Length of body 1-350".

HAB. — Pond water and infusions.

This species was originally figured by Stein* as an elongate variety only of
Podophrya fixa, but has an independent position awarded to it under the title
of Acineta infusionum in the first volume of his more recent treatise.t It may be
readily distinguished from the Podophrya named, in addition to the more elongate
contour of the body, by the fasciculate instead of the distributed disposition of the
tentacles.

Podophrya astaci, C. & L. PL. XLVI. FIGS. 14-17.

Body elongate, subquadrate, scarcely twice as long as broad ; tentacles
forming two groups at the anterior and posterior extremities ; pedicle thick,
transversely wrinkled, gradually enlarging from its point of attachment to
that of its junction with the animalcule's body ; contractile vesicles numerous,
irregularly distributed ; endoplast oval, central. Length 1-300".

HAB. — Fresh water, on the river crayfish (Astacus fluviatilis).

This species is figured and described by Stein under the name of " Adnete des
Flusskrebses." From Podophrya elongata, which it somewhat resembles, it may be
distinguished by the absence of the two median lateral fascicles of suckers and by the
tapering or conical contour of the pedicle.

Podophrya pyrum, C. & L.

Body pyriform, attenuated posteriorly, the rounded and inflated
anterior extremity bearing one apical and two lateral fascicles of
capitate tentacles ; pedicle from one to one and a half times the length of
the body ; contractile vesicles two in number, one near the anterior and
the other adjacent to the posterior extremity; colour brown, opaque;
endoplast oval, subcentral. Length of body 1-150".

HAB. — Fresh water, on Lemna trisulca.

* 'Die Infusionsthiere auf ihre Entwickelungsgeschichte,' 1854.
t ' Der Organismus der Infusionsthiere,' torn. i. p. 48, 1859.

2 A 2

820 ORDER TENTACULIFERA-SUCTORIA.

Podophrya quadripartita, C. & L. PL. XLVI. FIG. 18.

Body more or less ovate, tapering posteriorly, the anterior extremity
divided into four blunt rounded lobes, each of which bears a fascicle of
tubular suckers ; pedicle elongate, from one to one and a half times the
length of the body, expanding slightly towards its point of junction with
the body ; contractile vesicles varying in number from one or two to as many
as five or six ; endoplast oval, central. Length of body 1-300" to 1-200".

HAB. — Fresh water, on Epistylis plicatilis ; also attached to various
water plants and to Paludina and other fresh-water Mollusca.

This form is identical with Stein's originally supposed Adneta-pha.se of Epistylis
plicatilis, afterwards receiving from him the name of Acineta quadriloba, but which
has necessarily to give place to the prior one of Claparede and Lachmann here
employed. Internal embryos of two sizes are, according to Claparede and Lach-
mann, developed in this species : larger ones which enclose a portion only of the
parent endoplast, and are liberated, according to Biitschli, through a specially
developed orifice, as in the case of Dendrocometes paradoxus ; and smaller ones,
to the number of sixteen or twenty, produced through the subdivision of the entire
endoplastic mass. In both cases the free-swimming gemmules at the time of libera-
tion exhibit a peritrichous type of ciliation, having an equatorial girdle supplemented
by an anterior tuft of cilia. The number of contractile vesicles which characterize
the parent form are found to be hereditarily represented in this embryonic phase.
The endoplast, at the time of partition, as observed by Biitschli, exchanges its
customary granular structure for a striate or fibrillate one, assuming its normal aspect
again after the birth of the embryo. Among the innumerable examples of this
species developed on a species of Conferva, recently remitted to the author by Mr.
Badcock, and referred to in the account given of Trichophrya epistylidis, it was
observed that the posterior moiety of the body was in many instances very attenuate,
not exceeding twice the diameter of the adjacent pedicle, and while in some cases the
transition from the thick anterior to the attenuate posterior region was abrupt, in
others the attenuation was gradual and uniform. Specimens preserved with a one
per cent, solution of osmic acid were found to retain their characteristic form in a
most remarkable manner, the central ovate endoplast being furthermore by the
application of this reagent most conspicuously developed. In their earlier pedi-
cellate condition the zooids of this species possess but a single fascicle of tentacles
which is shortly replaced by two, the full complement of four such bundles being
characteristic only of the adult state. The suggested relationship of Trichophrya
epistylidis to Podophrya quadripartita is discussed in the account given of that
species.

Podophrya elongata, C. & L. PL. XLVIII. FIGS. 21 AND 22.

Body elongate, subfusiform, five or six times as long as broad, bearing a
fascicle of suckers at the anterior extremity, one on each side at the posterior
extremity, and two oppositely disposed lateral groups ; pedicle thick, even in
width, longitudinally striate and often transversely plicate, usually about
one-third the length of the body, but occasionally greatly exceeding these
proportions ; contractile vesicles multiple, one larger one frequently deve-
loped near the apical extremity, and other smaller ones irregularly distri-
buted; endoplast band-like, vertical. Length 1-120".

HAB. — Fresh water, on the mollusc Paludina vimpara and various
water plants.

GENUS PODOPHR YA. 821

Examples of this species were received by the author as recently as November
1 88 1, growing in tolerable abundance in company with Acineta mystacina and
A. lemnarum on Ranunculus and other water-weeds from the neighbourhood of
Dundee, remitted by Mr. John Hood. As first figured and described by Claparede
and Lachmann, the species of mollusc named in the foregoing diagnosis is cited as
the only habitat ; the fact, however, that this type is restricted to a much more
southern area suffices to indicate that the infusorian species is not strictly a com-
mensal of Paludina. As examined by the author, the tentacles of Podophrya elongata,
were found, in their contracted state, even under moderate enlargement, to be distinctly
annulate in a spiral direction, and on being submitted to the relatively high magnifica-
tion of six or eight hundred diameters presented the aspect given at PI. XLVIII.
Fig. 22, the spiral element being thus demonstrated to consist of a spiral crest or
ridge of granular consistence, developed externally to the shaft of the tentacle, its
convolutions becoming more widely separated or attenuate until vanishing with the
extension of the tentacle, and the more closely approximated and thickened in pro-
portion to its contraction. The function of this crest-like element is apparently
intimately connected with the contractile movements of the tentacle, being in this
manner analogous to the spirally disposed fibrilla of the stalk of a Vorticella^
and also histologically and functionally homologous with the spiral granular ridges
developed on the external surface of the proboscis-like appendage of the genus
Ophryodendron.

Podophrya mollis, S. K. PL. XLVL FIGS. 53-56.

Body highly flexible, usually more or less triangular in outline when
expanded, sometimes ovate or pyriform, tapering posteriority, bearing two
antero-lateral fascicles of conspicuously capitate tentacles ; pedicle slender,
about twice the length of the body, straight, and even throughout ; con-
tractile vesicles one or two in number ; endoplast ovate. Length of body
i-iooo" to 1-240". HAB. — Pond water, on various aquatic plants.

Excepting for the entire absence of the separate investing pellicle or lorica this
type corresponds closely in contour and habits with Stein's " Acineta lemnarum"
originally regarded by that authority as a developmental condition only of Vorticella
nebulifera. The author has met with it abundantly on Lemna and other aquatic
plants, and on one occasion witnessed the process of transverse fission which as
manifested in this instance does not appear to have been previously recorded among
the representatives of this group. As a prelude to this process of fission two of the
tubular tentacles were extended to a great length, until finding a suitable fulcrum
for support they become firmly adherent to it ; within a short interval these two
tentacles coalesced, and becoming indurated, constituted as it were a second pedicle
joined on to the anterior extremity of the animalcule : the body of the zooid mean-
while grew more attenuate, and a considerable portion of the substance of its soft
plastic parenchyma passed over towards the newly formed pedicle. A constriction
now appeared in the centre of the body between the two attenuate extremities and
gradually deepened until a perfect separation was effected, the newly formed
product of this fission thus commencing its independent existence with an attached
pedicle and organization as complete as the zooid of which it but a short while
previously formed merely a constituent part. At PI. XLVI. Figs. 55 and 56 repre-
sentations of drawings made during the progress of this fissive process are herewith
reproduced. The stage represented by Fig. 56, if unaccompanied by the expla-
nation here given might be easily interpreted for an act of conjugation. This
species of Podophrya is remarkable among the other representatives of the same genus
for its great elasticity, the body assuming various attitudes on its stem and under-
going considerable modifications in external contour. When abandoning its more
normal triangular-shape for an ovate or pear-shaped outline it presents a close

822 ORDER TENTACULIFERA-SUCTORIA.

resemblance to the Podophrya pyrum of Claparede and Lachmann ; the three fasci-
culi of suckers serve however to distinguish that species from the present one.

Podophrya Buckei, S. K.

Body elongate, slender, subcylindrical, bearing two antero-lateral fascicles
of distinctly capitate tentacles ; not possessing a distinct pedicle but affixed
basally by a simple contracted sucking-disk ; contractile vesicle anteriorly
located ; endoplast subcentral. Dimensions unrecorded.

HAB. — Fresh water.

This species, which has recently been briefly described by E. Bucke, * without
any accompanying title, must be accepted as a new species, apparently most closely
resembling Podophrya eylindrica and P. elongata in the contour of its body, but
differing distinctly from either of these types in the character of its basal supporting
element and in the disposition of its tentacles. With reference to the acetabuliform
modification of its basal region it will be probably found desirable hereafter to make
this species the type of a new genus.

GENUS VI. HEMIOPHRYA, S. K.
(Greek, hemi, half; ophrys, eyebrow.)

Animalcules stalked, illoricate, bearing tentacles of two orders, the one
series being suctorial, as with the ordinary Acinetidae, the others simply
prehensile ; multiplying chiefly by exogenous terminal gemmation ; the
endoplast usually more or less irregularly branched. Inhabiting salt water.

This genus is instituted by the author for the reception of the Podophrya gemmi-
para of Hertwig, a form which differs conspicuously from the typical members of the
genus Podophrya in the dimorphic character of the tentaculate appendages, which
are differentiated for the two separate functions of prehension and food-ingestion.
With reference to the presence of supplementary tentacula having a simply pre-
hensile function, it forms an interesting and important link between the two groups
of the Suctoria and Actinaria, as recognized in this treatise. Two additional species
recently described by M. Fraipont, one by M. Koch, and two by E. Maupas, have
to be added to the single form upon which the genus was first established. Maupas,
the most recent investigator of this group of organisms, has, in his recent very
important memoir,t fully recognized the desirability of creating a new generic name
for Hertwig's type, and, although having previously selected an independent one,
has courteously substituted for it the title proposed by the author, though necessarily
without any diagnostic details, in the earlier pages of this work (see pp. 66, 97,
and 215). It may be further mentioned here, however, that the new generic name
of Hemiophrya, with a figure and brief description of the peculiarities of this species,
were included by the author in a paper entitled " Notes on Marine Infusoria,"
communicated to the meeting of the Birmingham Natural History Society, held on
January 2oth, 1880, such paper, with illustrations, being published both in the ' Mid-
land Naturalist ' for March and in the Society's Transactions for that year. As rightly
indicated by Maupas, Hemiophrya differs from Podophrya in several important
details, irrespective of those furnished by the character of the tentacles.

In this connection, attention may be more especially directed to the phenomena
of reproduction, which in all of the several known species takes the form of
external or exogenously produced buds or gemmules in place of by endogenous

* " Die Acineten im Aquarium," ' Der Zoologische Garten,' Jahrgang xv., 1875.
t "Contributions a 1'Etude des Acinetiens," 'Archives de Zoologie Experimentale,' torn. ix.
No. III. November 1881.

GENUS HEMIOPHRYA. 823

embryos, as obtains in the genus Podophrya. The nucleus or endoplast has a
tendency likewise to become branched or complex, sending out diverticula into
the substance of the anteriorly produced gemmules, instead of being simply ovate
as in the last-named genus. A third more subordinate but at the same time note-
worthy distinctive feature, pointed out by Maupas, is afforded by the mode of
union between the animalcule's body and its supporting pedicle. In Podophrya no
abnormal feature is discernible, but in Hemiophrya it mostly happens that the
pedicle seems to be continued into the substance of the body, such appearance
being due to the fact that the body is hollow or invaginated at this point, and thus
overlaps the adjoining regions of the pedicle.

Hemiophrya gemmipara, Hertwig.
PL. XLVI. FIGS. 48-51 AND PL. XLVII. FIGS. 9-14.

Body contractile and somewhat variable in form, usually cup-shaped or
subpyriform, widest anteriorly and tapering gradually towards its point of
junction with the pedicle; tentacles protruded in a crown-like mannerfromthe
entire anterior border ; those of a suctorial character subcentrally developed,
short, usually five or six in number ; the prehensile tentacles three or four
times as numerous, their length when extended exceeding the diameter of
the body, their external surface granulate in a spiral direction ; pedicle about
four times the length of the body, most slender at its point of attachment,
and gradually increasing in diameter towards its distal extremity, hollow
interiorly, its external surface both transversely and longitudinally striate ;
contractile vesicles two or more in number, situated towards the anterior
border ; endoplast usually scimitar-shaped, subsequently more or less rami-
fied ; multiplying by the production of gemmules from the anterior border,
which are liberated in the form of oval embryos clothed with cilia on one side
of the body only, after the manner of the Hypotrichous Ciliata ; parenchyma
transparent or enclosing reddish-brown granular matter. Length of body
1-400" to 1-125". HAB. — Salt water.

This animalcule, which is figured and described at length by Dr. R. Hertwig, in
the ' Morphologisches Jahrbuch,' Band i., 1875, under the title of Podophrya
gemmipara, yields many points of interest. In its possession of certain tentacles, which
are not suctorial, but simply prehensile, it may be regarded as a transitional form
between the families of the Acinetidae and Ephelotidae, while the released embryos
in their hypotrichous form of ciliation correspond closely with those of Acineta
cucullus and Dendrocometes paradoxus. Of these ciliate embryos, it not unfrequently
happens that as many as six or eight are clustered upon the anterior border, and
into each one of these there divaricates a prolongation of the parent nucleus, which
is constricted off and retained within the body of the embryo prior to its liberation
into the surrounding water. The supplementary or simply prehensile tentacles of
this species present, in addition to their non-possession of suctorial terminations, a
marked distinction, as seen under high magnification, from the more characteristic
ones of their class. The boundary walls of these appendages, instead of being
smooth and even, are more or less coarsely nodular, the component particles of
externally developed granular protoplasm being usually disposed in a spiral manner
around the central axis. These prehensile tentacular appendages would seem to
correspond to some extent with the non-suctorial and muricate tentacula of Actino-
cyathus ddaris. In this respect the structure of the prehensile tentacles is shown to
correspond essentially with that of the ordinary suctorial appendages of such a type
as Podophrya elongata, in which, as recently observed by the author, a very distinct

824 ORDER TENTACULIFERA-SUCTORIA.

granular protoplasmic crest is developed in a spiral fashion around the central shaft
of the tentacle.

Hemiophrya gemmipara would appear to enjoy a relatively cosmopolitan dis-
tribution, having been met with by Hertwig at Roscoff, by Lieberkuhn in the
Grand Canal at Venice, and by Maupas in the vicinity of Algiers, while the
author has collected it in considerable abundance in the Channel Islands and on
the Devonshire, Cornish, and North Wales coasts. Among certain of the examples
derived from the last-named locality in August 1881, it was observed that the
embryos produced by gemmation from the anterior border of the animalcule's body
were of an irregular pyriform contour, and provided with short tentacles in addition
to, or in place of, a more or less conspicuously developed ciliary covering. A
somewhat similar observation has been made by M. C. Robin in connection with
specimens gathered at Con9arneau,* but in this case the gemmules were simply
tentaculiferous, and are treated of by this authority as an independent form of bud.
It would seem more probable, however, that these abnormal gemmules represent
instances in which the typical ciliated embryos have undergone their metamorphoses
while still adherent to the parent's body, in place of becoming severed from it during
the initial or simply ciliate condition, as more usually happens ; this interpretation is
substantially supported by the evidence of an intermediate condition, as observed by
the author. The successive phases undergone by the detached ciliated embryos
during the growth to the adult stalked condition, as observed by M. Robin, are well
illustrated at PI. XLVII. Figs. 11-14. It must be mentioned that this investigator
proposes to identify this species with the Podophrya Lingbyi of Ehrenberg and
Claparede and Lachmann ; as pointed out, however, by M. Maupas,f the last-
named type is a normal species of Podophrya, having relatively short capitate ten-
tacles only. Prof. E. Perceval Wright has recently reported the present species from
the Irish coast.

Hemiophrya Benedeni, Fraip. sp.
PL. XLVII. FIG. 15 AND PL. XLVIII. FIGS. 30 AND 31.

Body subquadrangular or pyriform, widest anteriorly, tapering towards
its point of junction with the pedicle ; prehensile tentacles numerous, about
forty in number, their length when extended averaging twice the diameter
of the body, their substance spirally fibrillate ; suctorial tentacles short, sub-
conical, their extended length not exceeding one-third of the diameter of
the body; pedicle quadrangular, from ten to fifteen times the length of
the body, its central or medullary substance transversely striate, its external
layer transparent and homogeneous ; parenchyma opaque dirty yellow ;
contractile vesicles four in number, two developed in each lateral body-half ;
endoplast originally horseshoe-shaped, becoming with age diversely ramified,
rendered visible only by the action of reagents ; increasing by terminal
gemmation. Length of body 1-300". HAB. — Salt water.

This species differs substantially from Hemiophrya gemmipara in the greater
relative length and quadrangular contour of the pedicle, in the greater numerical
development of the prehensile tentacles, and in the shorter conical contour of those
endued with a suctorial function. Examined with a sufficiently high power, it was
found that the whole length of the prehensile tentacles, from a short distance from
their base, was traversed by a very delicate spiral filament, which, according to
M. Fraipont, is developed on the internal surface of the membranous walls of the

* ' Journal de 1'Anatomie et Physiologic,' 1879.

t ' Archives de Zoologie Experimentale,' torn, ix., 1881.

GENUS HEMIOPHRYA. 825

tentacle, in place of forming a crest-like ridge upon its external surface, as obtains
in H. gemmipara. The embryos produced by terminal gemmation are, as in
Hertwig's species, hypotrichously ciliated, and manifest closely identical develop-
mental phenomena. It is recorded that the bodies of the adult animalcules easily
become detached from their supporting pedicles; and on one occasion a ciliated
embryo was observed to crawl up and down, and finally affix itself to the summit of
a deserted pedicle, and there develop to the adult form. This circumstance is
accepted by M. Fraipont as explanatory of the frequent occurrence of fully
developed pedicles having only very minute attached zooids. A similar result is,
nevertheless, not unfrequently brought about in allied species through the ordinary
process of transverse fission.

Hemiophrya tmncata, Fraipont sp. PL. XLVIII. FIG. 46.

Body elliptical or subquadrangular ; pedicle massive and irregular, three
or four times the length of the body ; usually for some little distance
equalling the breadth of the body in thickness, and thence tapering
gradually to its point of attachment, its distal end articulate or transversely
plicate; suctorial tentacles developed from the centre of the distal region of
the body, the prehensile tentacles numbering in adult zooids as many as
fifty or sixty, more slender and prolonged than those of the suctorial series,
and around which they are chiefly disposed in a fringe-like manner;
parenchyma densely granular ; endoplast and contractile vesicle not
observed. Length of body 1-500".

HAB. — Salt water, on the Zoophyte Sertularia cupressina.

This form is described by M. Fraipont as a species of Podophrya from specimens
collected and preserved at Ostend, by Professor Ed. Van Beneden. In the massive
character of the pedicle it differs in a marked manner from the two preceding species,
but at the same time somewhat resembles in this respect the Podophrya Steinii of
Claparede and Lachmann. In an encysted example observed the body-substance
had become subdivided into a mass of granular spore-like spherules.

Hemiophrya microsoma, Maupas.

Body subspherical or ovate, attached to a very long, cylindrical,
irregularly sinuous pedicle, the breadth of which is greatest at the distal
end, there equalling one-quarter or one-half the diameter of the body, and
gradually tapering towards its point of attachment, its length varying
from four or five to as much as eighteen times that of the body ; suctorial
tentacle single, subcentral, originating from the centre of the body ; pre-
hensile tentacles short, not exceeding eight or ten in number, developed
superficially, and irregularly scattered, their distal ends slightly inflated ;
contractile vesicle single or double \ endoplast elongate, irregularly nodu-
late. Length 1-900". HAB. — Salt water : Algiers.

The short dimensions of the body with relation to its supporting pedicle,
combined with the very small proportionate number of the suctorial tentacles, sepa-
rates this type very distinctly from its congeners. From the fact recorded by Maupas
that the tentacles belonging to the prehensile series are slightly dilated instead of
subulate at their free extremities, this species would seem to represent an annectant
form between the typical members of the two genera Hemiophrya and Podophrya.

826 ORDER TENTACULIFERA-SUCTORIA.

Hemiophrya Thouleti, Maupas. PL. XLVIII. FIG. 19.

Body usually subquadrate or trapeziform in lateral aspect, the anterior
border being the wider ; pedicle not exceeding one-half the length of the
body, thick and inflated superiorly, abruptly constricted at its proximal or
adherent extremity ; suctorial tentacles short, ranging from two to five in
number, originating distinctly from the internal or endoplasmic region ;
prehensile tentacles more numerous, attenuate, superficially developed,
grouped in an irregular circle round the anterior border of the body,
verrucose and granulate when contracted ; contractile vesicle single or double,
anteriorly located ; endoplast subcentral, horseshoe-shaped or irregular,
often nodulate ; parenchyma brownish-yellow. Length of body 1-900"
to 1-500". HAB. — Salt water.

This species was obtained on one occasion only by E. Maupas in the neigh-
bourhood of Algiers, the animalcules being in that instance, however, so abundantly
developed as to literally cover the Hydroid polyps which gave them support.
Hemiophrya gemmipara was found sparingly in its company. Multiplication by
abundant external gemmation after the manner of the last-named species was
observed.

Hemiophrya crustaceorum, Haller sp. PL. XL VII. FIG. 8.

Body subspherical, of a yellowish hue, mounted on a long cylindrical
pedicle, whose greatest width, at the distal end, equals one-half the
diameter of the body, and thence tapers off to its point of attachment, its
total length averaging eight or ten times that of the body, its external
surface throughout the anterior half finely striate transversely, that of the
succeeding or basal moiety entirely smooth ; suctorial tentacles short,
few in number, distinctly capitate, those of the prehensile series attenuate,
very numerous, exceeding the body in length, the external surface sub-
spirally granulate, radiating from all parts of the periphery ; reproductive
granules developed in great abundance over the entire surface of the body,
but chiefly upon the anterior body-half. Length of body 1-300".

HAB. — Salt water, upon a species of Caprella.

This type has been recently described incidentally as a species of Podophrya, by
G. Haller, in an article devoted to the morphology of the Lemodipodous Crustacea.*
In its general contour it to some extent resembles the Podophrya conipes of
Mereschkowsky, but is necessarily, with reference to the dimorphic character of the
tentacles, referable to the genus Hemiophrya. The number of reproductive gem-
mules produced upon the external surface of the body, as indicated in the figure
given by Haller, exceeds that hitherto recorded of any other species of the genus.

Hemiophrya pusilla, Koch sp.

Body and other structural details closely resembling those of Hemiophrya
Thouleti, but the pedicle two or three times as long as the body. Length
of body 1-300". HAB. — Salt water, on Plumularia setacea.

* "Beitrage zur Kenntniss der Lcemodipodes filiformes," 'Zeitschrift fur Wissenschaftliche
Zoologie,' Bd. xxxiii., 1878.

GENUS PODOCYA THUS. 827

The author has been unable to obtain access to Koch's original description of
this species,* as a type of the genus Podophrya, and is dependent for the brief details
above given to the short reference to it made by Maupas in his account of Hemio-
phrya Thouleti previously described.

GENUS VII. PODOCYATHUS, S. K.
(Greek, pous, foot ; kuathos, cup.)

Animalcules developing tentacles of two orders, some suctorial, and the
remainder simply prehensile, excreting and occupying stalked membranous
sheaths or loricae. Inhabiting salt water.

Podocyathus diadema, S. K. PL. XLVII. FIGS. 1-5.

Lorica conical or cup-shaped, transparent, of very delicate consistence,
obscurely wrinkled or rugose transversely ; pedicle slender, flexuose, two or
three times the length of the lorica ; animalcule subspheroidal, resting upon
a platform-like involution of the front border of the lorica, and in adult
examples usually projecting for about one-half of its total dimensions
beyond this structure ; suctorial tentacles short, few in number, occupying
a central position ; circumjacent prehensile tentacles numerous, extensile to
a length equalling twice the diameter of the body, their substance finely
granulate ; contractile vesicles two in number, basally located ; endoplast
ovate, subcentral. Length of lorica I -600". HAB. — Saltwater.

This as yet single known representative of the newly established genus Podocyathus
may be said to occupy, with relation to the preceding type, Hemiophrya, a position
analogous to that held by the loricate genus Acineta, as compared with Podophrya.
Examples of this species were obtained by the author in some abundance, in the
years 1878 and 1879, at St. Heliers, Jersey, being chiefly found attached to Hydroid
zoophytes and Polyzoa, dredged from a depth of about 10 fathoms. Among these were
zooids in every condition of development, the younger ones, as shown at Fig. 4
of PI. XLVII. , being naked and simply pedicellate, and thus resembling, except
for the character of their tentacles, ordinary Podophrya. It was observed that
even in the fully matured examples the loricse were of very delicate consistence,
mucilaginous rather than membranous, and oscillating perceptibly with every motion
of the water. The transverse wrinkling of the substance of this structure referred
to in the foregoing diagnosis, is evidently produced through the weight of the
animalcule's body resting upon it. In the fact that the zooid reclines upon the
involuted external wall of its lorica, it may be said to possess a commodious
water-cushion rather than a true lorica ; a somewhat similar structural composition
is apparently characteristic of the more indurated membranous loricae of the
two species recently described by M. Fraipont under the title of Acineta divisa
and A. -vorticelloides. Under a magnification of 600 diameters the attenuate
prehensile tentacles of Podocyathus diadema were shown to be finely granulate
exteriorly, the granules, however, not taking a definite form of disposition, or being
developed to the extent that obtains in the homologous appendages of Hemiophrya
gemmipara. It was further observed that these prehensile tentacles were at
frequent intervals flexed towards the body, as in Ephelota coronata ; monads and
other Infusoria being also intercepted and brought by the same action within
reach of the centrally developed suctorial organs, which then speedily seized them,
and appropriated their body-contents after the manner of an ordinary Acineta.

* ' Zwei Acineten auf Plumularia setacea.' Jena, 1876.

828 ORDER TENTACULIFERA-SUCTORIA.

GENUS VIII. SOLENOPHRYA, C. & L.

Animalcules solitary, more or less ovate, secreting a membranous
investing sheath or lorica, which is attached in a sessile manner and without
the intermedium of a pedicle to the chosen object of support ; tentacles
suctorial, capitate, distributed in distinct fascicles.

The representatives of this genus may be said to occupy, with relation to Acineta,
the same position that is held by the similarly sessile but illoricate type Trichophrya,
with reference to the pedicellate genus Podophrya. A single species only has been
so far recorded.

Solenophrya erassa, C. & L. PL. XLVI. FIG. 52.

Lorica oval, depressed, resembling a shallow basin ; body nearly filling
the same, not adherent to it laterally ; tentacles forming four distinct
fascicles ; contractile vesicles multiple ; endoplast indistinct. Diameter of
lorica 1-150".

HAB. — Pond water, on the roots of Lemna minor : Zoological Gardens,
Berlin (C. & L.).

GENUS XI. ACINETA, Ehr.

Animalcules solitary, ovate or elongate, secreting a protective lorica, to
the sides of which they are adherent or within which they may remain
freely suspended; the lorica supported upon a rigid, more or less exten-
sively developed pedicle ; tentacles suctorial, capitate, variously distributed.
Inhabiting salt and fresh water.

The transparent membranous sheaths or loricae, that distinguish the members of
the genus Acineta from those of Podophrya, are held by the author to be homolo-
gous with the protective structures bearing the same title that characterize the several
generic types Cothurnia, Vaginicola, Frria, Bicostzca, Salpingoeca, and others pre-
viously described. While this view of their homology is fully sustained by Maupas,* a
contrary opinion is advocated by Hertwig, Fraipont, and some few other authorities,
who propose to identify this protective element with an ordinary cuticular invest-
ment. That its true character is that of a lifeless excretion, such as a shell or
lorica, is, however, amply demonstrated by the fact that it never takes part in the
subdivision of the body as invariably happens in the case of a living cuticular
investment.

As in the genus Podophrya, the numerous species may, as an aid to their
identification, be conveniently divided into two groups, in accordance with the
fasciculate or irregular disposition of their tentacular appendages.

A. — TENTACLES FASCICULATE.
Acineta livadiana, Meresch. PL. XLVIII. FIG. 12.

Lorica transparent, evenly ovate or urceolate, with its anterior border
truncate, nearly twice as long as broad ; pedicle slender, straight or
flexuose, its height usually corresponding with that of the lorica ; animal-

*" Contribution a 1'Etude des Acinetiens," 'Archives de Zoologie Experimentale," torn, ix.,
1881.

GENUS ACINETA. 829

cule subspheroidal or pyriform, rarely occupying more than the anterior
moiety of the lorica ; tentacles distinctly capitate, forming a single anteriorly
developed sheaf or fascicle, their length when extended equal to that of
the body ; contractile vesicle single, lateral ; endoplast unobserved. Length
of lorica 1—300".

HAB. — Salt water, on various Hydroid zoophytes, seaweeds, and
Polyzoa.

The distribution of this species, figured and described by M. C. Mereschkowsky
in the 'Annals and Magazine of Natural History ' for March 1881, is not, as its title
would imply, limited to the Livadian seaboard. So long since as July 1879 the
author obtained it in abundance attached to zoophytes and Polyzoa collected on the
coasts of Devonshire and Cornwall, and more recently, August 1881, from the
Menai Straits, North Wales, growing in company with Adneta tuberosa and
Ophryodendron sertularia on Sertularia abietina. The symmetrically ovate
contour of the lorica distinguishes it readily from any of the species previously
described.

Acineta tuberosa, Ehr. PL. XLVIII. FIGS. 25-28 AND PL. XLVIIlA. FIG. 7.

Lorica compressed, subtriangular, widest at its distal margin, and
thence tapering gradually towards its point of junction with the pedicle, the
lateral walls continuous over the frontal border, leaving two ovate apertures
at the anterior angles for the extrusion of the tentacles ; pedicle slender,
rectilinear, varying from equal to, to as much as four or five times the
length of the lorica ; body of animalcule mostly attenuate posteriorly,
rarely filling the cavity of the lorica except towards the anterior border*
invariably adherent to it by its posterior extremity, in the region of the
tentacles, and usually along four perpendicular lines extending from the
posterior extremity towards the anterior border, such lines of adhesion
communicating to the body as seen in vertical optic section a distinct
quadrilateral contour; tentacles forming two antero-lateral fascicles, pro-
truding when extended through the corresponding ovate apertures in the
lorica, withdrawn in a sheaf-like manner into the substance of the body by
invagination when retracted ; contractile vesicle single, anteriorly located ;
endoplast elongate-ovate or cord-like, often contorted and branched.
Length of lorica 1-500" to 1-300". HAB. — Salt water.

The synonymy of this species has become somewhat involved in consequence
of its close resemblance to a fresh-water type, originally connected with the same
title by Stein,* and which is here held to be identical with the Acineta lemnarum
of the last-named investigator. The species first distinguished by the title of Acineta
tuberosa by Ehrenberg, is essentially a salt-water form, having a cosmopolitan
distribution, and although but imperfectly figured and described by that authority,
the attention bestowed upon it by several more recent investigators has resulted in
the elucidation of almost every important structural detail. In this connection,
attention may be more especially directed to the elaborate account and illustrations
given of it by M. Julien Fraipont in his memoir upon the Acinetidae of the coast
of Ostend.f As indicated by this authority, the essential difference subsisting

* 'Die Infusionsthiere,' pi. Hi. figs. 48-50, 1854.

t ' Bulletins de 1' Academic Royale des Sciences de Belgique,' 1878.

830 ORDER TENTACULIFERA-SUCTORIA.

between this species and its fresh-water homotype consists of the respective modes
in which they are united to their loricse, and the relative portions of the cavities of
the same that they usually occupy. In the present type adhesion always subsists
between the posterior extremity of the body and the fundus of the loricae, which
does not obtain in A. lemnarum, and while in the last-named species the body more
or less completely fills the cavity of its domicile, in A. tuberosa the posterior region
is usually very attenuate, quadrilateral in shape, and united to the sides of the
lorica at each angle in such a manner that, as seen in transverse optical section,
the cavity of the lorica is as it were divided by four membranous septa into as
many vertical compartments. This structural peculiarity is well shown in the
drawings by M. Fraipont reproduced at PI. XLVIII. Figs. 26 and 28. The last-named
authority adduces as an additional point of distinction between the two forms
under discussion, that while in the fresh-water variety the pedicle is relatively short,
varying from much less to about one and a half times the length of the body, in
the examples of A, tuberosa he examined and figures, the pedicles measured no less
than four or five times such dimensions. The author is, however, disinclined to
accept this distinction as diagnostic, the same length to twice the length of the
body representing the proportions of the pedicle commonly exhibited out of a very
large series of examples derived from different localities as personally examined, and
the same proportions obtaining in the specimens originally figured by Ehrenberg.
Fraipont's types would thus seem to represent indeed a well-marked long-stalked
variety differing in the same manner as the variety A, longipes does from the normal
examples of Acineta mystacina. A much more reliable distinction is apparently
afforded by the relative dimensions of the loricae of A. tuberosa and A. lemnarum, as
specified in the figures quoted in their respective diagnoses, derived in each instance
from examples personally examined.

The character of the endoplast in the present type, not previously recorded, was
clearly demonstrated by Fraipont in specimens treated with picrocarmine, and is
also clearly shown in specimens preserved by the author with osmic acid. Endo-
genous peritrichously ciliated embryos, as observed by Stein of A. lemnarum, are
produced singly in connection with the constriction and separation off of a fragment
of the endoplast. Although collected in the Channel Islands and on the Devonshire
coast, the most abundant development of this species was obtained by the author in
August 1 88 1, growing, in company with Acineta livadiana and Ophryodendron
sertularia, on examples of Sertularia abietina collected in the Menai Straits,
North Wales.

Acineta lemnarum, Stein.

Lorica subtriangular, compressed, widest anteriorly, tapering gradually
towards the posterior extremity, its walls thin and readily adapting them-
selves to the contour of the body ; the body soft and plastic, almost com-
pletely filling the cavity of the lorica, often transversely folded or puckered
posteriorly, but not distinctly adherent to the lorica in this region ; tentacles
finely capitate, forming two antero-lateral fascicles ; pedicle rarely exceed-
ing one and a half times the length of the body, frequently much less,
increasing very slightly in diameter towards its point of junction with the
lorica, slightly curved ; contractile vesicles two in number ; endoplast
ovate ; embryos peritrichous, formed singly in connection with a separation
off of a portion of the endoplast. Length of body 1-600" to 1-500".

HAB. — Fresh water, on Lemna and other aquatic plants.

The author includes under the above title both the Acineta lemnarum and the so-
called A. tuberosa of Stein, figured in PI. III. of his earlier work, ' Die Infusionsthiere,'
published in the year 1854. From the typical marine Acineta tuberosa it differs

GENUS ACINETA. 831

essentially in its smaller dimensions and in the character of the posterior region of
the body, which is never contracted, quadrangular and distinctly adherent to the
lorica, as obtains in that type. In common with many other representatives of the
present genus, A. lemnarum was originally described by Stein as the immature or
" Acinete " condition only of some higher Peritrichous Ciliate Infusorium, the
habitat of this particular type inducing him to regard it as a transitional form of
either Vorticella nebulifera or Epistylis (Opercularia) nutans. Having satisfied him-
self later on that these Acinetae hold a substantial claim for independent recognition,
the title here applied was conferred upon it. The author has recently received
examples of this species from Mr. Thomas Bolton, of Birmingham, growing, in
company with Dendrosoma radians, Acineta grandis, and A. mystacina var. longipes,
on various aquatic plants.

Acineta grandis, S. K. PL. XLVIII. FIG. 24.

Lorica subtriangular, compressed, widest at the anterior border, tapering
gradually towards the posterior extremity, communicating externally by
a cleft-like aperture, which extends throughout the entire length of the
anterior border ; pedicle slender, rectilinear, three or four times the length
of the lorica ; enclosed animalcule ovate or elliptical, usually occupying the
anterior half or an even less considerable area of the cavity of the lorica ;
tentacles distinctly capitate, very numerous, forming two antero-lateral
bundles ; contractile vesicle spherical, subcentral ; endoplast band-like, ren-
dered conspicuously visible only by the action of reagents ; parenchyma
transparent, finely granular. Length of lorica i-ioo" to 1-75".

HAB. — Fresh water, on Anacharis, Nitella, and Potamogeton : Birming-
ham and Stratford Canal.

Examples of this new and handsome species have been remitted to the author in
November of the two consecutive years 1880 and 1881. While at first sight it
would appear to differ but little, except in size, from the respective salt- and fresh-
water forms Acineta tuberosa and A. lemnarum, it is found, on closer inspection, to
yield many distinctive features. The lorica, in the first place, has a much more
simple structure, it being freely open throughout the anterior margin, in place of being
arched over by a continuation of its lateral walls, leaving slit-like apertures only for
the extrusion of the tentacles, as obtains in those two forms. The body of the
animalcule is finally of much less relative size, it usually occupying, as shown in the
accompanying figure, scarcely one-half of the cavity of its protective sheath, and
adhering to it only by its frontal border. The comparatively colossal dimensions of
this species, as compared with its homotype Acineta lemnarum, found growing close
beside it, is well illustrated in the same drawing, and where, at a, an outline of the
more familiar but smaller species has been added for the purpose of comparison.
Although the form and position of the nucleus or endoplast was not readily
detected in living specimens, this structure was rendered distinctly visible in
examples killed with osmic acid and then treated with picrocarmine.

Acineta linguifera, C. & L. PL. XLVI. FIGS. 36-39.

Lorica subtriangular, compressed, tapering posteriorly, developed
anteriorly into two everted, bilaterally even, lip-like expansions, frequently
annulate transversely, each annulation representing a new cycle of growth ;
pedicle very short ; body filling the entire cavity of the lorica, and adherent
to it, projecting in a tongue-like form beyond the anterior margin, bearing

832 ORDER TENTACULIFERA-SUCTORIA.

two antero-lateral fascicles of capitate tentacula ; contractile vesicles
numerous, situated near the anterior border ; endoplast band-like, sinuous.
Length 1-150". HAB. — Fresh water, on aquatic Coleoptera.

This species was originally described by Stein as an Acinete condition of Opercu-
laria berberina, but subsequently received from Claparede and Lachmann the title as
above given. A yet later name proposed by Stein is that of Acineta ligulata. The
embryos of this type, as figured by the last-named authority, see PL XL VI. Fig. 39,
are flattened, and holotrichously ciliate.

Acineta fcetida, Maupas. PL. XLVIII. FIGS. 13-17.

Lorica compressed, subtriangular, the anterior border widest, gradually
diminishing towards the usually obtusely pointed posterior extremity, the
surface of the lorica frequently evenly plicate in an oblique direction, the
anterior border closed in excepting for the presence of a narrow slit-like
opening, supplemented at the two lateral angles by a larger ovate aperture
for the passage of the tentacles ; body almost completely filling the cavity
of the lorica ; the tentacles distinctly capitate, disposed in two antero-
lateral fascicles which protrude through the corresponding apertures in the
lorica ; pedicle short and rudimentary, usually eccentric ; contractile
vesicle single, occupying an antero-lateral position ; endoplast elongate-
ovate, subcentral, with a minute laterally attached endoplastule. Length
of lorica 1-600". HAB. — Salt water, among decaying seaweeds.

The general contour of this species very closely resembles that of the fresh-water
form Acineta linguifera previously described, but may, in addition to its distinct
habitat, be distinguished from that type by the relatively close application of the
front walls of the lorica, these, in that last-named species, being everted to such an
extent as to admit of the protrusion of the body, in addition to the tentacles, beyond
their edges. In the conformation of the internally developed embryos there is like-
wise a most remarkable divergence, for, while in A. linguifera, as observed by Stein,
they are flattened and holotrichously ciliate, in the present type, as figured and
described by E. Maupas, they are elongate-ovate or pyriform, with five obliquely
distinct or continuous spiral ciliate grooves, which communicate to them a singular
helicoidal contour. As many as four represented the common number of these
embryos developed in the brood-cavity of the parent, while in its apparently near
ally, Acineta linguifera, the embryos are usually produced singly. The earlier
phases following upon the attachment of the embryos and their development towards
the adult form in Acineta fcetida, are remarkable from the fact that the lorica in no
way resembles that of the parent, being quite smooth, as broad or broader than long,
and, excepting for the circumstance that the tentacles have a fasciculate arrangement,
might easily be mistaken for that of Acineta emaciata described further on.

Acineta cucullus, C. & L.

Lorica infundibulate or obconical, tapering posteriorly, one side of the
anterior margin deeply emarginate ; pedicle long and slender, even through-
out ; body freely suspended within the lorica, protruding but little from its
orifice, bearing two fascicles of suctorial tubes. Length of lorica i-ioo".

HAB. — Salt water.

The single example upon which Claparede and Lachmann have instituted this
species was captured by them floating in the sea in the neighbourhood of Bergen,

GENUS AC IN ETA. 833

and had evidently become detached from its original basis of support. The external
surface of the lorica was observed to be densely and finely hispid, but they were
unable to determine whether this feature was due to the presence of some foreign
growth or an essential part of the organism. The single specimen examined enclosed
six germs, one of which was seen to escape as a free-swimming pear-shaped embryo,
bearing several circlets of cilia at its more attenuate posterior extremity, and
being devoid of all trace at that time of the tentacula of the adult form.

Acineta notonectae, C. & L. PL. XLVI. FIG. 44.

Lorica subcylindrical, tubular, gradually tapering towards the posterior
extremity, the anterior margin somewhat oblique ; pedicle absent or rudi-
mentary ; body adherent to the lorica, and occupying its entire cavity ;
tentacle distinctly capitate, forming two fascicles at the anterior extremity ;
endoplast oval. Length of lorica 1-150".

HAB. — Fresh water, on Notonecta glauca.

The rudimentary condition of the pedicle in this species, the lorica being mostly
adherent only by its more attenuate posterior extremity, would seem to almost
justify its transfer to the genus Solenophrya.

Acineta compressa, C. & L.

Lorica shortly cup-shaped, as broad as long, exceedingly compressed,
the antero-lateral angles obliquely truncate; pedicle long, slender and
straight, having a short nodular thickening at its point of junction with the
lorica, but below this entirely even ; body nearly rilling the lorica, freely
suspended within the same, bearing two antero-lateral fascicles of capitate
tentacles; contractile vesicle single. Length of lorica 1-275".

HAB. — Salt water : Norwegian coast (C. & L.).

Acineta poculum, Hertwig.

Lorica obconical, or wineglass-shaped, nearly as broad as long, widest
at the antero-border, and tapering gradually towards its point of junction
with the pedicle ; body scarcely occupying the anterior half of the cavity
of the lorica ; tentacles distinctly capitate at their distal terminations,
forming two antero-lateral fascicles, the proximal or intra-parenchymal
terminations of which interlace with one another along the posterior
margin of the body ; pedicle slender, not constricted at its point of junction
with the lorica ; endoplast subspherical. Dimensions unrecorded.

HAB. — Salt water.

The lorica of this type, excepting for the absence of the narrow constriction at
its point of juncture with the pedicle, is apparently closely identical with that of
Acineta patula. The fasciculate distribution of the tentacula, however, affords an
additional means of distinguishing it from that species.

Acineta cothurnia, C. & L.

Lorica wineglass-shaped, rounded posteriorly, the anterior margin
obliquely bevelled, and split into four or five triangular valve-like segments
as in A. mystacina, mounted on a short slender pedicle; body freely sus-

VOL. II. 2 B

834 ORDER TENTACULIFERA-SUCTORIA.

pended within the lorica, occupying about one-half of its cavity, bearing two
antero-lateral fascicles of suckers ; contractile vesicle single ; endoplast
ovate. Length of lorica 1-150". HAB. — Salt water.

This species was originally figured by Stein as the probable Acinete phase of
Cothurnia maritima.

Acineta mystacina, Ehr.
PL. XLVI. FIGS. 40-43 AND 57, AND PL. XLVIII. FIG. 41.

Lorica urceolate, subdivided at the anterior or distal margin into
five or six acuminate, triangular, valve-like lobes, which are bent inwards
and cover the aperture in a lid-like manner; body subspherical, freely
suspended within the lorica, bearing five or six fascicles of capitate
tentacula, which are extended through the fissure-like clefts between the
valves of the lorica ; contractile vesicle single ; endoplast rounded or
ovate ; pedicle varying in length from a less magnitude to four or five times
the length of the lorica, formed ;out of a hollow, attenuate, posterior
extension of the walls of the lorica. Length of lorica 1-120".

HAB. — Fresh water, on Lemncs and other aquatic plants.

This form was originally described and figured by Stein as the Acinete phase of
Vaginicola crystallina. Claparede and Lachmann observed this species multiply by
the process of transverse fission, and ascertained that the separated product was, at
the time of its release, densely clothed with fine cilia, in addition to bearing the cha-
racteristic suctorial tentacles. In accordance with the observations of Stein, the
propagation of this species may be accomplished in a yet more abundant manner,
through the development of hypotrichously ciliate embryos, which are passed out of
the body and deposited singly within pocket-like diverticula of the parental mem-
brane ; these being extruded between the valves of the lorica, remain for some little
time attached apparently to the outer wall of this structure, as shown at PI. XLVI.
Figs. 40 and 43. In some instances no less than four or five of these embryonic
bodies are represented by Stein as attached to the distal border of a single zooid.
As recognized by the authority last quoted, the length of the hollow pedicle in this
type with relation to that of the lorica it supports varies very considerably, being
in some instances quite rudimentary or represented by a short conical elongation
only of the substance of the lorica, or in opposite cases equalling or surpassing the
altitude of the lorica. Mereschkowsky * has figured and described a variety of this
type in which the pedicle is very much more attenuate, being equal in length to from
five to seven times that of the lorica. Examples of this variety, for which
Mereschkowsky has proposed the title of Acineta mystacina var. longipes, have been
quite recently, October and November 1881, received by the author from two
different localities, namely, through Mr. J. Thomas from the neighbourhood of
Epping, and through Mr. Thomas Bolton from the Birmingham district. In the
last-named instance the animalcules were very abundantly developed, in company
with Acineta grandis, A. lemnarum, and Dendrosoma radians, on the leaves of
Nitella, Many of these were observed undergoing the process of transverse fission
in the manner described by Claparede and Lachmann. Some interesting drawings
and very abundant colonies of the more typical short-stalked variety of this species
were remitted to the author by Mr. F. W. Phillips in August 1881. Among the new
data elicited by Mr. Phillips may be mentioned the fact that the tentacles, when
contracted, exhibit, under high magnification, a distinct zigzag or spiral aspect, such
appearance being due to the presence of a delicate external spiral fibrilla analogous

Protozoen des Nordlichen Russland," ' Archiv fiir Mikr. Anatomic,' Bd. xvi., 1878.

GENUS AC I NET A. 835

to that more conspicuously developed in Podophrya elongata, as also that the
tentacles, when extended, are capable of flexure in various directions. Mr. Phillips
has attested in his communication to having on one occasion observed a brood of
flagellate organisms escape from an otherwise uninhabited lorica. At first
sight these were supposed to have had some connection with the developmental
phenomena of the species, but is interpreted by the author as representing a case
only of the intrusion and reproduction of a Flagelliferous form within the vacated
domicile of the Acinetan.

Acineta Jolyi, Maupas. PL. XLVIII. FIGS. 34 AND 35.

Lorica exceedingly compressed, irregularly quadrate, about one and a
quarter times as long as broad, the lowermost angle, which is united with
the pedicle, being the most attenuate ; the anterior and two lateral angles
abruptly truncate, leaving ovate apertures for the extrusion of the tentacles ;
pedicle slender, rectilinear, somewhat longer than the lorica ; contained
animalcule occupying the greater portion of the cavity of the lorica ;
tentacles forming three — one anterior median and two lateral — fascicles
corresponding in position with the apertures in the lorica, their bases
apparently produced into the central region of the body ; contractile vesicle
subcentral, anteriorly located ; endoplast discoidal, occupying a similar
position towards the posterior region of the body. Length of lorica
1-120". HAB. — Salt water, Algiers.

This species, on account of its greatly compressed contour and corresponding
tenuity as seen in profile, is exceedingly transparent. With respect to its possession of
three tentacular fascicles, it differs distinctly from all species of the genus previously
described, while Podophrya pyrum is the only type among the illoricate forms in
which an analogous plan of distribution obtains. According to M. Maupas, its dis-
coverer, the contractile vesicle is remarkable for the length of time that intervenes
between its contractions, as much or more than an hour not unfrequently representing
this interval. As in many allied species, this vesicle is formed by the flowing
together of numerous smaller lacunae. The nucleus or endoplast in examples
treated with a one per cent, solution of osmic acid was found to enclose numerous
transparent vacuoles having a central refringent corpuscle, while in many instances
there was attached to the lateral periphery of this structure a minute spherical body,
which probably represents an endoplastule.

B. — TENTACLES IRREGULARLY DISTRIBUTED.
Acineta patula, C. & L. PL. XLVI. FIGS. 45-47.

Lorica cup-shaped or infundibulate, tapering posteriorly, widest at its
anterior margin, seated on a long rectilinear stem with a narrow constriction
at the point of junction between the two ; body equal in height to the
lorica, ovate or spherical, its lower extremity only resting within the lorica
and not adherent to it ; tentacles distinctly capitate, very long and slender,
protruded from every portion of the periphery. Height of lorica without
the stalk 1-85" to 1-50". HAB. — Salt water, on Algae.

The aspect of this elegant animalcule, seated in its long-stalked cup-like lorica,
and with the tentacula withdrawn, is fancifully suggestive of the children's toy dis-
tinguished by the familiar title of " cup and ball." Both conjugation and the pro-
duction by the individual animalcules of a single embryo, apparently ciliated

2 B 2

836 ORDER TENTACULIFERA-SUCTORIA.

throughout, have been observed by Claparede and Lachmann in association with
this species.

Acineta Saifulae, Meresch. PL. XLVIII. FIG. 29.

Lorica elongate-conical, two or three times as long as broad, widest
anteriorly and gradually tapering towards its narrowest posterior region,
finely striate or annulate transversely, the anterior -half of the lorica
separated from the posterior one by a membranous septum or platform, upon
which the body of the animalcule reclines ; pedicle slender, about twice the
length of the lorica, straight or slightly arcuate, hollow and continuous with
the walls of the lorica ; animalcule elongate-ovate, projecting for a distance
of about one-half of its entire length beyond the aperture of the lorica ;
tentacles slender, distributed throughout the exposed periphery ; endoplasm
granular, pale yellow ; endoplast spherical, subcentral ; contractile vesicle
unobserved. Length of lorica 1-400".

HAB. — Salt water : White Sea (Mereschkowsky).

This species is described by Mereschkowsky * from spirit-preserved examples
only. While in the contour of its lorica it to some extent resembles the Acineta divisa
of Fraipont, it may be readily distinguished from that form by the distinct annula-
tion of the surface of the lorica, and by the continuity of its cavity throughout the
substance of the pedicle. In this last-named respect it stands alone among the
known salt-water representatives of the genus, while Acineta mystacina, and more
particularly the variety A. longipes, is the only fresh-water form that is similarly
characterized.

Acineta divisa, Fraipont. PL. XLVIII. FIGS. 8-n.

Lorica symmetrically conical or wineglass-shaped, widest and some-
what expanded at the anterior border, tapering thence towards the
posterior extremity, divided subcentrally by a delicate transverse mem-
branous septum upon which the body of the animalcule reclines ; pedicle
slender, five or six times the length of the lorica, not constricted at its
point of junction with it; animalcule subspherical or ovate, elevated above
the aperture of the lorica, capable of considerable extension ; tentacles
numerous, distinctly capitate, developed equally over the anterior peri-
pheral border ; parenchyma pale yellow, finely granular ; endoplast ovate or
nodular, subcentral. Length of lorica 1-600". HAB. — Salt water.

Excepting for its smaller size, the more solid mode of junction of the lorica with
its pedicle, and the presence of an internal membranous septum upon which the
animalcule rests, this species very closely resembles the Acineta patula of Claparede
and Lachmann previously described. According to its discoverer, M. Fraipont, j this
species exhibits remarkable reproductive phenomena. Small pyriform capsular
diverticula are developed from the anterior surface of the animalcule's body — not
accompanied by an outgrowth of the parent endoplast as in Hemiophrya gemmipara
— within which are independently generated minute peritrichously ciliated embryos,
which effect their exit through an operculum-like modification of the distal wall of
their respective capsules. A somewhat analogous reproductive process has been
shown by Stein to obtain in Acineta mystaclna, though in that type it would appear

* ' Ann. Nat. Hist.,' March 1881.

f " Acinetiens de la Cote d'Ostende," ' Bull. Acad. Bruxelles/ 1879.

GENUS A CINE TA. 837

that ciliated embryos are passed from the body of the parent into pocket-shaped
extensions of the cuticular membrane. Somewhat similar reproductive phenomena
have been likewise recently observed by the author in connection with Dendrosoma
radians.

Acineta crenata, Fraipont. PL. XLVIII. FIGS. 32, 33.

Lorica transparent, elongate-conical, about twice as long as broad, its
external surface finely crenulate and irregularly striate transversely ; pedicle
slender, about twice the length of the lorica ; enclosed animalcule ovate or
pyriform, occupying the anterior half of the lorica, and projecting to some
distance beyond its anterior border ; tentacles about twenty-six in number,
distributed over the anterior surface of the periphery ; usually one large
contractile vesicle developed towards the wider posterior region of the body,
and one smaller towards the narrower posterior region ; endoplast sub-
spherical or irregular in shape. Length of lorica 1-500".

HAB. — Salt water, on the zoophyte Clytia volubilis.

Acineta vorticelloides, Fraipont. PL. XLVIII. FIG. 42.

Lorica rudimentary, consisting of a small cup-shaped expansion only of
the distal extremity of the supporting pedicle ; pedicle slender, four or five
times the length of the body; body subspherical ; tentacles developed
throughout the exposed peripheral surface, widest at their base, extensile to
a length equal to the diameter of the body ; parenchyma dirty yellow, often
enclosing oleaginous corpuscles ; contractile vesicle single, of large size ;
endoplast ovate, posteriorly located, rendered visible only by the action of
reagents, frequently enclosing minute granular endoplastules. Length of
body 1-500". HAB. — Salt water, on the zoophyte Clytia volubilis.

This species is of special interest on account of the rudimentary condition of the
lorica, which is little more than a shallow cup-shaped expansion of the substance of
the pedicle. In this connection Acineta vorticelloides may be regarded as an
annectant type between the two genera Acineta and Podophrya.

Acineta pusilla, Maupas.

Lorica minute, compressed, subquadrate or lozenge-shaped as seen in
front view, having the anterior and posterior borders evenly rounded, and
the two lateral angles acuminate, the width somewhat exceeding the
greatest depth ; pedicle slender, rectilinear, slightly exceeding the lorica in
length ; enclosed animalcule almost completely filling the cavity of the
lorica ; tentacles short, four or five in number, distributed irregularly along
the frontal border ; contractile vesicle unobserved ; endoplast ovate, situated
towards the basal region of the body. Length of lorica 1-1800".

HAB. — Salt water, on Bryozoa dredged off the port of Algiers
(Maupas).

Acineta emaciata, Maupas. PL. XLVIII. FIG. 18.
Lorica compressed, subquadrate, often wider than broad, the anterior
median angle being rounded so as to form an almost complete semi-

838 ORDER TENTACULIFERA-SUCTORIA.

circle, the two lateral and a median posterior angle being left intact, a
narrow fissure-like cleft slightly widened at its two extremities, extending
along the front border between the two lateral angles ; pedicle slender,
rectilinear, very short, not exceeding one-half of the diameter of the lorica ;
body of animalcule rarely occupying more than the anterior moiety of the
cavity of the lorica, often limited to a narrow lunate or fusiform granular band
adherent to its upper wall ; tentacles distinctly capitate, very short, varying
from two or three to as many as fifteen in number, distributed irregularly
along the frontal border, and protruding from the fissure-like cleft of the
lorica ; contractile vesicle single ; endoplast spheroidal or ovate. Diameter
of lorica 1-350". HAB. — Saltwater: Algiers.

Acineta stellata, S. K. PL. XLVI. FIGS. 32-35.

Lorica subpyriform, its cavity continued inferiorly into a short, gradually
tapering, hollow, stalk-like attachment, its lateral walls at the points of
exit of the tentacula produced outwards as fine radiating tubuli ; contained
body subglobose or stellate, the tentacles capitate, their length when
extended exceeding the diameter of the body, varying in number from six
or seven to as many as twelve, radiating from all parts of the periphery,
and perforating the substance of the lorica ; contractile vesicle, single ;
endoplast spheroidal, subcentral. Height of entire lorica 1-1500" ; diameter
of body 1-3000". HAB. — Pond water, on Conferva.

This species was obtained by the author, in August 1871, attached in con-
siderable quantities to Confervas taken from a pond at Stoke Newington, London.
Its excessively minute size readily distinguishes it from all the forms hitherto
described, while, at the same time, the general contour, with its characteristic
attachment, consisting rather of a tapering prolongation of the lorica than of a
distinct pedicle, corresponds to some extent with that of the short-stalked variety of
Acineta mystacina, delineated at Fig. 41 of the same Plate. The characters afforded
by the disposition of the tentacles and their relationship with the investing lorica
are entirely at variance with that form or any previously recorded type. As intimated
in the foregoing diagnosis, these tentacula radiate in all directions, and appear to as
it were perforate the wall of the lorica rather than to issue from any definite
apertures or fissures in its substance. Such perforation of the walls of the lorica must
evidently take place during its newly formed, mucilaginous condition, it being only
at this time sufficiently soft to permit the tentacles to push before and carry out with
them slender tubular prolongations of its substance. That these tubular prolonga-
tions of the walls of the lorica have a substantial existence is best demonstrated by
an examination of the animalcule in its encysted condition. In this state, notwith-
standing that the body is shrunk up into a compact globular form within the central
cavity, tentacule-like processes are still to be seen radiating from the walls of the
lorica ; these, however, have no capitate extremities, and are found, on closer
investigation, to be entirely disconnected from the central encysted body, and to
be merely slender, hollow extensions of the lorica-wall, as shown at PI. XLVI.
Figs. 33 and 34. It was not unfrequently observed that the body of the animal-
cule inside these characteristic encystments, as delineated in the first of the two
figures quoted, had divided into two by transverse cleavage. Sometimes the pedicle-
like portion is so short and inconspicuous as to present the character only of the
ordinary tubular prolongations of the lorica associated with an extruded tentaculum,
and with which this structure, as demonstrated in the case of Podophrya mollis, is
without doubt originally homologous. Not unfrequently, again, the lorica was

GENUS DENDROCOMETES. 839

found moored to its fulcrum of support by two much smaller basal extensions, in
place of the more ordinary single and larger one. An example of this modification
is given at Fig. 34. Minute spherical freely floating Sph(zrophrya-\iik.Q organisms,
PI. XLVI. Fig. 35, were frequently found in the neighbourhood of these animalcules,
and represented apparently the earlier conditions of this species.

Acineta dibdalteria, Parona.

Lorica wineglass-shaped ; peduncle slender, rectilinear, about half the
length of the lorica ; tentacles two in number only, placed opposite one
another, both suctorial and prehensile, movable in all directions ; endoplasm
granular, more transparent at the periphery ; contractile vesicle single, of
large size ; endoplast horseshoe-shaped. Length of lorica 1-500".

HAB. — Salt water.

This species is reported by Dr. C. Parona* from the Gulf of Genoa, its essen-
tially distinctive features consisting of the small number of the tentacles, their
great mobility, and adaptation to distinct functions. With reference to their mobile
properties, it may be mentioned that a similar character is shared by various other
forms, among which Acineta mystacina and Podophrya elongata, as examined by the
author, may be specially cited. In connection with the first-named of these two
species, a similar phenomenon has likewise been recently observed by Mr. F. W.
Phillips, of Hertford.

GENUS X. DENDROCOMETES, Stein.

Animalcules solitary, sessile, discoidal or subspherical ; the surface of
integument indurated ; tentacles slightly flexible, but not contractile, more
or less branched and finely perforate at their extremities. Endoplast and
contractile vesicle conspicuous ; increasing by internal gemmation.

Dendrocometes paradoxus, Stein. PL. XLVIIlA. FIGS. 8-12.

Body plano-convex or discoidal ; tentacles springing from the peri-
pheral margin, equal to or slightly exceeding the diameter of the body in
length, rarely more than five in number, usually branched in a bi-tripartite
manner; contractile vesicle single; endoplast subtriangular. Diameter
of body 1-300".

HAB. — Fresh water, on Gammarus pulex. Embryos hypotrichously
ciliate.

This singular organism was originally supposed by Stein to represent an Acineti-
form condition of Spirochona gemmipara ; the occurrence of the two as parasites
or commensals of the same host, together with the circumstance that the external
gemmae of the Vorticellidan, in the earliest stages of their development, bear a con-
siderable resemblance to the internally developed ciliate embryos of Dendrocometes^
affording him at that time considerable foundation for this opinion. Although
the independent nature of this type is now fully substantiated, its relegation to
this group of the Tentaculiform Infusoria has been presumably tentative and
provisional, no evidence having hitherto been adduced as to the use made by
the animalcule of its constantly extended and almost rigid tentacles, or as to what
manner, if any, they are subservient to the purposes of food-inception. Through,

* 'Arch. Sci. Phys. et Nat.,' 1881, also 'Trans. Royal Mic. Soc.,' June 1881.

840 ORDER TENTACULIFERA-SUCTORIA.

however, the investigations of Wrzesniowski,* the mystery up to the present time
associated with this very remarkable organism has been satisfactorily dissipated,
and Dendrocometes is demonstrated to share all the essential characteristics of the
order to which it has been hitherto but provisionally relegated. While in their
more ordinary condition the distal terminations of the characteristic antler-like
appendages of this type present a simply conical and pointed aspect, Wrzesniowski
shows that their terminations are capable of foreshortening and expansion, and that
under such conditions they exhibit with a magnifying power of 1200 diameters
minute tubular axial canals, forming a channel of communication from the
exterior down the main branches into the body of the animalcule. It was further
proved by this investigator that these distal terminations of the branchlets possess
the faculty of closing upon and holding other Infusoria, the contents of which are
then sucked out and transferred to the parenchyma of its own body, after the same
manner as an ordinary Acineta incepts the life-juices of its prey through the one or
more suctorial tentacles wherewith it holds it captive. Adopting a somewhat fanciful
simile, the phenomena attending this seizure and inception of food by Dendrocometes,
as represented at PI. XLVIIlA. Figs. 8a and 9, might be appropriately compared
to that of a man, his normal alimentary functions being suspended, endowed with
the capacity of grasping an orange with his hand, and transferring its juices to his
own body through perforations in the tips of his fingers.

The embryos, as first figured and described by Stein, and more recently investi-
gated with great success by Biitschli, f present a hypotrichous aspect, corre-
sponding closely with those of Podophrya gemmipara and Ophryodendron abietinum,
being ovate with a flattened ventral and convex dorsal surface, the peripheral
margin of the former bearing a border of cilia, and having a curved excavated
central area of somewhat variable form. These embryos, which are matured singly
within the parent, occupy a very considerable portion of its body-cavity, and, without
some special provision for their release, their liberation would seem impossible.
As shown, however, by the authority last quoted, a fissure-like aperture makes its
appearance in the indurated cuticle of the parent zooid when the embryo is ripe,
and through this it is gradually expressed into the outer water. A portion of the
endoplast of the parent animalcule, it is also shown by Biitschli, becomes separated
off and incorporated into the body of the ciliated embryo, while at the time of its
liberation it possesses also a conspicuous contractile vesicle. This latter structure
in the adult zooid is demonstrated by Biitschli to communicate externally through
the medium of a minute persistent tubular aperture.

Professor E. Ray Lankester has recently informed the author that this interesting
species occurs abundantly on Gammarus pulex in the neighbourhood of Hampstead.

GENUS XI. DENDROSOMA, Ehrenberg.

Animalcules intimately fused with one another, and forming an erect
branching colony-stock or zoocaulon, or several such erect zoocaula united
basally by a creeping adherent stolon ; the terminations of the erect
branches bearing numerous capitate suctorial tentacles similar to those of
the ordinary Acinetidae ; the compound colony-stock increasing in size by the
extension of the adherent stolon and development from it of new zoocaula,
and by the repeated fission and outgrowth of the terminal branches ; local
distribution effected by the production of endogenous ciliated embryos, and
by exogenous gemmation ; contractile vesicles and endoplast distinctly
developed. Inhabiting fresh water.

* ' Zeitschrift fur Wissenschaftliche Zoologie,' Bd. xxix. p. 270. 1877.
f Ibid., Bd. xxviii. p. 49, 1877.

GENUS DENDROSOMA. 841

The type of the genus. Dendrosoma radians, may be said to represent one of the
most remarkable forms described in this treatise. Not only does it occupy an
isolated position as the only known compound member of the Tentaculiferous
class, but it is furthermore the only example throughout the entire Infusorial series
in which the individuality of the component zooids is so far obliterated that the
entire colony-stock maybe justly described as a homogeneous multicellular organism or
" syncytium." In many of the Flagellata and Ciliata previously described — including
notably among the latter the compound Vorticellidae such as Carchesium and Epistylis
— somewhat analogous colonial aggregates occur ; but in all of these the individual
zooids are distinctly isolated from each other, the genus Zoothamnium affording the
only instance in which they are more intimately united through the interposition of
a living tissue, as represented by the axial muscle-like element or fibrilla of the
branching pedicle. In Dendrosoma, however, not only are the component zooids
indistinguishably fused with each other, but a common nutritive fluid circulates
throughout the creeping rhizome and ramifying branches. An adult colony-stock of
Dendrosoma radians, such as is represented at PL XLVII. Fig. 17, presents, indeed,
an extraordinary resemblance to the colony-stock of some Hydroid zoophyte, such as
Coryne or Cordylophora ; and, notwithstanding the fact that the component zooids of
Dtndrosoma must be regarded as potentially unicellular, which precludes a direct
homological comparison with such higher metazoic types, the points of agreement
that can be cited are most remarkable. In both cases we find in the fully developed
organism a basal adherent stolon or rhizome, which gives origin to a greater or less
number of erect diversely ramifying stems, the hydrocaulus or hydrosoma of the
zoophyte and zoocaulon or zoocaula of the Acinetan, these developing in either case
at their extremities tentaculiferous zooids, the tentacles, it is worthy of remark, in
Coryne further resembling those of Dendrosoma in being capitate. It is found that
the analogy suggested extends even beyond these more obvious superficial cha-
racters. The processes and products of the reproductive phenomena singularly
coincide with each other, but in the case of Dendrosoma are, as might be anticipated,
much more generalized. The Hydroidea, as is well known, produce embryos of
two kinds, these being either simply ciliated larvae or Planula, or medusiform
gonozooids, which are, strictly speaking, natatory modifications only of the ordinary
alimentary zooids or polypites. In but few, if any, members of this class are these
two descriptions of embryos developed in the same species. In Dendrosoma radians,
however, as hereafter shown, reproductive bodies analogous to both of these struc-
tural types may be produced by the same colony-stock, free-swimming ciliated
germs being liberated from the more massive basal region of the erect trunks, while
more minute tentaculiferous embryos, developed by gemmation in membranous
capsules, corresponding with the gonothecae of the Hydroid polype, are produced
towards the distal extremities of the branches, in close vicinity to the alimentary
acinetiform zooids. All these points being considered, added to the evidence in a
similar direction previously submitted, see vol. i. pp. 104 and 105, it is difficult to
arrive at a conclusion otherwise than that the Acinetidae, more particularly as typified
by Dendrosoma, represent the archetypes or direct lineal ancestors of the Hydroidea.
If Mr. Levick's observations concerning the development of spermatic elements in
certain colony-stocks and ova in others, as hereafter described, should be confirmed,
thus demonstrating the existence of true generative reproduction on a dioecious
plan, the arguments here brought forward in favour of the advanced affinities of
Dendrosoma will be immeasurably strengthened.

Dendrosoma radians, Ehr. PL. XLVII. FIGS. 16-22.

Stolon depressed, repent, giving origin to a greater or less number
of erect tentaculiferous zoocaula ; zoocaula simple or variously ramified,
thickest at the base, tapering evenly towards their distal terminations, the
secondary branchlets or ramuscules produced by longitudinal fission, divari-

842 ORDER TENTACULIFERA-SUCTORIA.

eating mostly at angles of from 30 to 50 degrees from the main stem, but not
unfrequently decussating at right angles or even reflected backwards, their
extreme ends usually slightly dilated ; tentacles distinctly capitate, highly
extensile, developed in a sheaf-like or fasciculate manner from the slightly
dilated terminations of the ramuscules ; contractile vesicles numerous,
spherical, irregularly distributed throughout the main stem and secondary
branches ; endoplast ribbon-like, ramifying and much contorted in the stolon
and basal portions of the main stem, continued as a simple band into the
distal region and secondary branchlets ; endogenous, hypotrichously ciliated
embryos of relatively large size developed in nodular enlargements of the
main stem or primary branchlets ; more minute, pyriform, tentaculiferous
germs produced by gemmation towards the terminations of the ultimate
branchlets. Height of adult colony-stock 1-25" to i-io"; average diameter
of tentaculiferous distal terminations 1-500".

HAB. — River and pond water, on Anacharis, Myriophyllum, and other
aquatic plants.

Dendrosoma radians was originally described by Ehrenberg * as a compound
species of Actinophrys ; Perty, Dujardin, and other contemporary investigators
placed it on Ehrenberg's authority in the same category, while Pritchard, in his
'History of the Infusoria,' p. 562, 1861, suggested the probability of its being
more nearly allied to Anthophysa. Claparede and Lachmann, who were the first to
carefully re-examine this organism, at once recognized its Acinetan affinities, and
described it at length, with an accompanying highly characteristic illustration, in
their well-known ' Etudes sur les Infusoires,' published in the ' Memoires de
1'Institut Genevois,' between the years 1858 and 1860. These investigators, never-
theless, failed to recognize, or rather misinterpreted, certain of the more important
structural features of this species, and were altogether unacquainted with any
phenomena of propagation apart from those connected with the increase in dimen-
sions of the parent colony by repeated fission of the terminal branches, or by
the outgrowth of the creeping stolon or main trunk. The chief error committed
by these authorities consists of the fact that they figured and described the con-
tractile vesicle as a long canal-like lacuna, extending throughout the substance of
the main trunk, with offshoots to the secondary branches, and having spherical
dilatations at irregular intervals. The nucleus or endoplast was at the same time
entirely overlooked, or its outline apparently mistaken for that of the so-called
contractile vesicle. Both of these last two structures, while not referred to in
Ehrenberg's original description, are distinctly indicated in his drawings, then
mislaid but subsequently published in the ' Abhandlung der Berliner Akademie ' for
the year 1862. Stein, who was also personally acquainted with this form, fully
recognized its true position, and rightly interpreted its structural characters in a
brief reference made to it in the first volume of ' Organismus ' (p. 90, 1859), but adds
nothing with reference to the phenomena of reproduction. The honour of placing
on record the first authentic account of the propagation of Dendrosoma radians by
any other method than that of the outgrowth of the parent stock belongs to
Mr. J. Levick, of Birmingham. This microscopist has published, in the ' Transac-
tions of the Birmingham Natural History Society' for the year 1880, an account,
with accompanying illustrations, of a prolonged examination of this species, and in
the course of which he observed the release of ciliated embryos from the parent-
stock, and their attachment and development of tentaculate appendages. Mr. Levick
further describes what he interprets to be the propagation of this species by a
distinct genetic process, capsular bodies being produced as outgrowths of the stem

* ' Die Infusionsthierchen,' 1838.

GENUS DENDROSOMA. 843

and branches, to which he assigns the distinct characters of ovaries and testes, and
in connection with which he maintains he observed the development respectively of
ova and spermatic elements. His statement with reference to this phenomenon is of
such importance that it is herewith reproduced. After describing the ciliated
embryos he thus proceeds : — " The same group of organisms which had now been
under frequent and sometimes protracted observation for eight weeks, furnished me
with two specimens, showing what were evidently true sperm and germ elements,
these features occurring in two separate individuals in close proximity to each other.
They bore so much resemblance to the testis and ovary of the Hydra that I felt no
doubt whatever of their function from the first, though I had never seen the
phenomenon before in Dendrosoma, and was not aware of its having been noted in
this or any other form of the Acinetina. After a little patient watching, I was
rewarded by seeing the spermatozoa, not only in active motion within the sperm
cell, but also escaping freely into the surrounding water. At the same time the
ovary on the other individual, which at first showed only a slight circular mark, had
now a decided opening ; though I could not positively trace the contact of the
fertilizing agents with the germ, the process was so conclusive as to leave no doubt
of its meaning in my mind." Mr. Levick further records the observation of egg-like
bodies, apparently derived through the union of these elements, they having some
resemblance to minute statoblasts of a fresh-water Polyzoon and probably remaining
in a like manner in a state of rest through the winter.

Should Mr. Levick's observations concerning the reproduction of Dendrosoma
radians by a distinct genetic process be confirmed by further investigation he will
undoubtedly have made one of the most important discoveries yet recorded in
connection with the Infusorial series. In none of these so far is the development of
distinct sexual elements and the production of embryos through the concourse of
these elements known to occur, and should such phenomena actually take place, it
affords more substantial evidence than any yet adduced with reference to the
relatively high organization of the Acinetidae advocated in this treatise. Concerning
the reproduction of Dendrosoma by two independent germinal processes, the author
is in a position to entirely confirm the observations of Mr. Levick, though he cannot
proceed so far with relation to its accredited development of distinct sexual elements.
On many occasions within the past few years the author has had an opportunity of
examining examples of the type now under discussion, but it is only in connection
with specimens remitted from Birmingham by Mr. Thomas Bolton so recently as
December 1881, that the phenomena referred to have been observed. Unfortunately,
not being aware at the time of the nature of Mr. Levick's evidence, the opportunity
was lost for effecting, in connection with living specimens, an investigation of that
specially important point to which attention has just been drawn, though, on the
other hand, the results obtained have the advantage of being arrived at independently,
while in addition, with the use of reagents, examples, in which all of the more
important features as hereafter described, have been permanently preserved.

The example of Dendrosoma radians delineated at PI. XLVII. Fig. 17 has
been specially selected by the author from among the specimens recently remitted
by Mr. Thomas Bolton, on account not only of its containing both of the two sorts of
reproductive bodies produced, but also as representing the largest and most extensive
colony-stock of which an account has so far been published. The one of very con-
siderable size originally figured by Claparede and Lachmann, and hitherto acknow-
ledged to be the largest recorded example, exhibited a total altitude of as much as one
millimetre (i-25th of an English inch). In the example here delineated the height of
the main trunk measured no less than i-ioth of an inch, with a lateral extension
of equal measurement, and was distinctly visible to the unaided vision. The
creeping stolon, not figured or referred to in Mr. Levick's description, and not
observable in young colony-stocks, was very extensively developed. It had a more
depressed form than is indicated in Claparede and Lachmann's figure, and distinctly
anastomosed, leaving a central perforation, wherever it came in contact with a neigh-
bouring outgrowth of the same element. By treating examples with osmic acid and

844 ORDER TENTACULIFERA-SUCTORIA.

subsequently with picrocarmine the component protoplasm of the stolon was dis-
tinctly coloured, and the limits of its extension upon the surface of the plant to
which it was attached distinctly denned. By the same process it was also shown
that the nucleus or endoplast was largely developed in this region, assuming a more
or less convoluted or ramifying contour, the same modification of this element being
noticeable in the larger of the erect trunks. Of such erect branches there were in the
example under special notice no less than nine, all of them giving off a greater or
less number of secondary branchlets, the central one being specially conspicuous for
its thickness, and yet more extensive subdivision. The terminations of all the ultimate
ramifications were, for the most part, alike, in so far as they bore a sheaf or coronet
of capitate, highly extensile tentacles. This uniformity did not, however, extend to the
composition of the axial regions of the main trunks or branches. Certain of these,
more especially towards the left-hand region of the colony-stock delineated in the
accompanying illustration, exhibited an altogether abnormal zigzag contour, the
knee-shaped joints produced by this form of growth being much swollen or cyst-
like, and enclosing a distinctly differentiated ovate or subspheroidal body. It was
at first supposed that these structures represented either a diseased condition or some
parasitic growth. After prolonged examination, the enclosed bodies were, however,
observed to make their escape, through rupture of the parent, as single large hypo-
trichously ciliated embryos, whose reattachment and development to the parent
form was subsequently followed. That these ciliated embryos were produced, as in
many other Acinetidse, by a separating off of a fragment of the parental endoplast
accompanied by a circumferential portion of its body-substance, was clearly traced
in the less developed examples.

In addition to the nodular excrescences which gave birth to the ciliated embryos,
developed mostly towards the basal region of the main trunks, the distal extremities
of the ultimate branchlets of the same colony-stock bore in many instances one or
two, or it might be a considerable number of laterally attached subspherical or pyri-
form capsular bodies, having clearly also a reproductive function. These, as com-
pared with the bodies previously described, were relatively of small size, and coin-
cide apparently with the structures to which Mr. Levick has assigned properties
identical with those of a testis and ovarium. As examined independently, without
being cognizant at the time of Mr. Levick's interpretation, as also subsequently, in
connection with preserved examples, the author has not been able to arrive at a like
result. On the contrary, it would seem to him that these bodies agree as nearly as
possible with the exogenously produced germs described by Stein of Arineta
mystacina. In the majority of instances these in a like manner possessed a distinct
membranous or capsular investment, derived from the pushing outwards and subse-
quent hardening of the parent cuticle. Within this capsule the protoplasmic matter
separated from the parent had usually contracted into subspheroidal form, showing
distinctly a large central nucleus, and in some instances a pulsating contractile
vesicle. The front walls of the capsule were evidently of greater tenuity than the
remaining area, being often lacerated and broken, leaving the germ freely exposed
to the surrounding water, and forming the point of least resistance at which it was
normally set free, as evidenced by the fact that many of these capsules remained
in an empty state attached to the parent stock, a ragged perforation at their distal
end indicating the point of exit of the previously contained body. Although in no
instance so far has the author been able to detect the presence of cilia in any form
upon these encapsuled germs, it was in several instances observed that short capitate
tentacles were developed at various parts of the periphery, as shown at PI. XLVII.
Fig. 1 8, so that on being liberated from the parent stock they would be scarcely
distinguishable from minute Sphcerophryce. Similar short capitate tentacles, it was
likewise noticed, were frequently developed from the bud-like processes of the
parent stem previous to their isolation from it by constriction and the formation of
a distinct capsule.

While the further development of the more minute, encapsuled, subterminally
developed embryos has not so far been traced, the numerous phases of the larger

GENUS DENDROSOMA. 845

ciliated germs developed from the substance of the erect trunks were abundantly
observed. These in the main agree substantially with what has been recorded by
Mr. Levick, though in some few details the author is in a position to supply new
data. Thus with the aid of picrocarmine it was demonstrated that the endoplast or
nucleus, not recognized in either the adult or embryonic state by Mr. Levick, is
already well developed and more or less ramified by the time the embryo has
developed its first erect tentaculiferous ramuscule, and moreover that short capitate
tentacles are produced irregularly from all parts of the free periphery prior to the
appearance of the early bud-like outgrowth of this stem, and are retained for a
considerable interval after its appearance. These several points are fully illustrated
in Figs. 19-22 of the Plate already quoted. It is there shown, see Fig. 22, that
one branch of the endoplast is developed towards and finally ascends the initial
stem, while the other branches follow the various directions of growth taken by the
adherent stolon. As indicated in the same figures, a number of contractile vesicles
are developed not only in the initially fixed but also in the free-swimming condition
of the ciliated embryos.

Attention may be suitably directed at this point to the very considerable resem-
blance that subsists between that early developmental phase of Dendrosoma radians,
in which it consists simply of a flattened adherent body out of which is produced a
single erect stem with its apical sheaf of tentacles, and the normal condition of the
proboscidiform zooids of an Ophryodendron such as A. sertularice, assuming that the
proboscidiform organ with its terminal cirri is homologous with the erect stem
and tentacular sheaf of the first-named type. It is recorded by Mr. Levick that the
growing terminations of the branches of the adult colony-stocks of Dendrosoma
radians are not only soft and plastic, but highly polymorphic, the granular particles
of its component protoplasm flowing from one part to another and altering the
contour much after the manner of the body of an Amoeba. Such plasticity is, how-
ever, by no means characteristic of the fully matured parts, throughout which the
author has satisfied himself that a distinct cuticular membrane is developed, such,
indeed, showing under high magnifying power, as treated with osmic acid and
picrocarmine, a conspicuously marked double contour. In its first-formed condition
it is nevertheless soft and tenacious, permitting the adhesion of foreign bodies,
which are often present in such quantity as to entirely preclude distinct vision
of its true limits.

The author has very recently, March 1882, obtained fine examples of this
interesting type, through Mr. F. J. Fry, from a pond in the neighbourhood of Clifton,
Bristol, its tolerable abundance in the same neighbourhood having been further
certified to the author by Dr. C. T. Hudson. Among the nearly allied associates
of this type observed by the author in connection with the specimens remitted from
Birmingham may be more especially mentioned Adneta grandis, A. lemnarum,
and A. mystarina var. longipes. Professor Leidy* has reported the occurrence of
Dendrosoma radians in American waters.

Dendrosoma Astaci, Stein.

Under the above title, Stein t briefly refers to a species of Dendrosoma found
by him attached to the fresh-water crayfish, As focus fluviatilis. No characters,
however, have as yet been cited by which it may be distinguished from the preceding
type, and taking into consideration the usually fluviatile habitat of D. radians it
would seem highly probable that the two are identical.

* ' Proc. Acad. Nat. Hist. Philadelphia,' 1874.

t ' Der Organismus der Infusionsthiere,' Abth. i. p. 93, 1859.

846 ORDER TENTACULIFERA-ACTINARIA.

Order II. TENTACULIFERA-ACTINARIA, S. K.

None of the tentacles suctorial or capitate.

Fam. I. EPHELOTmZE, S. K.

Tentacles filiform or ray-like, prehensile, developed separately from the
body as in the ordinary Acinetidae.

GENUS I. EPHELOTA, Str. Wright.

Animalcules solitary, fixed, elevated on a rigid pedicle, having no
indurated lorica or investing membrane; tentacles flexible, more or less
retractile or invertile, not suctorial or capitate at their extremities.

The genus Ephelota, as instituted by Dr. Strethill Wright,* was formed for the
reception of certain infusorial types apparently closely allied to Podophrya, but
having pointed flexible tentacles in place of the suctorial ones that distinguish the
last-named genus. Of the two species described by this writer, there can be no
doubt that the first-named and typical species, Ephelota apiculosa, is identical with
the Podophrya Trold described a short time previously by Claparede and Lachmann,
and which is distinguished by these authorities from all other members of the genus
by the pointed and ray-like instead of suctorial character of the tentacles, and which
tentacles are further characterized by the abrupt thickening and comparative rigidity
of their basal portions. The much fuller details of the species given by Claparede
and Lachmann, and more especially those recorded by them in reference to the
manner in which food is ingested, unmistakably indicate that the form not only
requires a separate generic position, as recognized by Strethill Wright, but must
likewise be accepted as the type of a separate and highly important family group,
which it is here proposed to distinguish by the title of the Ephelotidae. Thus, while
Podophrya and other ordinary Acinetse merely absorb the semi-fluid contents of their
prey through their tubular suckers, Ephelota is found to seize the same with the
attenuate and apparently adhesive distal extremity of its tentacula, and by an
inverted action to drag its prey bodily through the more expanded basal portion of
these structures, and thence into the substance of its body. The author was at first
disposed to refer the Zooteira relegata of Strethill Wright to this, same family of the
Tentaculiferous Infusoria, but from a recent examination of that organism has
determined its close structural correspondence with the Radiolarian genus Actinqphrys,
of which it may be regarded as a stalked representative.

Ephelota coronata, Str. Wright. PL. XLVIIlA. FIGS. 1-3.

Body ovate, pyriform, or subquadrate ; tentacles numerous, slender,
and acuminate, flexible and almost completely retractile, radiating from all
points of the periphery, or forming a crown at the anterior border,
gradually tapering towards their apex, and not exhibiting an abrupt basal
dilatation, as in E. Trold ; pedicle diaphanous, usually longitudinally
striate, three or four times the length of the body, widest at its point of
junction with the same ; gradually narrowing as it approaches the attached
or proximal end. Length of body 1-400". HAB. — Salt water.

An animalcule corresponding essentially with the above diagnosis has been met
with by the author attached to zoophytes and Polyzoa on both the Guernsey and

* 'Edinburgh New Philosophical Journal,' 1858.

GENUS EP HELOT A. 847

Jersey coasts, and is evidently identical with that form upon which the above title was
first conferred by Strethill Wright. In describing the tentacles of this species more
minutely, that authority remarks that in some examples he found "a bundle or
framework of fine parallel rods imbedded in the soft contractile sarcode," while
other examples exhibited a " beaded " structure only. In all the specimens
personally examined, this last-mentioned beaded or coarsely granular structure was
apparent, but no trace could be detected of the rod-like bodies, which were therefore
possibly adventitious substances. As observed by Dr. Wright, the tentacles are
flexible, and capable of being curved inwards, but in a more active manner than he
has described ; one or more of these tentacles, in fact, as observed in association
with fully expanded examples, were constantly being bent down and inwards until
their points touched the margin of the periphery, and were then immediately raised
up and extended to their former erect position. The method by which food is
incepted in this form has up to the present time eluded all efforts to determine.
This may be accomplished by the withdrawal into the substance of the body of a
single tentacle carrying with it its captured prey, as in the species next described ;
or, possibly, the food, after capture by the extended tentacles, is deposited upon the
surface of the periphery simultaneously with the systematic inward flexure of the
same just noticed, and then incepted through the soft cuticular sarcode. Should
this last hypothesis, however, prove to be correct — and it is almost impossible
to get rid of the idea that some such function is associated with the persistent
deflection of the tentacles — this form cannot be retained among the Stomatode
Infusoria, but will find its true place, under a new generic title, among the Radiolaria
somewhere near Schulze's Actinolophus pedunculatus. That it is not identical with
this last-named type, the author is in a position to determine, through having
encountered that interesting type in the neighbourhood of Jersey, under very similar
conditions.

As intimated by Dr. Strethill Wright, the tentacles of Ephelota coronata cannot
be completely withdrawn. In the most contracted conditions personally observed, the
animalcules presented the aspect shown at PI. XLVIII. Fig. 3, in which the tentacula
form a small crown of short incurved digitiform prolongations around the apical
extremity. The form and position of the endoplast or nucleus in this species
remains as yet undetermined.

Ephelota Trold, C. & L. sp. PL. XLVIIlA. FIG. 5.

Body subspheroidal ; tentacles distributed singly and irregularly over the
entire surface of the periphery, each consisting of a short, thickened, slightly
elastic but not entirely retractile, tubular basal portion, and a slender,
elongate, completely retractile, ray-like distal part ; pedicle twice the length
of the body, sinuous, moderately thick and even throughout ; contractile
vesicle single. Diameter of body 1-350".

HAB. — Salt water, attached to seaweeds and Sertularia.

This species, as previously intimated, is identical with the Podophrya Trold of
Claparede and Lachmann and the Ephelota apiculosa of Dr. Strethill Wright, the
specific title of the latter authority having, however, in accordance with the laws of
priority, to give way to the earlier one bestowed upon it by the French savants,
who first discovered the type on the Norwegian coast in September of the year 1858.
As shown by these last-named investigators, the thickened basal portion of the ten-
tacles of this species, although not retractile, are highly dilatable, permitting
the passage of food-particles of considerable size. In illustration of this fact, it is
recorded by the Swiss observers that examples were seen to seize specimens of Tin-
tinnus denticulatus and to pass them whole through the tubular basal portion of their
tentacles, while in one instance a zooid was similarly observed to seize a Tintinnus
simultaneously by two of its tentacula, and, after tearing it in half by their united

ORDER TENTACULIFERA-ACTINARIA.

action, to engulph the divided fragments at separate regions of its body. The
extrusion from and withdrawal into the thicker basal portion of the ray-like distal
extremities of the tentacula of this species may be compared to the introversion
and extension of the fingers of a glove. The thickened and tubular basal parts,
with the fine, ray-like distal portions entirely retracted, are slightly dilated at their
free end and present, as shown at a a, in PI. XLVIIlA. Fig. 5, an aspect closely
resembling the shortened tubular suckers of the ordinary Acinetae. When, on the
other hand, the ray-like part is completely everted, the basal part exhibits, as shown
in the same figures, a more elongate, conical outline. Two embryos having the
surface of their bodies entirely ciliated were observed by Claparede and Lach-
mann to make their escape from one of the examples that formed the subject of their
investigations.

GENUS II. ACTINOCYATHUS, S. K.
(Greek, actin-, ray ; kuathos, a cup.)

Animalcules solitary, fixed, secreting an indurated pedicellated lorica ;
tentacles more or less retractile, not furnished with suctorial or capitate
extremities.

This genus is herewith instituted for the reception of those infusoria which,
while corresponding with Ephelota in individual form and structure, exhibit by their
secretion of a membranous sheath or lorica a relationship with that type parallel
to that which exists between the respectively loricate and illoricate genera, Arineta
and Podophrya. A single species only can at present be referred to this genus,
the same being an inhabitant of salt water.

Actinocyathus cidaris, S. K. PL. XLVIIlA. FIG. 6.

Body subspherical, slightly flattened, with numerous and, when partly
contracted, thickened muricate or echinulate tentacles, issuing chiefly from
the anterior extremity ; lorica cup-shaped or patellate, tapering posteriorly,
mounted on a slender, rectilinear pedicle of about three or four times the
length of the lorica ; contractile vesicle single or double. Diameter
of body 1-650". HAB. — Salt water.

Three or four examples of this animalcule were met with in February 1878,
attached to the external surface of the calcareous sponge Grantia compressa,
obtained at St. Heliers, Jersey. In none of these specimens, although watched for
a considerable interval, were the tentacles seen protruded to a greater extent than is
represented in the accompanying figure, though it may be anticipated that their
capacity of extension is much more considerable. The body of the zooid, whose
height and diameter closely correspond with those of the lorica, is never completely
enclosed within this structure, but merely rests upon it with all but the basal portion
exposed, in a manner almost identical with that previously described of Acineta
patula. Taken separately, indeed, the protective sheaths of these two species
present considerable resemblances, the chief point of distinction being the absence
in the type now under consideration of the narrow constriction of the pedicle at its
point of junction with the lorica that distinguishes the Acineta. This form does
not appear to be permanently connected with its lorica, an entirely naked, freely
detached zooid having been met with in close vicinity to the attached, loricate
examples. It is at the same time possible that this individual represented the newly
formed product by fission or gemmation of an ordinary loricated specimen. The
specific name proposed for this animalcule bears reference to the likeness to a
minute Cidaris presented by the subspherical body, taken in conjunction with the

GENUS OPHRYODENDRON. 849

radiating muricate or echinulate tentacles. These last-named organs, viewed
separately, might in a like manner be appropriately compared with certain
echinulate hairs of the larvae of Dermestes lardarius.

Fam. II. OPHRYODENDRID^E, S. K.

Tentacles apparently united so as to form one or more distinct
proboscidiform appendages, the distal terminations of which are naked or
cirrate.

GENUS I. OPHRYODENDRON, C. & L.

Animalcules mostly associated in colonies, but not organically connected,
attached in a sessile manner, or through the medium of a pedicle, usually
dimorphic, or including two distinct structural types ; zooids of the first order
ovate or pyriform, with a long, extensile and retractile, anterior, proboscidiform
organ bearing numerous flexible cirrose appendages at its distal extremity ;
zooids of the second order vermiform or flask-shaped, developed anteriorly
into a slender and apparently tubular neck having a small terminal orifice ;
contractile vesicle single or multiple; endoplast nodular or ramifying,
rendered visible only by the action of reagents. Increasing by gemmation
and by the production of ciliated embryos. Inhabiting salt water.

Attention was first directed to the singular organisms referred to this genus by
Claparede and Lachmann, who discovered the type-form O. abietinum on the coast of
Norway in the autumn of the year 1855, and included a description of it in their
Memoire on the Infusoria communicated to the Paris Academy of Sciences that
same year. Dr. Strethill Wright subsequently described a closely allied type under
the title of Corethria sertularia in the ' Edinburgh Philosophical Journal ' for July
1859 (description and figures reproduced in Pritchard's 'Infusoria,' ed. iv. 1861);
and the Rev. Th. Hincks has since given a more exhaustive account of O . abietinum,
supplemented with the description of a third species, 0. pedicellatum, in the ' Quar-
terly Journal of Microscopical Science ' for January 1873. Several species have been
yet more recently discovered, but notwithstanding the attention bestowed upon them
by these various independent investigators, it cannot be said that the true nature and
affinities of the genus have as yet been accurately determined, and neither, on the
other hand, has a sufficiently satisfactory explanation so far been accorded concern-
ing the apparently anomalous phenomenon of dimorphism associated with the several
representatives of the genus. By Claparede and Lachmann, the vermiform or non-
proboscidiform zooids of O. abietinum, though figured, are passed over as merely
normal proboscidiform animalcules or varieties of the same with their probosces
retracted. Mr. Hincks, on the contrary, favours the opinion that the two represent
adult and dimorphic conditions of the same form. The author's opinion concerning
this anomalous generic group, gained from a personal acquaintance with a variety
of species, combined with a study of the evidence adduced by the several
authorities already quoted, is that the non-proboscidiform or vermiform zooids must
be regarded as the larval or transitional condition of the fully developed zooids
provided with their characteristic probosces. It is clear from the testimony con-
tributed in all these instances, that the simpler vermiform zooids are produced by
gemmation from the proboscidiform ones, but never these latter from the former,
while the true internal embryos, corresponding with those of other typical Acineta,
are also forthcoming in a similar manner from the proboscis-bearing animalcules only.
Again, while frequently encountering these latter alone, or in isolated groups,
the vermiform zooids appear almost invariably to occur only in companionship
with the proboscidiform ones, or as derivatives by gemmation from them.

VOL. II. 2 C

850 ORDER TENTACULIFERA-ACTINARIA,

Although the further development of the vermiform into the proboscidiform zooids has
not so far been determined, it is clear that little beyond the everting of the neck-like
anterior region of the former is requisite to bring about such a result. The view
here expressed is substantially supported by the evidence given by Fraipont in
connection with his very recent description of Ophryodendron Helgicum, in which
type, indeed, he records the occurrence of and figures intermediate phases.

The affinity of the members of the genus Ophryodendron with the normal
Acinettz is predicated through the assumed correspondence of the proboscis-like
prolongation and terminal cirri of the typical zooids with the suctorial tentacles
of the latter. No evidence has, however, yet been adduced showing that these
filaments or the extensile proboscis itself possess a similar suctorial capacity,
nor, indeed, is it yet known in what manner the organism grasps or incepts its food.
Pending the satisfactory elucidation of this most important point, it seems most
reasonable to premise that food-substances are seized by the brush-like filamentous
tuft or distal end of the proboscis itself, and then withdrawn with it into the
parenchyma of the body. Should this view prove correct, the retractile proboscis
will be shown to be homologous with the non-suctorial but adhesive tentacles of the
genus Ephelota, concentrated, however, into the form of a single and proportionately
larger terminal tentaculum. In this connection it may be further submitted that
the transverse subspirally disposed rugas that form so conspicuous a feature of the
proboscis of Ophryodendron when examined under high magnification, are both
functionally and morphologically identical with the delicate granular fibrillas which in
a similar manner encircle the individual tentacles, whether suctorial or simply
adhesive, of various ordinary Acinetidae, such as Podophrya elongata and Hemiophrya
gemmipara.

Ophryodendron abietinum, C. & L. PL. XLVIIlA. FIGS. 13-15 AND 32.

Primary or proboscidiform zooids cup-shaped or pyriformj with a cleft
on one side of the anterior margin, tapering posteriorly, and adherent by
an annular disk-like expansion ; proboscis long, slender, cylindrical, highly
extensile, pointed at its apex, and bearing a brush-like tuft of twenty or
thirty tentacular filaments ; secondary or vermiform zooids (larvae ?) ovate
or vermiform, rounded or slightly pointed posteriorly, produced at the
opposite extremity into a long, slender, tubular neck, and usually mounted
on a straight setose pedicle ; parenchyma of the body generally enclosing
innumerable minute refringent navicula-shaped corpuscles. Length of body
of primary or proboscidiform zooids, without the proboscis, 1-175" to 1-30" ;
of the vermiform zooids 1-150" to 1-30".

HAB. — Salt water, attached to the polyparies of Sertularia, Plumularia,
and other Hydrozoa.

Oval ciliated embryos were liberated artificially by pressure from the paren-
chyma of examples of this species examined by Claparede and Lachmann. This
ciliation is limited to one surface only of the embryo, as occurs in Podophrya
cothurnata, Hemiophrya gemmipara •a&.di-Dendrocometesparadoxus, and may be thus said
to follow a hypotrichous plan. The further development of these embryos remains
to be traced, and is likely to be of much interest. In addition to the ordinary pro-
duction by gemmation of the vermiform zooids, Claparede and Lachmann figure an
example in which a proboscidiform zooid is in course of production in a somewhat
similar manner from another of the same form. On reference to the figure cited,
however, one is inclined to interpret this example as illustrating the phenomenon
of longitudinal fission rather than that of peripheral gemmation. The specific name
of abietinum has been conferred upon this species by its discoverers, with reference

GENUS OPHRYODENDRON. 851

to the fanciful resemblance of the extended proboscis with its terminal tuft of cirri
to a miniature fir or larch. These cirri, in the form now under consideration, are
longest at the basal part, becoming gradually shorter as the apex is approached, and
in the living state are in a condition of constant agitation, as though seeking for
appropriate food. The proboscis becomes transversely annulate in its semi- or com-
pletely retracted state, and is extended or withdrawn with remarkable rapidity.

The navicula-shaped bodies observed by Claparede and Lachmann in examples
of this species, and regarded by them as " trichocysts," are apparently of an adventi-
tious nature, not being equally constant in individuals derived from the same locality,
and are altogether absent in the specimens from the Welsh coast examined by
Mr. Hincks. In consequence of the dark granular nature of the parenchyma, these
same authorities, while suspecting the existence of an endoplast and contractile vesicle,
were not able absolutely to determine its presence.

Prof. C. Robin, in a recent reference to Ophryodendron abietinum* expresses the
opinion that the vermiform zooid is a parasitically attached worm-larva, and describes
it as being affixed to its host through the medium of a slender chitinous rod, one end
of which is imbedded in its own body-substance, while the other penetrates the cuticle
of its host, and is armed, see PL XL VI 1 1 A. Fig. 32, with four or five booklets which
serve to anchor it in its attached position. The intermediate phases which have
been observed by Fraipont, Claparede and Lachmann, and other authorities do not
appear to have fallen within the notice of this investigator.

Ophryodendron sertulariae, Str. Wright sp. PL. XLVIII. FIGS. 38-40.

Body of primary or proboscidiform zooids subcircular or elliptical,
sessilely attached, very much depressed or flattened ; the proboscis
flattened, transversely rugose, developed eccentrically in close proximity to
the lateral periphery ; terminal cirri of the proboscis varying from about
twenty to forty or fifty in number; vermiform zooids elongate, attached
without the medium of a distinct pedicle to the body of the primary zooids,
or to some foreign object; a branching endoplast and one or more
contractile vesicles discernible in the more transparent proboscidiform
zooids. Diameter of bodies of primary zooids 1-300"; length of vermiform
animalcules 1-200". HAB. — Salt water, on Sertularia pumila.

This species, which is synonymous with the Corethra sertularia of Dr. Strethill
Wright, has been regarded by many authorities as identical with the Ophryodmdron
abietinum of Claparede and Lachmann. That the two are distinct from each other has,
however, been anticipated by Koch and Fraipont, and that such opinion is correct, the
author, through a personal acquaintance with Strethill Wright's type, is in a position
to substantiate. So recently as August and September 1881, this form has been
obtained by him in great numbers, attached to the polyparies of the zoophyte on
which it was originally discovered, growing on Fuci collected in the Menai Straits,
North Wales, Acineta tuberosa and A. livadiana being abundantly represented in its
vicinity. The most conspicuous features, by which it may be readily distinguished
from the forms which it most nearly resembles, viz. O. abietinum and O. porcellanum,
. consist of the remarkably depressed contour of the body of the primary zooids and
the essentially eccentric or peripheral development of the proboscis. This last-named
feature, though indicated in Strethill Wright's original drawings, has not so far been
specially mentioned by any writer. In some of the more transparent specimens
preserved with osmic acid, a band-like, variously branching endoplast or nucleus,
and one or more contractile vacuoles were distinctly visible. The proboscis, under

* 'Journal of Anatomy and Physiology,' 1879; also 'Journal of the Royal Microscopica
Society,' October 1880.

2 C 2

852 ORDER TENTACULIFERA-ACTINARIA.

high magnification, corresponds in contour, structure, and comportment with that
of Ophryodendron porcellanum, next described, but the terminal cirri are much less
numerous. These cirri, under the same conditions, were observed to be very dis-
tinctly granular and adhesive. Attempts to make the animalcules incept carmine
particles, or to ingest any other food, were not rewarded with success. The indepen-
dent vermiform zooids in the process of mounting became readily detached from their
fulcra of support, their surface of adhesion being demonstrated in this connection
to be simply acetabulate.

Ophryodendron porcellanum, S. K. PL. XLVIIlA. FIGS. 20-25.

Body of primary zooids sessile, subspherical, or cushion-shaped ; the
proboscis highly extensile, developed subcentrally, flattened and trans-
versely rugose ; its apex bearing a brush-like tuft of innumerable cirrate
processes ; secondary zooids sessile, attenuate vermiform, independent or
associated with a basal cushion-like body similar to that of the primary
animalcules. Length 1-400".

HAB. — Salt water : Jersey (S.K.), on the limbs of the flat-crab, For-
cellana platycheles.

When first discovered by the author at St. Heliers, Jersey, in March 1878, this
species was supposed to be identical with either the Ophryodendron sertularice. of
Strethill Wright or the Ophryodendron abietinum of Claparede and Lachmann. While
a subsequent acquaintance with the first-named type enables the author to dis-
tinguish it from the first-named form, in connection more especially with its less
depressed body and redundant development of cirri at the extremity of the pro-
boscis, the following points may be cited, in addition to its habitat, as separating it
distinctly from O. abietinum. In the first place, the body of the proboscidiform
zooids is never elongate cup-shaped or pyriform, as in O. abietinum, but always
presents a subspherical or slightly flattened contour. The zooids of the second order
are, again, when isolated, much more elongate or vermiform. More often, however,
as personally examined, these vermiform individuals have been associated with a
subspherical body similar to that of the primary zooids (PI. XLVIIlA. Fig. 23), and
from which, indeed, they are indistinguishable but for the exception that the
characteristic proboscis is here replaced by a long spout-like tube. This tube, it
may be reasonably anticipated, is homologous with the proboscis of the primary
forms, and develops later on into the same In other minor details, such as the
flattened form of the proboscis, as also in the greater number of the cirrose filaments,
this species is readily distinguished from either of the preceding types. On no
occasion could less than fifty or sixty of these cirrose filaments be counted, while in
many instances they were found to exceed one hundred. These terminal cirri, when
examined with the aid of a magnifying power of from 800 to 1000 diameters,
were found to be eminently tenacious, adhering readily to the surface of the glass
object-carrier, and at times, during the act of extension of the proboscis, progressing
over its plane surface by an apparently independent creeping action.

Ophryodendron pedicellatum, Hincks. PL. XLVIIlA. FIG. 16-19.

Zooids of both classes furnished with slender curved pedicles : body of
primary or proboscidiform zooids symmetrically cup-shaped, with an
even, sharply defined anterior border; proboscis cylindrical, attenuate,
highly extensile, bearing at its extremity eight or ten subequal tentacular
processes ; secondary zooids flask-shaped, attenuate anteriorly. Dimensions
unrecorded.

HAB. — Salt water, on Plumularia pinnata ; Ilfracombe, Devonshire.

GENUS OPHRYODENDRON. 853

A full account of this interesting and very distinct species was communicated by
Mr. Th. Hincks to the ' Quarterly Journal of Microscopical Science ' for January
1873. The regular cup-shaped body seated on its slender curved pedicle at once
distinguishes the primary zooids of this form from those of the preceding one, while
in addition, the group of tentacular processes, depressed during extension in a radiate
rather than in a brush-like manner, at the distal extremity of the proboscis, are
much fewer in number and apparently of equal size, instead of being longest at
the base and gradually diminishing as the apex is approached. The secondary or
vermiform zooids closely correspond with those of O. abietinum, and are only
distinguishable from them by their curved instead of rectilinear pedicle. In one
instance two zooids of this denomination were observed with their pedicles united
for a portion of their length, and in all probability represented an instance of
longitudinal fission. These secondary vermiform zooids, of both this and the
preceding species, are described by Mr. Hincks as being particularly active in their
movements, constantly swaying themselves gracefully to and fro in all possible
directions, now sweeping the surrounding water, now passing the oral extremity of
the neck over the surface of the polypary on which the colony is planted, and now
reaching over towards the proboscidian zooids, and bringing themselves into frequent
contact with the trunks and probosces of this series. The primary or proboscidian
zooids are, on the other hand, comparatively quiescent, restricting their motions
chiefly to the extension and retraction of their trunk-like proboscis, but which may
be thus extended or withdrawn with amazing swiftness.

The species of Ophryodendron described by Koch* under the title of O. peduncu-
latum, and obtained by him at Messina, is, as recognized by Fraipont, apparently
identical with Mr. Hincks's type.

Ophryodendron Belgicum, Fraipont. PL. XLVIII. FIGS. 36 AND 37.

Proboscidiform zooids elongate-pyriform or clavate, often furrowed
anteriorly, attached by a sucker-like expansion of the more attenuate
posterior extremity ; proboscis evertile to about one-half of the length of
the extended body, its distal end bearing from five or six to not more than
eight tentaculoid cirri ; parenchyma opaque, frequently inclosing numerous
refringent navicular corpuscles ; endoplast, rendered visible only by the
action of reagents, in adult examples more or less irregularly branched ; a
vacuolar space, apparently representing the contractile vacuole, usually
developed towards the anterior region of the body, and occasionally a
second one near the posterior extremity. Vermiform zooids subcylindrical
or clavate, seven or eight times as long as broad, affixed posteriorly by a
slender rigid pedicle when young, but subsequently attached in a sessile
manner ; parenchyma resembling that of the proboscidiform zooids, and in a
similar manner frequently inclosing refringent corpuscles ; endoplast and
vacuolar spaces as in the proboscidiform examples, but the first-named
structure less complex. Length of proboscidiform zooids 1-400" ; of
vermiform zooids 1-400".

HAB.— Salt water : Ostend, on the hydrothecae of Clitia volubilis.

Apart from its size and habitat, the chief distinction between this type and
Ophryodendron abietinum would seem to subsist in the less luxuriant development
of the tentacular appendages of the proboscis. Notwithstanding, however, such

* " Zwci Acincten auf Plumularia setacea." Jcua, 1876.

854 ORDER TENTACULIFERA-ACTINARIA.

similarity as exists, M. Fraipont* has succeeded in eliciting, through a careful study
of its structural and developmental history, many points of high interest not hitherto
recorded in connection with this very remarkable generic group. Among the most
important data thus determined must be mentioned his demonstration that this
form, in common with the more normal Acinetidse, possesses a well-developed
nucleus or endoplast. Such a structure, while not visible during life, and not hitherto
observed in any other species of Op/iryodendron, was rendered distinctly visible in
examples first treated with absolute alcohol, and afterwards immersed in picrocarmine.
Although not observed to contract, M. Fraipont has no hesitation in identifying the
vacuolar space, in most cases conspicuous towards the anterior extremity of the
body, as identical with the pulsatory contractile vesicle of the ordinary Acinetidae and
other Infusoria. In Podophrya gcmmipara, as attested to by Hertwig, an interval of
several hours may elapse between the systolic contractions of this vesicular structure,
and may consequently in the present instance recur at even longer intervals. With
reference to the vermiform zooids, M. Fraipont adheres to Claparede and Lach-
mann's original interpretation that they represent an immature condition only of the
proboscidiform individuals, and supports his decision with figures and descriptions
of transitional phases between the two. These vermiform zooids, as in O. abietinum,
are derived as gemmules from the proboscidiform units, into which a portion of
the parent endoplast is extended ; in this species, however, the gemmules either take
a vermiform contour or pass directly to the proboscidiform condition. The navi-
cular refringent corpuscles enclosed within the parenchyma of this species in
common with O. abietinum, M. Fraipont is inclined to identify with the trichocysts
of the Infusoria Ciliata.

Ophryodendron multicapitatum, S. K. PL. XLVIIlA. FIGS. 26-31.

Bodies of primary proboscidiferous zooids variable in shape, ovate, sub-
spherical, or pyriform, distinctly pedicellate when young or half-grown,
sessile in their adult state ; the adult zooids usually supporting as many
as four subterminally developed proboscidiform organs, whose distal
extremities bear from thirty to forty cirrose appendages ; the secondary
or vermiform zooids elongate, developed in company with a variable number
of ovate or subspheroidal gemmules around the bases of the proboscidi-
form organs ; endoplast or contractile vesicle not observed. Height of
adult proboscidiferous zooids 1-300".

HAB. — Salt water, attached to the limbs of an Isopodous crustacean.

This very rematkable form was obtained by the author in March 1879, during a
few days spent in the collection of marine specimens among the group of rocks lying
midway between France and the island of Jersey, known to fishermen as the " Min-
quieres." Some dozen specimens in various stages of development were thus obtained,
attached chiefly to the antennae and ambulatory appendages of a small Isopod
apparently most nearly allied to the fresh-water genus Asellus. The most remarkable
feature concerning this species, which will be immediately recognized, consists of the
abnormal number of proboscidiform organs, these in the adult examples numbering no
less than four, and two or three being commonly present in those less developed.
In a like manner, the number of germs developed simultaneously upon the anterior
border of the body usually coincide more or less nearly with that of the probosces,
and in both instances exceed what obtains in any species hitherto described. The
metamorphoses undergone by the anteriorly developed germs after detachment from
the parent zooid, and prior to their arrival at the adult state, are of considerable
interest. In the first place, as shown at PI. XLVIII. Fig. 29, the body, as in the

" Acinetiens dc la Cote d'Oslencle," 'Bull. Acad. Eruxelles,' 1879.

GENUS A CINE TO PS IS. 855

adult form, is simply spheroidal, but attached to its fulcrum of support by a
distinct rigid pedicle. A little later the zooid assumes a pyriform contour, a single
terminal proboscis is developed, and the animalcule, as delineated at Fig. 30, most
nearly resembles the typical form of O. pedicellatum, represented by Figs. 16 and 17
of the same plate. This pedicle may be retained even after the zooid has attained
to a considerable size, developed a plurality of proboscidiform organs, and com-
menced to propagate by gemmation, as shown at Fig. 28 ; by the time, however,
that the full size and complete number of probosces are developed, the pedicle has
invariably disappeared, having become either completely surrounded and enclosed
within the distended body-mass, or possibly reabsorbed into its substance. The
densely granular and opaque character of the parenchyma in this type prevented
the clearing up of this point, and neither, owing to the same conditions, was it found
possible to detect the presence of either contractile vesicle or endoplast. The
vermiform larvae were but sparingly observed in the examples examined ; they
corresponded essentially in form and structure with those of Ophryodendron sertularice,
previously described.

It will probably be found convenient hereafter to introduce a new generic title
for this and any allied species that may be discovered possessing a plurality of
proboscidiform appendages. In connection with this distinctive feature, it might,
perhaps, be maintained that Ophryodendron multicapitatum potentially represents a
polyzoidal colony-stock after the manner of Dendrosoma; on the other hand, a
near comparison with reference to these appendages might be instituted with
Dendrocometes paradoxus, illustrated immediately above it in PI. XLVIIlA., assuming
necessarily in this case that each proboscis of the Ophryodendron is, as in the branch-
like extensions of Dendrocometes, the homologue of the number of tehtaculate organs
normally developed by the simpler Acinetidae.

GENUS II. ACINETOPSIS, Robin.

Animalcules ovate, excreting and inhabiting a stalked, membranous,
transparent lorica, bearing a single, anteriorly developed, contractile,
proboscidiform tentacular appendage, the distal extremity of which is not,
as in Ophryodendron, beset with supplementary cirri. Inhabiting salt
water.

Acinetopsis rara, Robin. PL. XLVIII. FIGS. 43-45.

Lorica wineglass-shaped, transparent, about one and a half times as
long as broad, mounted on a very slender, straight or flexuose pedicle that
equals or slightly exceeds the lorica in length ; body almost completely
filling the cavity of the lorica, its substance uniformly granular ; probosci-
diform tentacle very attenuate or filiform when extended, its length then
equalling five or six times that of the body, exhibiting throughout
when contracted an exteriorly developed, very delicate, plicate, spiral
fibrilla ; contractile vesicle single, subspherical ; endoplast unobserved.
Length of lorica 1-300".

HAB. — Salt water, on various Sertularian zoophytes : Concarneau
(Ch. Robin).

This very remarkable form is figured and described by Prof. Ch. Robin in the
' Journal de 1'Anatomie et de la Physiologic,' torn. xv. 1879,* and is of more than

* Sec also translation in 'Journal of the Royal Microscopical Society,' Oct. 1880.

856

APPENDIX.

ordinary interest since it serves to unite the anomalous genus Ophryodendron with
the more typical Acinetidae. This is more especially manifested in connection with
its possession of a membranous lorica, and in the non-development of motile cirri
at the extremity of the single proboscidiform tentacle. This tentacle, moreover,
in addition to its simple structure, coincides in the circumstance of its delicate
externally developed spiral fibrilla with the slender prehensile tentacle vl Hemiophrya
gemmipara. Taken*as a whole, the general structure of Acinetopsis would appear
to be not so very remote from that of Urnula ; it is an open question, indeed,
whether the two extremities of the Tentaculiferous series might not be consistently
united at this point. The act of food-ingestion, as in the case of Ophryodendron,
has not as yet been witnessed, but it was observed that the extended tentacle was
capable of motion in every direction. The resemblance subsisting between a
zooid of this species and the peculiar thecated sarcodic appendages, the so-called
" nematophores " of certain Hydroid zoophytes, has been referred to at page 805.

APPENDIX TO VOL. II.

NOTICE OF SUPPLEMENTARY SPECIES AND MORE IMPORTANT DISCOVERIES CON-
CERNING THE INFUSORIA RECORDED DURING THE PUBLICATION OF THIS
WORK, OR ACCIDENTALLY OMITTED FROM INSERTION UNDER THEIR RESPEC-
TIVE HEADINGS.

CLASS I. Flagellata.

GENUS Dimorpha, Gruber. — Animalcules free-swimming, dimorphic, reverting
at will from a Heliozoidal or Actinophrys-like phase to a simple monadiform condi-
tion, or vice vers&; in either state bearing two long, closely approximated vibratile
flagella.

Dimorpha nmtans, Gruber. — Zooid in its monadiform condition symmetri-
cally ovate, wider and somewhat truncate at the anterior border, tapering gradually
towards the posterior extremity ; flagella subequal, about twice the length of the
body, inserted close to each other near the centre of the anterior border; paren-
chyma transparent near the front margin, granular throughout the remaining area,
usually enclosing digested food-substances in the posterior region of the body;
contractile vesicle single, subcentral ; endoplast imperfectly observed. In its
Actinophrys phase, the body spheroidal or slightly elongated, bearing in addition to
the two vibratile flagella numerous slender, finely granular, ray-like pseudopodia,
having a fully extended length of two or three times the diameter of the body, and
which decussate from the periphery in every direction. Diameter of body of
Actinophrys-like phase 1-1600". HAB. — Fresh water.

This highly interesting species, recently figured and described by Dr. August
Gruber,* was obtained by him in some abundance from a slowly flowing canal in the
neighbourhood of Lindau. As rightly inferred by its discoverer, it constitutes an
intermediate or annectant type between the respective groups of the Flagellata and
the Heliozoarian section of the Radiolaria. It is indeed very closely allied to the two
marine forms, apparently unknown to Dr. Gruber, figured and described by the

* " Dimorpha mutatis, eine Mischform von Flagellaten und Heliozoen," ' Zeitschrift fur Wissen-
schaftliche Zoologie,' Band xxxvi. Heft 3, December 1881.

APPENDIX. 857

author in Vol. I. p. 227 of this treatise under the title of Actinomonas mirabilis and
A. pusilla* and is in like manner referable to the there newly established order of the
Radio-Flagellata.

The essential distinctions between these two forms subsist chiefly in the facts
that Dlmorpha leads an entirely free-swimming condition, never developing a pedicle
as in the case of Actinomonas, and possesses two in place of a single flagellate
appendage, as obtains in the last-named type. The highest interest attached to this
form is connected with the facility with which the metamorphoses from the simply
flagellate to the more complex Heliozoidal condition, or the converse, are brought
about, such changes, as observed by Dr. Gruber, being effected many times by the same
zooid within a single hour. In its simpler biflagellate condition Dimorpha is
scarcely to be distinguished from an ordinary member of the genus Heteromifa,
progression being effected in a similar manner with one flagellum vibrating in
advance and the other trailing in the rear. Food-ingestion, as observed of the
Heliozoidal condition only, is accomplished at all parts of the periphery. A somewhat
doubtful instance of transverse fission was witnessed in which one of the segmented
moieties retaining the two flagella swam off as a monadiform zooid, while the other,
throwing out pseudopodia, assumed an Actinophrys-like aspect.

Urceolus (Phialonema) Alenizini, Meresch. — Surface of the body smooth,
without striae : neck cylindrical, with the margins abruptly truncated and not turned
out. Dimensions unrecorded. HAS. — White Sea.

This species, though previously figured and described by Mereschkowsky in his
' Studien iiber Protozoen des Nordlichen Russland,' published in the ' Archiv fur
Mikroskopische Anatomic,' Bd. xvi , December 1878, was inadvertently passed over
by the author when chronicling the associated forms. In his more recent notice of
this species ('Annals,' March 1881), Mereschkowsky declares its generic identity
with the animalcule upon which Stein t has conferred the title of Phialone ma cyclostoma
(see Vol. I. p. 373), but from which form it is readily distinguished by the non-
striation of the cuticular surface and the evenly truncate contour of the frontal
border. Mereschkowsky further maintains that his name of Urceolus having been
bestowed upon the species he discovered, in a yet earlier Russian memoir which
appeared in 1877,} it will have to take the place of Stein's Phialonema in both
instances. It is at the same time worthy of remark that in Mereschkowsky's figures
and description no indication whatever is given of the existence of the prolonged,
posteriorly dilated pharyngeal passage that eminently distinguishes Stein's type, and
which is here accepted as affording a diagnostic generic character.

Anisonema quadricostatum, Meresch. — Body oval, strongly depressed,
ornamented on the dorsal surface with four longitudinally disposed ribs or costse.
Dimensions unrecorded. HAB. — Salt water : Bay of Naples, Sorrento.

" The oval body is characterized by its strong depression ; the cuticle, which
covers the whole body, is very firm and on the dorsal part it forms at the surface four
longitudinal elevations, four ribs, slightly spirally curved. The mouth, which is
widely open in the form of a vertical fissure, is very visible on the ventral surface,
from which originate two flagella, one of which trained along behind, attains two and
a half times the length of the body." §

Kiinckelia gyrans, Kunstler. — This species is briefly described by J.
Kunstler|| as a fresh-water Noctiluca. The body is capable of elongation, and
so enabled to creep about. There is an enormous tentacle which exhibits very
active movement when the animal is swimming. Under its cuticle there are two

* In Vol. I. pp. 226 and 227, and PI. I. Figs. 7, 8, and 10, published in Parts I. and II., October
and November 1880.

t ' Infusionsthiere,' Abth. iii. Heft i, 1878.

j 'Travaux de la Soc. des Naturalistes de St. Petersbourg,' vol. viii., 1877.

§ "C. Mereschkowsky on some new or little-known Infusoria," 'Annals and Magazine of
Natural History,' March 1881.

II 'Comptes Rendus,' xciii., 1881.

858 APPENDIX.

muscular layers which are continued into the tentacle. The mouth appears to lead
into a very large cavity. No phosphoric properties have been as yet observed.

A new species of Astasia receives from Kiinstler the name of Astasia costata ; it
is distinguished by its ribbed aspect, which is due to the presence in the integument
of regular rows of starch-grains ; the digestive apparatus consists of a narrow
oesophagus, a large gastric pouch, and an intestine leading to an anal aperture.

GENUS Proterospongia, S. K. Gr. proteros, earlier; spoggos, sponge. — This
generic title is herewith substituted for that of Protospongia, employed by the author
at Vol. I. p. 363, and which, though not included in either Agassiz' or MarschalPs
'Nomenclator Zoologicus,' has, he finds, been preoccupied by Zittel for the
distinction of a genus of fossil sponges.

ORDER Cilio-Flagellata.

An extensive and highly important memoir relating to that larger section of the
Cilio-Flagellata included in this treatise in the family group of the Peridiniidae, has
been recently published by R. S. Bergh, of Copenhagen.* In addition to supplying
elaborate details concerning the more minute histology and tendency to variation
of the many forms already known to science, some half a dozen species are here
figured and described for the first time ; no less than three of these being recognized
as types of new generic groups. Phylogenetically. Bergh is inclined to accept the
genus Prorocentrum rather than Gymnodinium as the stock-form or architype of the
Peridiniidae, and further predicates the evolution of the Peritrichous Ciliata through
Mesodinium from out of the Cilio-Flagellate order. Evidence that somewhat
favours this last-named speculation, but which does not appear to have attracted
Bergh's attention, might perhaps be adduced on the grounds that the characteristic
oral flagellum of the Peridiniidae finds its homologue in the abnormally prolonged
cilium or so-called " soie de Lachmann," developed from the same region in many
of the Vorticellidae.

One important change in the position that has been hitherto allotted to it has, as
a result of M. Bergh's recent investigations, to be made in connection with Btitschli's
somewhat problematical form Polykrikos Schwartzii, referred provisionally by the
author at page 509 to the Holotrichous family Colepidae. As demonstrated by the
Copenhagen authority in connection with a closely allied species, Polykrikos
auricularis, the generic group must be accepted as a somewhat abnormal Cilio-
Flagellate type, differing from the ordinary Peridiniidag in the more abundant
development of its ciliary girdles, the oral opening being at the same time sub-
terminal. The so-called oral seta, apparently produced in duplicate in the
example figured by Biitschli, is clearly shown by Bergh, in connection with P.
auricularis, to differ in no way from an ordinary attenuate vibratile flagellum.

The several new genera and species established by R. S. Bergh are as follows : —

Gymnodinium gracile, Bergh. — Body elongate-conical, from two and a half
to three and a half times as long as broad, subdivided by the transverse ciliary
furrow into a shorter acuminately pointed anterior and a longer obtusely rounded
posterior segment ; the longitudinal furrow very wide posteriorly j the external or
ectoplasmic layer folded and wrinkled ; no myophan layer ; colour pale pink.
Length 1-250". HAB. — Salt water: Baltic Sea.

Gymnodinium spirale, Bergh. — Body subfusiform, about three and a half
times as long as broad, the anterior abruptly narrowed and curved towards the
right, the posterior end forming terminally a short conical sword-like point ; the
transverse ciliary furrow taking a very oblique spiral course ; the ectoplasmic surface
smooth, inclosing a longitudinally striate myophan layer ; colour grey. Length of
body 1-400" to 1-250". HAB. — Salt water: Baltic Sea.

* " Der Organismus der Cilio-flagellaten, eine phylogenetische Studien,'' ' Morphologisches
Jahrbuch,' Band vii. Heft. 2, 1881, Ss. 177-288 und Taf. xii.-xvi.

APPENDIX. 859

Glenodinium Warmingii, Bergh. — Body suborbicular, compressed, about
twice as broad as long, subreniform as seen in horizontal section, divided by the
equatorial furrow into two distinct segments, the anterior one being much the smaller ;
cuirass membraneous, entirely smooth and homogeneous ; endoplasm orange-
coloured, inclosing chlorophyll, diatomin, and starch. Diameter of body 1-700" to
1-550". HAB. — Salt water : Baltic Sea.

GENUS Diplopsalis, Bergh. — Animalcules resembling those of Glenodinium^
the cuirass divided by a subcentral equatorial furrow into two subequal segments,
but neither reticulate nor separated into secondary plates or facets ; two delicate
membraneous crests, as in Dinophysis, developed from the sides of the longitudinal
furrow.

Diplopsalis lenticula, Bergh. — Body depressed lenticular, subcircular in
horizontal optic section, the membraneous crests of the longitudinal furrow not
strengthened by decurrent linear thickenings ; endoplasm inclosing chlorophyll and
diatomin, also a large transparent vacuole, representing probably the contractile
vesicle. Diameter of equatorial region of the body 1-125".

HAB. — Salt water : Baltic Sea.

GENUS Protoperidinium, Bergh. — Animalcules resembling short-horned or
cuspidate examples of the genus Ceratium, such as C. divergens, but their horn-like
processes, which consist of excurrent developments of the edges of the longitudinal
groove, united by membraneous crests to the general surface of the cuirass.

The membraneous crests developed as cuspidate processes of the carapace are
regarded by Bergh as modified homologues of the membraneous ventral plates of
Dinophysis, this last-named genus, in accordance with such interpretation, being thus
united to the typical genus Peridinium.

In addition to the following newly discovered type he proposes to include in the
same genus the Peridinium (Ceratium) Michaelis of Ehrenberg.

Protoperidinium pellucidum, Bergh. — Body subspheroidal, divided into two
even areas by the subcentral horizontal furrow, with two anterior membraneous
cusps, the posterior extremity developed into an attenuate, terminally toothed,
acuminate extension ; cuirass composed of numerous finely reticulate facets. Length
of body 1-450". HAB. — Salt water : Baltic Sea.

GENUS Protoceratium, Bergh. — Animalcules resembling those of Peridinium,
the cuirass divided by the equatorial furrow into two distinct segments, but these
segments simply reticulated and not separated into distinct secondary plates or
facets ; the longitudinal furrow, with the exception of the oral fissure and appended
flagellum, enclosed by the cuirass.

Protoceratium aceros, Bergh. — Contour of body ovate or subspheroidal,
closely resembling that of Peridinium tabulatum, but the ventral aspect not so dis-
tinctly flattened or concave ; the entire surface of the cuirass finely reticulate but not
subdivided into distinct parts ; endoplasm inclosing chlorophyll, diatomin, and
apparently starch-like corpuscles ; often with an eye-like pigment-spot. Length of
body 1-700". HAB.— Salt water : Baltic Sea.

Ceratium hirundinella, Mull. sp. — This species has been described in
Vol. I. p. 457, in connection with the title of Ceratium longicorne conferred upon it
by Perty. Bergh, however, would appear to be justified in identifying it with the
Bursaria hirundinella of O. F. Miiller, originally passed over by the author as pro-
bably representing the larva of some Turbellarian such as Monostomum, and this
specific name must consequently take the precedence. The so-called Ceratium
hirundinella of Dujardin is, as already shown at p. 462, identical with the Peridinium
(Dimastigoaulax) cornutum of Ehrenberg.

Polykrikos auricularia, Bergh. — Body subcylindrical or barrel-shaped, with a
scalloped or crenated lateral outline, obtusely rounded at the two extremities, about
two and a half times as long as broad, indented along the centre of the ventral

86O APPENDIX.

surface by the ventral groove in such a manner that the body as seen in optic
transverse section presents a kidney-shaped aspect : ciliary girdles eight in number,
disposed somewhat obliquely ; flagellum as long or longer than the body, issuing
from the ventral region of the apical ciliary girdle, distinctly thickened at its
proximal extremity ; endoplasts four in number, distributed in rectilinear order
through the central region of the body ; endoplasm coloured pink, enclosing scat-
tered apparent trichocysts, identical in structure with the thread-cells or nematocysts
of the Ccelenterata. Length of body 1-700". HAB. — Salt water : Baltic Sea.

As demonstrated by Bergh, the members of the genus Polykrikos must be referred
to the Cilio-flagellate order of the Infusoria, their distinction from the more ordinary
Peridiniidse consisting only in the greater numerical development of the equatorial
ciliary girdles. The so-called seta issuing from the oral region, as interpreted by
Biitschli, is distinctly proved to be an elongate flagellum, the thickened basal region
only of which appendage was recognized by the last-named authority. The apparent
second seta developed near the first, as reported by Biitschli, of Polykrikos Schwartzii
(see Vol. I. p. 508 and PI. XXVII. Fig. 8), not improbably represents the basal region
of a second flagellum, developed as a preliminary to the phenomenon of transverse
fission. Polykrikos auricularia differs from the last-named type in its more minute
dimensions, in the smaller number of ciliary girdles, these never exceeding eight,
and four being the number of the subdivided zooids, in the larger number of
endoplasts, and in the pinkish hue of its endoplasmic substance. The so-called
trichocysts, irregular in both number and position, reported of this species also by
Bergh, agree precisely with the nematocysts of the Ccelenterata, and are most
probably incepted with its usual food-material. The fact recorded by its discoverer,
that the vegetable colouring substances chlorophyll and diatomin are never present
in this form, indirectly points to its carnivorous habits, and further substantiates the
author's interpretation of these problematic structures.

CLASS Ciliata.

Benedenia elegans, Fcettinger. — Body elongate subcylindrical, somewhat
enlarged at the anterior extremity; cilia distributed over the entire surface;
muscular fibrillae developed upon a spiral plan throughout the length of the body ;
contractile vesicles not detected ; endoplast band-like or represented by numerous
homogeneous granular rods or spheres, rendered visible only with the assistance of
reagents ; movements complex, either forwards or rotary upon its axis, the body
frequently folded upon itself. Multiplying by segmentation, a portion towards the
hinder extremity of the body becoming first separated by a transverse groove, which
is again divided into as many as eight nodular segments which are detached
separately from the parent. Length 1-25".

HAB. — Endoparasitic within the renal organs of the Cephalopod Sepia elegans.

This type, which is referred by Fcettinger to the Opalinidae,* would appear in
many respects to resemble the Termite parasite Dinenympha gracilis of Leidy, de-
scribed and figured at p. 555 and PI. XXVIII. Figs. 21-24. A second species, having
a more marked development of the cilia in the anterior region, inhabiting the renal
organs of the common Octopus, Octopus vulgaris, receives from the same authority
the name of Benedenia coronata. An ovoid Infusorium without mouth or digestive
tube, having a similar holotrichous plan of ciliation, a distinct layer of muscular
fibrillae below the surface of the cuticle, length about 1-250", and inhabiting the
liver of Sepiola rondeletii, is distinguished by M. Fcettinger by the title of Opalinopsis
sepiola, and a very similar type, derived from the liver of Octopus tetracirrhus, as
Opalinopsis octopi.

Chilodon propellens, Engelmann.f — Closely allied to C. cucullulus, but of
more slender form and with a rounded posterior extremity ; swims in circling paths ;

* ' Bull. Acad. Royal Belgique,' and 'Archives de Biologic,' Band ii., 1881.
t Notice in 'Nature,' p. 303, July 24th, 1879.

APPENDIX. 86 1

the contractile vesicle contracts quickly every thirty seconds and gives an impulsive
acceleration of the forward motion, or if at rest, causes at systole a forward movement
of the body for one-quarter of its length.

Stentor amethystinus, Leidy.* — Body trumpet-shaped when extended, oval
when contracted, somewhat resembling S. igneus, existing in attached groups ; endo-
plasm containing an abundance of chlorophyll, but the exterior structure invariably
of a distinct lilac or amethystine colour ; endoplast ovate. Length, when extended,
1-40." HAB. — Fresh water.

The larger size of this animalcule serves to distinguish it from Stentor igneus,
which is also reported by Stein to sometimes assume a brownish or lilac-coloured in
place of the more normal scarlet hue.

Sparotricha vexillifer, Entz. — This title is bestowed by Entzf on a form
obtained by him from the salt-pans of Hungary, and which he describes as differing
from its near ally Stichotricha in the circumstances that the peristomal cilia are
disposed in a continuous banner-like series, in the irregularity of the arrangement
of the other cilia, and in its incapacity to rapidly change its form. The absence of
frontal styles distinguishes it, on the other hand, from the genus Uroleptus. Two
other new forms, Litonotus grandis and Ervilia salina, were obtained by Entz
from the same locality, but the author has not so far been able to obtain access to
their original description.

Drepanostomum pectinatum, Ehr. — This proposed new generic and specific
type is very vaguely described by Ehrenberg J as most nearly resembling Vaginicola,
but having in place of the ordinary ciliary disk a slender flattened anterior process,
the two extremities of which bear vibratile cilia, the chamber-like centre, presumably
the pharyngeal cleft, being also ciliate.

Opercularia arenicola, Greef.§ — Colony-stock usually consisting of two zooids
only, which are situated close to each other at the extremity of a very short stiff
pedicle ; bodies oval, pointed at the extremities ; the peristome and ciliary disk very
narrow; endoplast cord-like. Length of bodies 1-300". HAB. — Bog water.

GENUS Arachnella, S. K. Dim. of Gr. arachne, spider. — Here substituted by
the author in place of Arachnidium, Vol. II. p. 637, preoccupied by T. H. Hincks
('Ann. Nat. Hist.,' Sept. 1877) for the distinction of a genus of Polyzoa.

Pulsatella convolutse, Geddes. — The foregoing title is conferred by Mr. Patrick
Geddes|[ on some curious cells, apparently independent organisms, observed by
him to occur in large quantities within the mesoderm of the marine Planarian
Convoluta Schuhii. The cells are a little smaller than the red blood-corpuscles of
the frog, are nearly in the form of a slightly curved pear, and have a large central
vacuole filled with fluid. On the wall of this cavity and towards the more convex
side of the cell, almost parallel with its principal axis, there is a row of homoge-
neous transparent fibrillae, which are inserted at their upper and lower extremities in
the ordinary protoplasm of which the other parts of the cell is composed. If these
cells are examined free in sea-water, it is seen that they are in a state of rhythmical
contraction, the rapidity and vigour of which are equally surprising, the most active
pulsating from 100 to 180 times per minute ; each time the principal axis becomes
more strongly curved and the cell shorter and broader. This change of form
depends exclusively on the contraction of the inner fibres, the other parts of the
cell remaining quite passive. The movements of the cell soon begin to slacken,
become irregular and feeble, finally cease, and the cell bursts. Its protoplasm soon
perishes, but the fibres resist for a longer time the action of the water, and even

* ' Proc. Acad. Nat. Sci. Philadelphia.' 1880.

t " Ueber einige Infusorien des Salzteiches zu Szamosfalva." ' Termeszetrazii fiizetek,' vol. iii.
219.

\ 'Bonplandia,' 1861.

§ " Protozoenfauna der Moos," ' Marburger Sitzungsbericht,' S. 22, 1873.
|| 'Comptes Rendus,' xciii. (iS8i) ; also Abstract in 'Journ. Roy. Micr. Soc.,' April 1882.

862 APPENDIX.

exhibit a trace of contractility like dying cilia. Numerous observations have con-
vinced Mr. Geddes that these cells are really parasites. Other species of Planarians
yield nothing like them. The delicacy of their protoplasm distinguishes them from
the true tissue of the Convoluta. Moreover, they do not form tissue, and have no
definite disposition. Regarded as parasites, their structure, apparently so abnormal,
is readily derived from the type of ordinary Infusoria by the suppression of the cilia,
which would not be available for locomotion among the cells of the mesoderm, and
the differentiation of the contractile vesicle. This differentiation of the vacuole is
remarkable with reference to its relative enormous proportions, the development of
contractile fibres which limit it, and the rapidity of its contraction. Being altogether
distinct from the ordinary Flagellate, Ciliate, and Suctorial (Tentaculiferous) sections
of the Infusoria, its discoverer proposed to establish a new sub-class, the Pulsatoria,
for its reception.

GENERAL HISTOLOGY AND PHYSIOLOGY.

Fertilization of Seaweeds by Infusoria.

The very interesting discovery has been made by Dr. Dodel-Port, of Zurich,* that
Infusoria, Vorticellae, are instrumental to a large extent in the fertilization of certain
Floridaceous Algae. In Polysiphonia subulata the antherozoids, produced from
antheridia on separate plants, are of a simple spheroidal form and possess no cilia
or other locomotive organs. Their union with the reproductive structures or carpo-
gonia of the female plants, which would be otherwise very hazardous, is greatly
facilitated by the usual presence upon the fruit-bearing branches of numerous
Vorticellae. The characteristic ciliary currents produced by these animalcules attract
the antherozoids floating in the neighbourhood, and cause some one or more to
strike upon and adhere to the trichogyne or slender tubular hair which is produced
from the distal region of the carpogonium, and which subserves the purpose of the
pistil in an ordinary flowering plant. In this manner fertilization is effected by a
process closely analogous to what obtains among the wind-fertilized or so-called
" anemophilous " dioecious phanerogams.

Muscle or Nerve-fibres in Stylonychia mytilus.

T. W. Engelmann "f remarks of the above-named Infusorian that it unquestion-
ably possesses a system of ventral fibres trending from near the middle line, beneath
the ectoplasm, to the two conspicuous series of large admarginal cilia which so
powerfully aid in the motions of this animalcule. These fibres are not like the
fibres of ordinary ciliated cells, nor are the lashes which they supply cilia properly
so called. The lashes (cirri) are complex appendages remote from one another,
moving independently under the control of their possessor. Each has its own fibre,
which is pale, soft, and homogeneous. The fibres are parallel, and so delicate that
they can only be seen for a short time in specimens starved during some hours in
filtered water and then killed in osmic acid. Their interpretation as true nerve-
fibres is favourably entertained by Engelmann.

Method for Colouring Infusoria during Life.

M. A. Certes J finds that Infusoria placed in a weak solution of chinolin or
cyanine — proportion from i to 500,000 and not exceeding i to 100,000 of ordinary
filtered water — are coloured a pale blue, and may continue to live for as long as
thirty-six hours. The coloration is concentrated round the fat-granules of the
protoplasm, but affects feebly or leaves altogether untouched the cilia, cuticle,
nucleus, nucleolus, and vacuoles. The colour disappears on long exposure to light
or if the objects are mounted in glycerine.

* 'Kosmos,' 1879; also 'Nature,' No. 515, Sept. n, 1879.
t " Pfliiger's Archiv Physiologic," Bd. xxiii., 1880.
j 'Comptes Rendus,' xci., 1881.

APPENDIX. 863

Glycogen in Infusoria.

Glycogen, or animal starch, having been demonstrated by M. Claude Bernard
to be present as a product of nutrition in all higher animals, M. Certes * success-
fully experimented with a view to its detection in Infusoria. Under the reaction of
iodine it is revealed by the wine-red, purplish, or mahogany-red colour exhibited by
the component elements of the tissues that contain it. The action of the reagent
being regulated, it was found to be abundantly developed among the Infusoria, it
imparting to the various specimens examined the characteristic tints to the sarcode
element generally, but sparing the cuticle, vibratile cilia, nuclei, nucleoli, and con-
tractile vesicle ; and also, in the case of Vorticella, the contractile filament.

Preservative Fluid for Infusoria. <&c.

Dr. T. F. Allenf finds the following solution suited to the permanent preservation
of Infusoria : —

Wood vinegar, sp. gr. 1*04 ICO parts.

Salicylic acid I part.

The above compound he calls salicylic vinegar; to this add for salicylic
vinegar i part, glycerine 10 parts, and water 40 parts.

* 'Comptes Rendus,' xc., p. 77, 1880.

t 'American Monthly Microscopical Journal,'

p. 98, 1881 ; also 'Journ. Roy. Mic. Soc.,'
October 1881.

GLOSSARY

OF TECHNICAL TERMS EMPLOYED IN THIS TREATISE.

ABIOGENESIS. Gr. a, without ; bios, life. The doctrine of de novo or spontaneous
generation, assuming that living bodies may be evolved from inorganic matter without
the interposition of a parent.

ACETABULIFORM. Lat. acetabulum, a cup or sucker ; forma, form. Having a cup- or
sucker-shaped outline.

ADORAL. Lat. ad, to ; os, arts, the mouth. The fringe of cilia conducting to the oral

aperture of many Infusoria.

AFFERENT. Lat. ad, to ; fero, I carry. Conveying from the surface towards the centre.
AMCEBIFORM. Amceba ; forma, shape. Resembling an Amoeba.
AMORPHOUS. Gr. a, without ; morphe, shape. Having no definite form or structure.

AMPHIBLASTULA. Gr. amphi, on both sides ; blastos, germ. Term proposed by Haeckel
for that modification of the so-called ciliated sponge-larva in which its respective
poles are composed of dissimilar cellular elements.

AMPULLACEOUS-SACS. Lat. ampulla, a bottle. Name applied by Mr. Carter to the
hollow ciliated or monad-lined chambers of many sponges.

AMYLACEOUS. Gr. amulon, starch. Having a starch-like consistence.

ANALOGOUS. Gr. ana, similar to ; logos, ratio. Applied to parts performing similar func-
tions but having a different nature, as the wing of a bird and the wing of a butterfly.

ANTHEROZOIDS. Gr. anthos, a flower ; zoon, an animal. The flagelliferous locomotive
elements in cryptogamic plants which are the homologues of the spermatozoa of
animals.

ARCHEGASTRULA (Haeckel). Gr. arche, beginning ; gastrula. Hypothetical primaeval
gastrula-like organism (see GASTRULA), out of which, by the process of evolution, the
entire Metazoic animal series is supposed to have been gradually developed. Such
an architype Haeckel announced the discovery of in the genus Haliphysema, vol. i.
p. 1 60 et seq.

ARCHENTERON. Gr. archos, chief ; enter on, intestine. The primitive alimentary tract as
developed in the Metazoic embryo.

ARCHITYPE. Gr. arche, beginning ; tupos, image. The original or ancestral type of a
race or species.

ATROPHIED. Gr. a, without ; trophe, nourishment. A condition of being wasted away
through defective nourishment.

BACILLAR. Lat. bacillum, a small staff or rod. Having a rod- or staff-like contour.

BIFLAGELLATE. Lat. bis, twice ; flagellum, whip. Having two whip-like appendages or
flagella.

BILABIATE. Lat. bis, double ; labium, lip. Having the appearance of possessing two
lips.

BIOGENESIS. Gr. bios, life ; genesis, origin. The doctrine that all life springs from
antecedent life.

VOL. II. 2 D

866 GLOSSARY OF TECHNICAL TERMS.

BlOGENETIC. Gr. bios, life ; genesis, origin. Relating to the doctrine that all life springs
from antecedent life, in contradistinction to A biogenesis or de novo generation.

BIOPLASM. Gr. bios, life ; plasma, what is formed. The essential vital element of all
organic bodies, equivalent to Protoplasm.

BLASTOMERE. Gr. blaston, a germ; meros, a portion. The areas delimited by the
segmentation of the ovum.

BUCCAL. Lat. bucca, the mouth. Relating to the mouth or oral aperture.
CAMPANULATE. Lat. campanula, a little bell. Having the shape of a bell.

CANCELLATE. Lat. cancelli, a lattice or grating. Having an open network- or lattice-like
structure.

CARAPACE. Gr. karabos, a crustaceous animal. The indurated dorsal shield possessed
by such infusorial forms as Euplotes and Aspidisca.

CAPILLITIUM. Lat. capillitiTim, the hair collectively. The thread or hair-like filaments
developed within the spore-capsules or sporangia of certain Mycetozoa.

CAPITULUM. Lat. capitulum, a little head. Term applied to the stalked spheroidal
spore-receptacles or sporangia of certain Mycetozoa.

CATACLYSMIC. Gr. kataklysmos, an inundation, deluge. Having reference to sudden

and abnormal alterations of the conditions of the universe, such as by a deluge or an

earthquake.
CHITINOUS. Gr. chiton, a coat of mail. Corresponding in nature with chitine or the

horny material which forms the protective covering and skeletal elements of Insects

and other Arthropoda.
CHLOROPHYLL. Gr. chloros, grass-green ; phullon, a leaf. The green colouring-matter

of vegetable organisms.
CHLOROPHYLL ACEOUS. Having the nature of chlorophyll.

CILIA, Lat. cilium, an eyelash. The fine hair-like appendages that constitute the
locomotive organs of a large group of Infusoria and many lower animals.

CIRRI. Lat. cirrus, a lock of hair. The elongate, flattened modifications of ordinary
cilia, developed upon the peristomal region of many Ciliate Infusoria.

CLOACA. Lat. cloaca, a common sewer. The common cavity upon which the interstitial

canal-systems of a sponge body open, and are thence discharged into the surrounding

water.
CCENOBIUM. Gr. koinos, common ; bios, life. Term applied by Stein to the spherical

monad clusters developed at the terminations of the branching pedicle of such a type

as Anthophysa.

COMMENSAL. Lat. cum, together ; mensa, table, board. Term applied by Van Beneden
to those pseudoparasitic organisms which do not live at the expense of the organisms
to which they are usually attached, but are associated with them simply as comrades
or messmates.

COMMENSALISM. Lat. cum, together ; mensa, table, board. The state of existence as a
commensal.

CONJUGATION. Lat. conjugo, to unite. The temporary or permanent growing together
of two or more infusorial bodies, such union conducing to reproduction by germs or
spores or to the renewal of their capacity to multiply by simple fission.

CONVOLUTE. Lat. con, together ; -volutus, rolled. Rolled upon itself.
CORTICAL. Lat. cortex, bark. Relating to the bark or external layer of an organism.
CRATERIFORM. Lat. cratera, a cup ; forma, form. Having the shape of a cup.
CRENULATE. Dim. of Lat. crena, notch. Finely notched or serrated.

GLOSSARY OF TECHNICAL TERMS. 867

CUIRASS. Fr. from cuirt leather. An indurated defensive shield, synonymous with
Carapace.

CUTICULUM. Lat. cuticula, a little skin. The more indurated pellicle which forms the
outer layer of the body of Infusoria.

CYCLOSIS. Gr. kuklosis, a moving round. The protoplasmic circulation observable in
the cells of certain plants, and also in many Protozoic organisms such as within the
body of Paramcecium bursaria and the pseudopodia of the Foraminifera.

CYTOBLASTEMA. Gr. kutos, a cell ; blastano, I bud. The viscid fluid in which animal
and vegetable cells are produced. Here applied to the glairy structureless matrix in
which the collared and amcebiform cells of the sponge-body are immersed and
generated.

CYTOBLASTS. Gr. kutos, a cell ; blastano, I bud. The amcebiform cells immersed and
generated within the hyaline matrix or cytoblastema of a sponge-body.

CYTODES. Gr. kutos, a cell, A term applied by Haeckel to unicellular organisms or
elements, that have the value of a simple cell but possess no distinct nucleus.

CYTOPYGE. Gr. kutos, cell ; puge, the rump. A term introduced by Haeckel for the
distinction of the so-called excretory or anal aperture of unicellular animals.

CYTOSTOME. Gr. kutos, cell ; stoma, a mouth. A term proposed by Haeckel for the dis-
tinction of the so-called oral aperture of unicellular animals.

DACTYLOZOOIDS. Gr. daktulos, a finger; zoon, animal. Term proposed by H. N.

Mosely for the distinction of the attenuate mouthless zooids developed by Millepora,

Stylaster, and other coral-building Hydrozoa.
DIAPHANOUS. Gr. dia, through ; phaino, I show. Transparent, permitting the passage

of light.
DIASTOLE. Gr. diastello, to dilate. A term expressive of the expanding action of the

contractile vesicle of Infusoria and other Protozoa.
DIATOMIN. Gr. diatemno, to separate. A term applied to the essential brown colouring

matter of the vegetable organisms known as Diatoms.
DICHOTOMOUS. Gr. dicha, in two parts ; tome, a cutting. Having the divisions of its

substance arranged in pairs ; furcate or forked.

DECURRENT. Lat. de, down ; currens, running. Running out or projecting beyond.
DIFFERENTIATED. Lat. differo, I separate. Applied to an organic body or structure

which exhibits a distinct separation into diverse elementary components.
DIFFLUENCE. Lat. diffluens, dissolving. A term introduced by Dujardin to indicate that

peculiar phenomenon of dissolution exhibited by many Infusoria, in which the sarcode

substance of their bodies as it were gradually melts away.

DICECIOUS. Gr. dis, double ; oikos, a house. Having the male and female sexes repre-
sented in two distinct individuals.
DIPLOBLASTIC. Gr. diploos, double ; blastos, germ. Relating to that condition of the

Metazoic embryo in which two germinal cellular layers are distinctly represented.
DEXTROGYROUS. Lat. dextra, the right hand; gyros, a circle. Circling towards the

right.
DEXTROTROPOUS. Lat. dexter, to the right ; Gr. trope, a turning. Turning to the

right.
ECTODERM. Gr. ektos, outside ; derma, skin. The external ^f thV two germinal cellular

layers, common to all multicellular or Metazoic animal organisms, out of which are

developed the protective and sensory elements, including the skin, cuticle, nervous

system, and organs of special sense.
ECTOPARASITIC. Gr. ektos, outside; parasitos, parasite. Having the nature of an

external parasite.

2 D 2

868 GLOSSARY OF TECHNICAL TERMS.

ECTOPLASM. Gr. ectos, outside ; plasma, that which is formed. A term applied by the
author for the distinction of the denser external substance of Infusoria and other
unicellular organisms.

EFFERENT. Lat. ex, out ; fero, I bear. Conveying from the'centre towards the periphery.
EMARGINATE. Lat. e, out of; margo, the margin. Having a notched or excised margin.
ENCUIRASSED. Fr. en, in ; cuir, leather. Having an indurated dorsal shield or cuirass.

ENCYSTMENT. Gr. en, in ; kustos, a bladder. The phenomenon of becoming motionless
and excreting a membranous investment or cyst, common to the majority of the
Infusoria.

ENDOCHROME. Gr. endon, within; chroma, colour. The colouring matter developed
within the interior of many Protozoa and Protophytes.

ENDODERM. Gr. endon, within ; derma, skin. The interior of the two germinal cellular
layers common to ah1 multicellular or Metazoic animal organisms, out of which are
developed the digestive and secretory systems, including the epithelium which lines the
alimentary tract and its connected glands.

ENDOPARASITIC. Gr. endon, within ; parasites, parasite. Pertaining to an internal
parasite.

ENDOPLASM. Gr. endon, within ; plasma, that which is formed. A term applied by the
author for the distinction of the inner more fluid substance of the body of Infusoria
and other unicellular organisms.

ENDOPLAST. Gr. endon, within ; plastos, formed or moulded. Title conferred by Huxley
on the structure homologous with the cell-nucleus as developed in the Infusoria
and other Protozoa. For an account and illustration of the more important modifica-
tions of this structure see vol. i. p. 73 et seq. and PI. L.

ENDOPLASTULE. Gr. endon, within ; plastos, formed. Title applied by Huxley to the
more solid particles developed singly or in varying number within, or in many cases
external to, the endoplast of Protozoic organisms, the same being regarded as
homologous with the nucleoli of the component cells of ordinary tissue structures.

ENDORAL. Gr. endon, within ; Lat. os, oris, mouth. The fringe of cilia developed

between the adoral and pre-oral series of certain Oxytrichidae (see woodcut, vol. ii.

p. 760).
ENDOSKELETAL. Gr. endon, within ; skeleton. Relating to the internal skeleton ; such as

the bony human framework.
EPIBLAST. Gr. epi, upon ; blastos, germ. The external or outer germinal layer of the

Metazoic embryo, equivalent to the Ectoderm.

EPITHELIUM. Gr. epi, upon ; thallo, I grow. The layer of cells being a modification of
the epidermis which forms the surface of all mucous membranes.

EXOSKELETAL. Gr. exo, outside; skeleton. Relating to an external skeleton, such as

the shell of a lobster.

EVERTED. Lat. eversio, a turning out. The condition of being turned out or backwards.
EVERTILE. Lat. eversio, a turning out. Capable of eversion or protrusion.
FENESTRATE. Lat. fenestra, a window. Having holes or perforations.

Fl BRILLS. Lat. dim. otjibra, a fibre. The delicate thread-like structures developed in
the cortical layer of many Infusoria, as also in the footstalk of Vorticella, and possessing
a rudimentary muscular function.

FIBRILLATE. Lat. dim. otjibra, a fibre. Containing or enclosing fibrillae.

FIMBRIATED. Lat. fimbrice, threads or fringe. Fringed at the margin.

FLAGELLIFEROUS. Lat. flagellum, a whip or lash ; fero, I bear. Bearing one or more
flagella or lash-like appendages.

GLOSSARY OF TECHNICAL TERMS. 869

FUNICULUS. Lat. funiculus, a little cord. A term here applied to the slender thread-
like filament which connects the component nuclear masses in such infusorial types
as Loxodes and Loxophyllum.

GASTRCEA or GASTRULA. Dim. Gr. gaster, a belly. That stage of the embryo in
various animals in which it consists of two fundamental cellular membranes, ectoderm
and endoderm, enclosing a central cavity.

GASTROZOOIDS. Gr. gaster, the belly ; zoon, animal. Title proposed by H. N. Mosely
for the distinction of the ordinary alimentative or mouth-bearing zooids of Millepora,
Stylaster, and other coral-building Hydrozoa.

GIBBOUS. Lat. gibbus, hunchbacked. Unsymmetrically distended or swollen at some part

of the surface.
GLABROUS. Lat. glaber, smooth. Having a smooth surface.

GUBERNACULUM. Lat. g ubernaculum, a helm or rudder. A title utilized by H. James-
Clark for the distinction of the trailing flagellum, having an apparent guiding function,
developed in such infusorial forms as Anisonema and Heteromita.

HELICOIDAL. Gr. helix, a spiral ; eidos, resemblance. Having a twisted or spiral
contour, like a snail-shell.

HETEROGENEOUS. Gr. heteros, different ; genos, kind. Having a mixed or compound
constitution, the converse of Homogeneous.

HETEROGENY. Gr. heteros, different ; genos, birth. The doctrine maintaining that
living organisms are produced out of inorganic matter ; identical with Abiogenesis.

HETEROTRICHOUS. Gr. heteros, different; thrix, hair. Having hair or cilia of diverse
character.

HISTOLOGY. Gr. histos, a web or tissue ; logos, discourse. The study of the more
minute or cellular elements of organic structures.

HOLOTRICHOUS. Gr. holos, whole; thrix, hair. Having hair or cilia of a uniform
character developed over the entire surface.

HOMOGENEOUS. Gr. homos, same ; genos, kind. Having a simple or uniform constitution,
in contradistinction to Heterogeneous.

HOMOLOGOUS. Gr. homos, same ; logos, expression. Having the same morphologic or -
structural value, though possibly differing in form and function, as the arm of a man
and the wing of a bird.

HOMOPLASTIC. Gr. homos, same ; plastikos, moulded or formed. Having a similar
or corresponding form.

HOMOPLASTS. Gr. homos, same ; plastikos, what has been formed. Objects corresponding
in external form though of a distinct nature.

HYPOBLAST. Gr. hupo, under ; blastos, germ. The internal germinal layer of the
Metazoic embryo, equivalent to the Endoderm.

HYPOTRICHOUS. Gr. hupo, under ; thrix, hair. Having hair or cilia developed only on
the under surface.

ILLORICATE. Lat. //for in, not, without; lorica, coat of mail. Devoid of a protective
sheath or lorica.

INDURATED. Lat. induratus, hardened. Having a hardened consistence.
INFUNDIBULIFORM. Lat. infundibulum, a funnel ; forma, shape. Funnel-shaped.

INTERSTITIAL. Lat. inter, between; sisto, I stand. Relating to intervening parts or
spaces.

ISOMORPHIC. Gr. isos, equal ; morphe, shape. Exhibiting an equal or corresponding
contour.

870 • GLOSSARY OF TECHNICAL TERMS.

KERATOSE. Gr. keras, a horn. The fibrous horn-like material out of which the skeletal

elements of many sponge-forms are constructed.

LjEOTROPOUS. Gr. laia, left ; trope, a turning. Turning to the left.
LIGULATE. Lat. ligula, a little tongue or strap. Having a strap-shaped contour.

LORICA. Lat. lorica, a coat of mail. The organically distinct protective sheath or
domicile, excreted and inhabited by many Infusoria such as Vaginicola, Tintinnus,
and Salpingoeca.

MACROSPORES. Gr. macros, long ; spora, seed, The spore-like elements, few in number
but of relatively large size, into which the bodies of many monads become sub-
divided.

MASTIGOPODA. Gr. mastix, a whip ; pous, a foot. A term conferred by Huxley on all
those Protozoa which possess cilia or flagella, and thus embracing the two Infusorial
Classes of the Ciliata and Flagellata as delimited in this treatise.

MEMBRANELL^E. Lat. dim. of membrana, membrane. A term proposed by Sterki for
the distinction of the relatively large flattened cilia that constitute the peristomal
fringe in many Ciliate Infusoria, synonymous with Cirri.

MESOBLAST. Gr. mesas, middle ; blastos, germ. The middle germinal layer of the

Metazoic embryo, equivalent with the Mesoderm.
MESODERM. Gr. mesos, middle ; derma, skin. The middle germinal layer developed in

all forms more highly organized than the Ccelenterata, and out of which are chiefly

developed the general connective tissue, internal skeleton, the muscular system, the

lining of the body-cavity, the vascular and excretory systems.

METABOLIC. Gr. meta, change; hallo, I throw. Changeable in form; applied by Cohn
to the Infusoria in the same sense as polymorphic.

METAMORPHIG. Gr. meta, change ; morphe, shape. Changeable in form.

METAZOA. Gr. meta, change, beyond ; zoon, animal. Term applied to all those animals
above the Protozoa, which in the course of their development undergo certain
metamorphoses, consisting of the primary segmentation of a true egg or ovum, and
subsequent passage through an embryonic condition in which they possess two
distinct germinal cellular layers.

METAZOIC. Gr. meta, change ; zoon, animal. Relating to the Metazoa.

MICROSPORES. Gr. mikros, small ; spora, seed. The spore-like elements, of exceedingly
minute size but very numerous, produced through the encystment and subsequent
subdivision of many monads.

MICROZOOIDS. Gr. mikros, small ; zoon, animal. Title here conferred upon the free-
swimming zooids of abnormally minute size, which conjugate with or become buried
within the substance of the bodies of the normally sized sedentary animalcules of
many Vorticellidae.

MENISCOIDAL. Gr. meniskos, a little moon ; eidos, resemblance. Having a lens-shaped
or watch-glass-like contour, convex on the one side and concave on the other.

MOLECULAR. Fr. molecule, a small particle of matter ; from Lat. moles, mass. Relating

to the ultimate quantitative elements of an organic body.

MONADIFORM. Monad ; forma, shape. Having the aspect of a simple monad.
MONADIGEROUS-LAYER. Monad; gero, I bear. Applied by H, James-Clark to that

stratum in the sponge-structure which is chiefly composed of monadiform elements.

MONILIFORM. Lat. monile, a necklace ; forma, shape. Jointed so as to resemble a string
of beads.

MONOBLASTIC. Gr. monos, single ; blastos, germ. Relating to that condition of the
Metazoic embryo, immediately succeeding segmentation, in which a single germinal
layer is alone represented.

GLOSSARY OF TECHNICAL TERMS. 871

MONOECIOUS. Gr. monos, single; oikos, house. Having the male and female sexes

represented in a single individual.
MONOFLAGELLATE. Gr. monos, alone ; flagellum. Bearing a single flagellum only.

MORULA. Lat. dim of morum, a mulberry. That stage of the ovum when, after segmen-
tation, it is represented by a berry-like spheroidal mass of nucleated cells.

MORULOID. Having the character of a Morrtla.

MORPHOLOGICAL. Gr. morphe, shape ; logos, description. Having relation to the

general structure of organic forms whether animals or plants.
MULTICAPITATE. Lat. multus, many ; capitatus, having a head. Having many heads.

MULTIFLAGELLATE. Lat. multus, many ; flagellum, whip. Possessing many flagella or
whip-like appendages.

MULTINUCLEATE. Lat. multus, many ; nucleus, a kernel. Possessing a plurality of
nuclei, e. g. Opalina.

MYCELIUM. Gr. mukes, a fungus. The aggregation of cellular filaments or hyphae of a
fungus, and from out of which the reproductive structures are developed.

MYOPHAN. Gr. muon, a muscle ; phaino, I show. Term applied by Haeckel to that layer,
developed in many Infusoria, that contains muscle-like fibrillas.

MYXOPODA. Gr. muxa, mucus ; POUS, a foot. Term applied by Huxley to those
Protozoa whose locomotive appendages take the form of pseudopodia, synonymous
with Rhizopoda.

NAPIFORM. Lat. napus, a turnip ; forma, shape. Turnip-shaped.
NUCLEOLAR. Lat. nucleus, a kernel. Having the character of a nucleus.

NUCLEOLUS. Lat. nudeolus, a little kernel. An exceedingly minute more solid particle
developed singly or in varying number within the substance of the nucleus of an
animal or vegetable cell. Its homologue among the unicellular protozoic organisms
is distinguished in this volume by the title of the Endoplastule.

NUCLEUS. Lat. nucleiis, a small nut or kernel. A minute refringent or more densely
granular corpuscle developed within the substance of most animal and vegetable cells,
its homologue in unicellular protozoic organisms being distinguished by the title of
the Endoplast.

(EsOPHAGEAL. Gr. oisophagus, the gullet. Relating to or connected with the oesophagus.

OESOPHAGUS. Gr. oisophagus, the gullet. A distinct gullet or cesophageal tube has been
recognized as existing in certain Vorticellidae.

ONTOGENY. Gr. on, ontos, being ; genos, lineage. The circumstances relating to the
entire developmental metamorphoses or life-history of any individual animal or plant.

OPERCULUM. Lat. operculum, a lid or cover. The lid-like structure developed within
the sheath or lorica, or attached to the body of certain Vorticellidas.

PANICULATE. Lat. panicula, a tuft on plants. That form of inflorescence consisting of
spikelets on long peduncles which are developed in the manner of a raceme.

PANSPERMISTS. Gr. pan, all, everywhere ; sperma, seed. A name conferred upon those
who, in the controversy upon the subject of Spontaneous Generation, advocated the
opinion that invisible germs of Infusoria and other microscopic organisms were dis-
tributed throughout the atmosphere.

PARENCHYMA. Gr. para, together ; encheo, to pour in. The secreting tissue of glands,
also applied to cellular tissue of plants, and (by Stein) to the more fluid internal sub-
stance of Infusoria, synonymous in the last-named case with Endoplasm.

PARORAL. Gr. para, beside ; Lat. os, oris, mouth. The fringe of cilia developed at the
side of the adoral series on certain Oxytrichidac. (See woodcut, vol. ii. p. 760.)

872 GLOSSARY OF TECHNICAL TERMS.

PECTINATE. Lat. pecten, a comb. Divided into narrow segments like the teeth of a
comb.

PEDUNCULATE. Lat. pedunculus, a little foot. Provided with a stalk or pedicle.

PERIDIUM. Gr. perideo, I wrap round. The membranous outer wall of the spore-
capsule or sporangium of the Mycetozoa,

PERISTALTIC. Gr. peristaltikos, drawing together all round. Applied to the circular
contractions from above downwards, exhibited by the intestines, and also in the
locomotion of many worm-like animals.

PERISTOME. Gr. peri, around ; sterna, a mouth. The oral region with its accompany-
ing cilia, as applied to the Infusoria.

PERISTOMAL. Gr. peri, around ; stoma, the mouth. Relating to the peristome or oral
region.

PERITRICHOUS. Gr. peri, around ; thrix, hair. Having hair or cilia developed in the
form of a wreath or girdle round the body.

PHARYNGEAL. Pertaining to or connected with the pharynx.

PHARYNX. Gr. pharunx, the throat or windpipe. As applied to the Infusoria, denoting
that part of the alimentary tract, sometimes with indurated walls, that immediately
succeeds the oral orifice.

PHYCOCHROME. Gr. phukos, sea-weed ; chroma, colour. The essential brown colouring
matter of the olive-tinted or Melanospermous sea- weeds.

PHYLOGENY. Gr. phulon, tribe ; genos, lineage. That branch of biology which attempts
to deduce the ancestral history of an animal or plant from its ontogeny or individual
developmental metamorphoses.

PHYLUM. Gr. phulon, tribe. Stock or tribe.

PHYTOPHAGOUS. Gr. phuton, a plant ; phago, I eat. Feeding upon plants.

PLANULA. Lat. planula, a little plane. The flattened, mouthless, ciliated embryo of
many Coelenterata.

PLASMODIUM. Gr. plasma, a thing moulded ; eidos, resemblance. The gelatinous proto-
plasmic mass, possessing distinct locomotive properties, formed by the coalescence of
the flagelliferous monadiform elements of the Myxomycetes or Mycetozoa.

PLASTICS. Gr. plastos, formed. A term occasionally applied to unicellular organisms or
elements that possess the value of a simple cell.

PLICATE. \^2&..plicatus, folded. Disposed in pleats or folds.

POLYMORPHIC. Gr. polys, many ; morphe, shape. Exhibiting a diversity of outline, e.g.
Euglena.

POLYTHECIUM. Gr. polys, many ; theke, a sheath or case. Title conferred by the
author on the compound structure, consisting of many conjoint sheaths or loricse,
developed by such infusorial types as Dinobryon and Stylobryon.

PREORAL. Lat. pra, before ; os, oris, mouth. The fringe of cilia developed in front
of the mouth of certain Oxytrichidae. (See woodcut, vol. ii. p. 760.)

PROBOSCIDIFORM. Lat. proboscis, a trunk ; forma, form. Having a trunk-like aspect.

PROGLOTTIDS. Gr. pro, before ; glottis, the opening into the windpipe. The detached
sexually mature segments of a tape-worm, Tcenia.

PROTEINACEOUS. Gr. protos, first. Having a composition analogous to or containing
Protein.

PROTEIN. Gr. protos, first. A nitrogenous substance analogous to fibrin, manufactured
by plants out of inorganic compounds, and upon which all animals are dependent for
food, and for the sustentation of their vital functions.

GLOSSARY OF TECHNICAL TERMS. 873

PROTOPHYTES. Gr. protos, first ; phuton, a plant. Organisms lowest in the scale of
the vegetable kingdom, having an essentially unicellular composition.

PROTOPLASM. Gr. protos, first ; plasma, what has been formed. The physical basis of
life, or elementary formative matter of all organic tissues.

PROTOZOA. Gr. protos, first ; zoon, animal. The simplest, unicellar, animals.

PSEUDOPODI A. Gr. pseudes, false ; podes, feet. Prolongations of the sarcode substance
of the body of Rhizopods and other Protozoa, which subserve the purpose of locomo-
tive appendages or feet.

PULSELLUM. 'La.i. propello, pulsum, to push or drive. Term conferred by Ray Lan-
kester on that modified form of flagellum chiefly characteristic of Spermatozoa, but
possessed by some few flagellate Infusoria, whose action serves to drive the body
backwards through the water.

RACEMOSE. Lat. racemus, the stalk of a cluster of grapes. Having a clustered form of
growth, like grapes.

RENIFORM. Lat. rents, a kidney ; forma, shape. Shaped like a kidney.

REVOLUTE. Lat. re, back ; volvo, I roll. Rolled back upon itself.

RHIZOPODA. Gr. rhiza, root ; pous, a foot. That group of the Protozoa whose loco-
motive organs take the form of extensile root-like processes, or pseudopodia.

RHYTHMICAL. Gr. rhuthmos, measured motion. Denoting the regular pulsations of an
organ such as the contractile vesicle of an Infusorium.

ROTULATE. Lat. rotula, a wheel. Wheel-shaped.

SARCODE. Gr. sarx, flesh ; eidos, resemblance. The simple glutinous matter which
constitutes the chief body or vital mass of all Protozoa.

SARCOLEMMA. Gr. sarx, flesh ; lemma, skin. The delicate investing membrane of

muscular fibre.
SET^E. Lat. seta, a stiff hair or bristle. The stouter bristle-like cilia possessed more

abundantly by the Hypotrichous order of the Ciliate Infusoria.
SHAGREENED. Fr. chagrin, skin of a shark. Having a roughened consistence like

shark-skin.
SIGMOIDAL. Gr. letter s ; eidos, resemblance. Having a shape resembling the letter S.

SILICIOUS. Lat. stlex, flint. Partaking of the nature and qualities of silica ; composed

of flint.
" SOIE DE LACHMANN." Name conferred by Claparede upon the oral seta of the Vorti-

cellidae, here distinguished as the vestibular seta.

SPATULATE. Lat. spatula, a broad blade or slice. Having a broad blade-shaped

outline.
SPORANGIUM. Gr. spora, seed ; anggos, vessel. The spore-capsule or spore-receptacle

of the Mycetozoa.

SPORIPAROUS. Gr. spora, seed or spore ; pario, I produce. Producing spores.
STOLON. Lat. stolon, a lax trailing branch. The procumbent adherent basal region of

the colony-stock of such a type as Dendrosoma.
SWARM-GEMMULE. Name applied by the author, Vol. i. p. 183, to the so-called ciliated

sponge-larvae, and maintained by him to represent not individual germs or larvae, but

ovate aggregations of typical collared monads.

STYLATE. Gr. stulos, a pen. Having a pointed stalk, or style-like character.

SYNCYTIUM. Gr. sun, together ; kutos, cell. Term applied by Haeckel to the hypothetic
ectodermal layer of a sponge, and in which, according to his interpretation, the cells
are indistinguishably fused with one another, their respective nuclei alone being
visible. Such a potential, though unsubstantial, multicellular structure is most nearly
realized in the Opalina and other multinucleate Infusoria.

874 GLOSSARY OF TECHNICAL TERMS.

SYSTOLE. Gr. sustello, to draw together. A term applied to the contracting action of
the structure known as the contractile vesicle of Infusoria and other Protozoa.

TAXONOMY. Gr. taxis, arrangement ; nomos, law. The systematic statement and gene-
ralization of the facts of morphology, in such a manner as to arrange living beings in
groups, according to their degrees of likeness.

TENTACULIFEROUS. Lat. tentaculum, a tentacle ; fero, I bear. Bearing or possessing
tentacles.

TENTACULIFORM. Lat. tentaculum, a tentacle or feeler; forma, form. Having the

form of a tentacle.
TRABECULJE. Lat. trabecula, a little beam. Connecting rod- or bar-like structures.

TRACTELLUM. Lat. traho, tractum, to draw. Term introduced by Ray Lankester for
the distinction of the anteriorly projected flagellum of ordinary flagellate Infusoria,
whose movements serve to draw the body through the water.

TRICHOCYSTS. Gr. thrix, trichos, hair; kustos, a bladder. Minute rod-like bodies
developed in the cortical layer of many Infusoria.

UNCINI. Lat. uncinus, a hook. The claw-like modification of ordinary cilia possessed
by many hypotrichous ciliate Infusoria.

VACUOLATE. Lat. dim. of vacuus, empty. Having a number of clear spaces or inter-
stices.

VELUM. Lat. velum, a veil Here applied to the delicate veil-like membrane bordering
the oral orifice in such forms as Cyclidium and Pleuronema.

VERMICULAR. Lat. vermiculus, a little worm. Resembling a worm in shape.

VESTIBULUM. Lat. vestibulum, a forecourt. The excavated chamber or fossa into
which both the oral and anal apertures debouch, as developed in the Vorticellidae.

VESTIBULAR-SETA. The bristle-like cilium or seta that projects from the vestibulum or
oral fossa of many Vorticellidae.

ZOOCAULON. Gr. zoon, animal ; caulos, a stem. Title conferred by the author on the
erect tentaculiferous branching colony-stocks of the genus Dendrosoma.

ZOOCYTIUM. Gr. zoon, animal ; kutos, a cell. A term applied by the author to the
gelatinous matrix excreted and inhabited by various colonial Infusoria, such as
Proterospongia, Phalansterium, and Ophrydium.

ZOODENDRIUM. Gr. zoon, animal ; dendron, a tree. A term applied by the author for
the distinction of the dendritic or tree-like colony-stocks of such Infusoria as Dendro-
monas and Epistylis.

ZOOID. Gr. zoon, animal; eidos, shape. An animal organism not independently
developed from a fertilized egg or ovum, but derived from a preceding individual by
the process of fission or gemmation. Specially applicable to the Infusoria and other
Protozoa, and to the component members of all stock-building communities, such as
Polypes, Corals, and Polyzoa.

ZOOSPORES. Gr. zoon, an animal ; spora, seed. The ciliated locomotive germs of Algas

and Protophytes.
ZOOTHECIUM. Gr. zoon, animal ; theca, sheath. A term applied by the author to the

compound tubular structures excreted and inhabited by such colonial Infusoria as

Rhipidodendron and Schizosiphon.

ZYGOSIS. Gr. zugon, a yoke. The genetic union or conjugation of two Infusoria.

ZYMOTIC. Gr. zumotos, fermented. Pertaining to or caused by fermentation. Zymotic
diseases, that large class of contagious diseases supposed, and in many cases proved,
to be caused by the reception into the system of a protophytic virus which acts as
a ferment.

CHRONOLOGICAL LIST

OF THE MORE IMPORTANT WORKS AND PAMPHLETS RELATING TO
THE INFUSORIA PUBLISHED SINCE THEIR FIRST DISCOVERY IN
A.D. 1675 TO THE YEAR 1882.

1677. ANTONY VAN LEEUWENHOEK, Observations concerning little Animals observed in
Rain, Well, Sea, and Snow Water, as also in Water wherein Pepper had lain
infused. ' Philosophical Transactions,' vol. xii. p. 821.

1677. - , Account of the manner of observing- little Animals in divers sorts of Water.

1683. - > Opera Omnia.

1685. - > Onttedingen en Ontdekkingen.

1693. SIR EDMUND KING, Several Observations and Experiments on the Animalcula. in

Pepper-water, &c. ' Philosophical Transactions,' vol. xvi. p. 86 1.

1694. A. VAN LEEUWENHOEK, Concerning Animalcula found in Teeth. ' Philosophical

Transactions,' vol. xvi. p. 646.

1695. - , Arcana Naturae detecta. 4to, Delphis Batavorum.

1696. STEPHEN GRAY, Several Microscopical Observations and Experiments. ' Philo-

sophical Transactions,' vol. xix. No. 221.

1696. JOHN HARRIS (Rector of Winchelsea), Some Microscopical Observations of vast
numbers of Animalcula seen in water. ' Philosophical Transactions,' vol. xix.
p. 254.

1702. A. VAN LEEUWENHOEK, Concerning the Worms in Sheeps' Livers, Gnats, and
Animalcula in the Excrements of Frogs. ' Philosophical Transactions,'
vol. xxii. No. 261.

1702. - , Continuatio Arcanorum Naturae. 4to, Delphis Batavorum.

> Concerning Green Weeds growing in Water, and some Animalcula

found about them. ' Philosophical Transactions,' vol. xxiii. No. 283.

1703. ANONYMOUS, An Extract of nine Letters sent to Sir C. H., relating to some Micro-

scopical Organisms. ' Philosophical Transactions,' vol. xxii. No. 284.

1703. A. VAN LEEUWENHOEK, Observations on some Animalcula in Water; the dis-

solution of silver, &c. ' Philosophical Transactions,' vol. xxiii. No. 286.

1704. - , A letter concerning Animalcula on the roots of Duckweed. ' Philosophical

Transactions,' vol. xxiv. p. 1784.

1708. - , A letter containing some further microscopical observations on the
Animalcula found upon Duckweed. ' Philosophical Transactions, vol. xxviii.
p. 1 60.

1713. - , Further Microscopical Observations on the Animalcules found upon
Duckweed,

1718. LOUIS JOBLOT, Descriptions de Nouveaux Microscopes, avec de nouvelles Observa-
tions faites sur une multitude d'insectes qui naissent dans les liqueurs pre'pare'es.
4to, Paris.

8 76 CHRONOLOGICAL LIST OF WORKS

1722. A. VAN LEEUWENHOEK, Opera Omnia Anatom. et Contempl.

1740. HENRY BAKER, An Account of Leeuwenhoek's Microscopes. ' Philosophical
Transactions,' vol. xli. No. 458.

1742. , The Microscope made Easy. 8vo, London.

I743- •> A Contribution towards the Natural History of the Polype. 8vo, London.

1744. ABRAHAM TREMBLEY, Observations upon several newly discovered Species of

Fresh-water Polypi. ' Philosophical Transactions, vol. xliii. No. 476.

1745. T. NEEDHAM, An Account of some new Microscopical Discoveries. 8vo, London.

1746. UNGER, Ueber Infusorien. ' Gottinger Zeitung von gelehrt. Sachen.'

1748. T. NEEDHAM, Summary of some late Observations upon the Generation, Composi-
tion, and Decomposition of Animal and Vegetable Substances. ' Philosophical
Transactions,' vol. xlv.

1752. JOHN HILL, Essay in Natural History, containing a series of discoveries by the
assistance of Microscopes. 8vo, London.

1752. , History of Animals, including the several classes of Animalcula visible only

by the assistance of the Microscope. Fol., London.

1753. HENRY BAKER, Employment for the Microscope. 8vo, London.

1754. L. JOBLOT, Observations d'Histoire Naturelle faites avec le Microscope sur les

Animalcules qui se trouvent dans les liqueurs pre'pare'es. 4to, Paris.

I754- J- C. SCHAFFER, Die Armpolypen in den siissen Wassern von Regensburg. 4to,
Regensburg.

1755. A. J. ROSEL, Insectenbelustigungen. Th. iii. 4to, Niirnberg.
1758. LINNJEUS, Systema Naturae. Ed. x., 8vo, Bruxelles.

1760. M. T. LEDERMULLER, Mikroskop-Gemiiths- und Augen-Ergotzung. 410,
Niirnberg.

1763. • , Amusement Microscopique tant pour 1'esprit que pour les yeux. 3 vols, 4to,

Niirnberg.

1764. L. SPALLANZANI, Saggio di osservazioni microscopiche. 8vo, Modena.

1765. WlSSBERG, Observations de Animalculis Infusoriis. 8vo, Gottingen.

1766. PALLAS, Elenchus Zoophytorum. 8vo, Hagae Comitis.

1767. LINNAEUS, Systema Naturae. Ed. xii., 8vo, Bruxelles.

1769. JOHN ELLIS, Observations on a particular manner of increase in the Animalcula of
Vegetable Infusions. ' Philosophical Transactions,' vol. lix., p. 138.

1773. O. F. MUELLER, Vermium terrestrium et fluviatilium Historia. 4to, Havnise et

Leipsig.

1774. GOEZE, Bonnet's Abhandlung aus der Insectologie. Bd. ii.

1775- J- C. EICHORN, Beitrage zur Kenntniss der kleinsten Wasserthiere, die mit keinem
blossen Auge nicht konnen gesehen werden. 4to, Danzig.

1776. OTHO FRIEDRICH MUELLER, Zoologiae Danicse Prodromus. 8vo, Havniae.

1777. L. SPALLANZANI, Opuscules de Physique Animaleet Ve'ge'tale. Geneva.

1778. SLABBER, Naturk. Verlustigingen.
1778. BASTER, Naturk. Uitspanningen.

1778. W. F. GLEICHEN, Abhandl. iiber die Saamen u. Infusionsthierchen. 410,

Niirnberg.
1780. SCHRANK, / Neue Philosoph. Abhandl." d. Baierischen Akad. d. Wiss.,' Bd. ii.

p. 479.

RELATING TO THE INFUSORIA. 877

1781. GLEICHEN, Auserlesene Mikrosk. Entdeckung bei den Pflanzen, Blumen,

Inseckten, &c.

1782. BLOCK, Abh. iiber Erzeug. der Eingeweidewurmer.

1782. FONTANA, Wasserthierchen. ' Mem. di matemat. ed fisica del soc. Ital.,' t. L
1782. GOEZE, Naturgeschichte der Eingeweidewurmer.

1786. O. F. MUELLER, Animalcula Infusoria Fluviatilia et Marina. 4to, Havniae et

Leipzig.

1787. COLOMBO, Osservaz. microscop. in giornale della medicina. Venice.

1787. GEORGE ADAMS, Essays on the Microscope. 4to, London.

1788. O. F. MUELLER, Zoologia Danica, seu Animalium Daniae et Norvegiae rariorum

ac minus notorum Descriptiones et Historia. Fol., Havniae.

1791. J. G. BRUGUIERE, Tableau Encyclope"dique et Mdthodique, contenant 1'Helmin-
thologie ou les vers infusoires, les vers intestins et les vers mollusques. 4to,
Paris.

1793. F. VON PAULA SCHRANK, Mikroskopische Wahrnehmungen der Naturforscher.
1799. W. F. GLEICHEN, Dissertation sur la ge"ne*ration des animalcules spermatiques,

ceux d'infusions, avec des observations sur diffe'rentes infusions. 4to, Paris. ,
1803. F. VON P. SCHRANK, Fauna Boica.

1809. LORENZ OKEN, Lehrbuch der Naturphilosophie der lebenden Natur. (Ed. ii., 1831 ;
Ed. iii., 1843.) 8vo, Jena. (Translation by Alfred Tulk, Elements of Physio-
philosophy. 8vo, Ray Society, 1847.)

1812. GRUITHUISEN, Beitrage zur Physiogn. u. Eautognosie.

1814. FOCKE, Ueber Paramaecien : Amtlicher Bericht der Naturforscher- Versamml. in

Bremen.

1815. LORENZ OKEN, Lehrbuch der Naturgeschichte, Bd. iii. Zoologie.
1815. LAMARCK, Histoire des Animaux sans Vertebres. 8vo, Paris.

1817. NlTSCHE, Beitrage zur Infusorienkunde. 'Neue Schriften der naturforschenden

Gesellschaft zu Halle,' Bd. iii. Hft. i.
1817. CUVIER, Regne Animal. 8vo, Paris.
1824. BORY DE ST. VINCENT, Classification des Animaux Microscopiques. ' Encyclopedic

Me*thodique,' torn. ii. 8vo, Paris.

1827. LAMARCK ET BRUGUIERE, Encyclopedic Methodique. vol. i. 4to, Paris.

1828. HEMPRICH AND EHRENBERG, Phytozoa Polygastrica. 'Symbolze Physicae.' Ever-

tebrata I.

1829. C. G. EHRENBERG, Organisation der Infusorien. 'Abhandl. Berl. Akad.,'

1830-2.

1830. G. A. MICHAELIS, Ueber das Leuchten der Ostsee nach eigenen Beobachtungen.

Hamburg.

1830. C. G. EHRENBERG, Beitr. zur Kenntn. der Infusorien und ihrer Geograph. Verbr.,

besonders in Siberien. ' Abhandl. der Berliner Akad.'
j830> ? Organisation, Systematik und Geographische Verhaltniss der Infusions-

thierchen. Fol., Berlin.
J83Q. , Zur Erkenntniss der Organisation in der Richtung des kleinsten Raumes.

410, Berlin.

1831. , Polygastrica. ' Poggendorff s Annalen der Physik.'

1833. C. G. EHRENBERG, Dritter Beitrag zur Erkenntniss grosser Organisation in der
Richtung des kleinsten Raumes. ' Abhandl. Berliner Akad.'

878 CHRONOLOGICAL LIST OF WORKS

1834. C. G. EHRENBERG, Das Leuchten des Meeres. ' Abhandl. Berliner Akad.'

1834. ANDREW PRITCHARD, Natural History of Animalcules, containing descriptions of
all known species of Infusoria. 8vo, London.

1834. PURKINJE, alias PURKYNE, U. VALENTIN, Entdeckung continuerlicher durch

Wimperhaare erzeugter Flimmerbewegungen. ' Miiller's Archiv,' pp. 391-400.

1835. C. V. SIEBOLD, Helminthologische Beitrage. 'Wiegmann's Archiv f. Natur-

geschichte.'

1835. C. G. EHRENBERG, Zusatze zur Erkenntniss grosser organ. Ausbildung in den
kleinsten thierischen Organismen. ' Abhandl. Berliner Akad.'

1835. DONNE, Animalcules microscopiques dans les matieres purulentes, etc., des
organes ge*nitaux de 1'homme et de la femme. 'Ann. des Sc. Nat.,' ser. ii.
torn. vi. p. 157.

1835. F. DUJARDIN, Sur les pr&endus estomacs des Animalcules. 'Ann. des Sc. Nat.,'

ser. ii. torn. iv. p. 314.

1836. LIMOUZIN-LAMOTTE, Note sur les Animalcules conside're's comme cause de

certaines Epidemics. ' Comptes Rendus,' torn. iii. p. 620.

1836. C. G. EHRENBERG, Mittheilungen iiber die in den Feuersteinen bei Delitzsch
mikroskopischen Algen und Infusorien. ' Berichte der Berliner Akad.'

1836. , Die neuesten Fortschritte in der Erkenntniss der Infusorien als Felsmassen.

' Amtl. Bericht iiber die Versamml. deutscher Naturf. u Aerzte in Jena.'

1836. , Ueber das Massenverhaltniss der jetzt lebenden Kieselinfusorien.

' Abhandl. der Berliner Akad.'
1836. , Vorlaufige Mittheilung iiber die Infusorien der Carlsbader Mineralquellen.

' Wiegmann's Archiv,' Bd. ii. p. 240.
1836. GUSTAV W. FOCKE, Ueber einige Organisation sverhaltnisse bei polygastrischen

Infusorien. ' Oken. Isis,' col. 785-7.

1836. SURIRAY, Note sur quelques parasites et produits organiques du Lombric

terrestre. ' Ann. Sci. Nat.' (Zool.) vi.

1837. DONNE, Sur la Trichomonas vaginalis : Recherches microscopiques sur la nature

du mucus. Paris.

1837. C. G. EHRENBERG, Ueber die fossilen Infusorien-Guttungen, Xanthidhtm und
Peridinium, 'Wiegmann's Archiv,' Bd. iii. p. 273.

1837. J. A. LORENT, De Animalculis Infusoriis. 4to, Manhemiis.

1837. BAUPERTHAY ET ROSEVILLE, Sur la presence d'animalcules dans les produits de

diverses se'cre'tions et excretions de 1'homme malade. ' Comptes Rendus,'
torn. v. p. 509.

1838. F. DUJARDIN, Mdmoire sur 1'organisation des Infusoires. 'Ann. des Sc. Nat.,'

ser. ii. torn. x. p. 230.
1838. THEODOR SCHWANN, Ueber die Analogic in der Structur und dem Wachsthume

der Thiere und Pflanzen. Froriep, ' Notizen,' v. col. 33 and 225, and vi.

col. 21.
1838. BAUPERTHAY ET ROSEVILLE, Animalcules microscopiques conside're's comme

cause efficiente du Cancer. ' Comptes Rendus,' torn. vi. p. 64.
1838. , Animalcules microscopiques conside're's comme cause de la putrefaction.

' Comptes Rendus,' torn. vi. p. 357.
1838. MORREN, Sur 1'influence qu'exerce la presence des animalcules de couleur verte,

contenues dans les eaux tranquilles, sur la quantitd et la qualite* des gaz que ces

eaux peuvent dissoudre. ' Comptes Rendus,' torn. vi. p. 276.

RELATING TO THE INFUSORIA. 879

1838. C. G. EHRENBERG, Die Infusionsthierchen als Vollkommene Organismen : ein

Blick in das tiefere Organische Leben der Natur. Fol., Leipzig.

1839. THEODOR SCHWANN, Die Theorie der thierischen Zellenbildung. Froriep,

' Notizen,' Bd. x. col. 225 and 241.

1839. , Mikroskopische Untersuchungen. Berlin.

1839. C. G. EHRENBERG, Ueber nochjetzt zahlreich lebenden Thierarten der Krustebil-

dung. ' Abhandl. Berliner Akad.'
1839. CHARLES CHEVALIER, Des Microscopes et de leur usage. 410, Paris.

1839. C. v. SIEBOLD, Beitrage zur Naturg. der Wirbellosen Thiere. (Opaljnidae.)

1840. F. DUJARDIN, Nouvelle classification des Infusoires base"e sur leur organisation.

' Comptes Rendus,' torn. xi. p. 281.

1840. JOLY, Sur les Animalcules qui colorent en rouge les eaux des marais salants meMiter-
randans. ' Comptes Rendus,' torn. x. p. 200.

1840. C. G. EHRENBERG, Beobachtungen von 274 Infusorien-Arten. 'Monats. der Berl.
Akad.'

1840. , Charakteristik v. neuen Arten von Infusorien. Bericht d. K. Akad. d.

Wiss. Berlin.'

1841. A. AND C. MORREN, Recherches sur la rubeTaction des eaux, et leur oxyge'nation

par les animalcules et les algues. 4to, Bruxelles.
1841. KUTORGA, Naturgeschichte der Infusionsthiere. Carlsruhe.
1841. F. DUJARDIN, Histoire Naturelle des Zoophytes Infusoires. Suites a Buffon. 8vo,

Paris.
1841. WERNECK, Untersuchung iiber mikroskopische Organismen in der Umgegend von

Salzburg. ' Monats. der Berl. Akad.
1841. JOH. MUELLER, Ueber den Bau des Pentacrinus caput- Medusa. 'Abhandl. der

Berl. Akad. (Notice of Peridinidae.)
1841. J. E. PURKYNE, Ueber die neuesten Beobachtungen iiber Infusorien. 'Breslau.

Schles. Gesell. Uebersicht.'
1841. WILHELM WERNECK, Mikroskopische Organismen der Gegend von Salzburg.

' Bericht Berl. Akad., pp. 373-7.
1843. MANDL, Sur la composition du tartre et des enduits muqueux de la bouche.

' Comptes Rendus,' torn. xvii. p. 321.
1843. GRUBY ET DELAFOND, Recherches sur des Animalcules qui se deVeloppent en

grand nombre dans 1'estomac et dans les intestins pendant la digestion des

animaux herbivores et carnivores. 'Comptes Rendus,' torn. xvii. p. 1304.
1843. WERNECK, Die Grundformen der Infusorien in den Heilquellen, nebst allgemeinen

Bemerkungen iiber die Entwickelung derselben von Dr. S. F. Stiebel. ' Wieg-

mann's Archiv,' Bd. ix. p. 105-18.

1843. THEODOR SCHWANN, Vorlaufige Mittheilung betreffend Versuche iiber die

Weingahrung und Faulniss. ' Poggendorfs Annalen,' Bd. xli. p. 184.

1844. AL. DONNE, Cours de Microscopic, compldmentaire des Etudes me'dicales, anatomic

microscopique et physiologic des fluides de 1'^conomie. 8vo, Paris.
1844. F. T. KUETZING, Ueber die Verwandlung der Infusorien in niederen Algenformen.
4to, Nordhausen.

1844. S. GRUBY, Sur une nouvelle espece de Haematozoaire (Trypanosoma). 'Ann. des

Sci. Nat.,' torn. i.

1845. CARL THEODOR VON SIEBOLD AND H. STANNIUS, Lehrbuch der Vergleichenden

Anatomic. Hft. i.

880 CHRONOLOGICAL LIST OF WORKS

1846. C. ECKHARD, Organisationsverhaltnisse der polygastrischen Infusorien. 'Wieg-

mann's Archiv,' Bd. xii. p. 209.
1846. , Entwickelungsstufen der im Innern beobachteten kiigeligen Korper (Stentor

cceruleus). ' Wiegmann's Archiv,' Bd. xii.

1846. G. A. MANTELL, Thoughts on Animalcules: a Glimpse of the Invisible World.

8vo, London.

1847. ED. EICHWALD, Erster Nachtrag zur Infusorienkunde Russlands. ' Bulletin des

Nat. de Moscou,' torn. xx.
1847. SIR J. GRAHAM DALZELL, Rare and Remarkable Animals of Scotland. 4to,

London. (Including many Infusoria.)
1847. L. K. SCHMARDA, Ueber den Einfluss des Lichtes auf die Infusionsthierchen.

Haidinger, 'Bericht Mitth. Freunde Naturw.,' i. pp. 17-21.
1847. , Ueber die Adriatischen Infusorien-Fauna. Haidinger, ' Bericht Mitth.

Freunde Naturw.,' i. pp. 177-80.

1847. , Zur Kenntniss der Adriatischen Infusorien-Fauna. ' Oesterr. Med. Jahrb.,'

pp. i -20.

1848. MAXIMILIEN PERTY, Ueber die Entwickelung einiger Infusorien. ' Bern. Mittheil,'

pp. 193-208.
1848. T. BRIGHTWELL, Sketch of Fauna Infusoria of East Norfolk. 8vo, Norwich.

1848. K. M. DlESlNG, Systematische Uebersicht der Foraminifera monostegia und

Bryozoa anopisthia. ' Sitz. d. K. Akad. d. Wiss. Wien,' Bd. i. Hft. 1-5.

1849. FR. STEIN, Untersuchungen iiber die Entwickelung der Infusorien. 'Wiegmann's

Archiv,' Bd. xv. p. 92.
1849. E. EICHWALD, Zweiter Nachtrag zur Infusorienkunde Russlands. ' Bulletin des

Nat. de Moscou,' torn. xxii.
1849. GERARD BALBIANI, Des organes ge'ne'rateurs des Infusoires dans leurs rapports

avec la fissiparite'. Paris, ' Mem. Soc. Biol.,' i.
1849. C. VON SlEBOLD, Ueber einzellige Pflanzen und Thiere. 'Zeit. Wiss. Zool.,'

Bd. i. 1849. (Translation in ' Quarterly Journal of Microscopical Science,'

1853, pp. in and 195.)

1849. C. WEDL, Beitrage zur Lehre von den Haematozoen. 'Denks. d. math.-nat. Classe

d. K. Akad. d. Wiss. Wien,' Bd. i.

1850. ARTHUR H. HASSALL, A Microscopic Examination of the Water supplied to the

Inhabitants of London and the Suburban Districts. 8vo, London.
1850. S. A. MANTELL, The Invisible World revealed by the Microscope; or, Thoughts

on Animalcules. 8vo, London.
1850. C. W. PEACH, A description of some of the objects which cause the Luminosity of

the Sea.

1850. K. M. DlESlNG, Systema Helminthum. 8vo, Vindobonse.
1850. D'UDEKEM, Mdmoire sur les Metamorphoses des Vorticelliens. ' Ann. des Sc. Nat.'

ser. iv. torn. ix.
1850. JOSEPH LEIDY, Descriptions of three Parasitic Infusoria. 'Trans. Amer. Philos.

Soc.,' vol. ii. ser. 10.
1850. L. SCHMARDA, Neue Formen von Infusorien. 'Denksch. d- K. Akad. der Wiss.

Wien,' Hft. iv. Abth. 2.
1850. C. T. VON SIEBOLD, Ueber Undulirende Membranen. ' Zeit. Wiss. Zool.,'Bd. ii.

Hft. iv.

1850. L. AGASSIZ, Remarks on the little bodies seen on Hydra, which have been described
as parasites. ' Proc. Bost. Soc. Nat. Hist.,' vol. iii. p. 354.

RELATING TO THE INFUSORIA. 88 1

1850. A. DE QUATREFAGES, Observations sur les Noctiluques. 'Ann. des Sc. Nat.,'
2 ser. Zool., xiv. pp. 236-81.

1850. Jos. LEIDY, Nyctotherus, a new genus of Polygastrica allied to Ploesconia. 'Ann.

and Mag. Nat. Hist.,' ser. ii. vol. v. p. 158.

1850-1. , Two new species of Infusorial Entozoa (Nyctotherus ovalis and Bodo

julidis). ' Proc. Acad. Nat. Sci. Philad.,' v. p. 100.

1851. FERDINAND COHN, Beitrage zur Entwickelungsgeschichte der Infusorien. 'Zeit.

Wiss. Zool.,' Bd. iii. pp. 257-79.

1851. MAX. SlGlSMUND SCHULTZE, Beitrage zur Naturgeschichte der Turbellarien
(Parasitic Opalinidae). Greifswalde.

1851. AGNES CATLOW, Drops of Water, their Marvellous and Beautiful Inhabitants

displayed by the Microscope. i8mo, London.

1852. KROHN, Notiz liber die Noctiluca miliaris, Surir. (Mammaria scintillans, Ehr.).

' Wiegmann's Archiv,' Bd. xvii. p. 77.
1852. A. ECKERS, Zur Entwickelungsgeschichte der Infusorien. ' Zeit. Wiss. Zool.,' Bd. iii.

Hft. 4-
1852. MAXIMILIAN PERTY, Zur Kenntniss kleinster Lebensformen. 4to, Bern.

1852. , System der Infusorien. 'Bern. Mittheil.,' pp. 57-67.

1852. ANDREW PRITCHARD, A History of Infusorial Animalcules. 8vo, London.

1852. FR. STEIN, Neue Beitrage zur Kenntniss der Entwickelungsgeschichte der
Infusionsthiere. ' Zeit. Wiss. Zool.,' Bd. iii. Hft. 4.

1852. FERDINAND COHN, Ueber die Entwicklung der Infusorien. 'Breslau. Schles.
Gesell. Uebersicht,' pp. 45-6.

1852. AUGUST KROHN, Notiz uber die Noctiluca miliaris. 'Wiegmann's Archiv f.

Naturgeschichte,' xviii. pp. 77-81.

1853. C. G. EHRENBERG, Ueber neuere Ausschauungen des kleinsten nordlichen Polar-

lebens. ' Monats. der Berl. Akad.'

1853. , Ueber das vorweltliche kleinste Siisswasserleben in ^gypten. ' Bericht.

Akad. Berlin,' pp. 200-3.

1853. FERDINAND COHN, Beitrage zur Entwickelungsgeschichte der Infusorien. 'Zeit.
Wiss. Zool.,' Bd. iv. pp. 253-81.

1853. P. LAURENT, fltudes physiologiques des animalcules des infusions ve'ge'tales

compare's aux organes e'le'mentaires des ve'ge'taux. ' Comptes Rendus,' torn, xxxvi.
p. 1 6.

1854. , fitudes physiologiques sur les animalcules des infusions ve'ge'tales, com-
pare's aux organes e'le'mentaires des ve'ge'taux. 4to, vol. i. Nancy, 1854;
vol. ii. Paris, 1858.

1854. FERDINAND COHN, Beitrage zur Kenntniss der Infusorien. 'Zeit. Wiss. Zool.,'

Bd. v. pp. 420-9.
1854. , Ueber Encystirung von Amphileptus fasciola. 'Zeit. Wiss. Zool.,' Bd. v.

P- 434-
1854. LUDWIG SCHMARDA, Zur Naturgeschichte ^Egyptens. 'Denksch. der Wiener

Akad.,' Bd. vii.

1854. C. G. EHRENBERG, Nova genera et novae species maris profundi. ' Monats. der

Berl. Akad.'
1854. ? Mikrogeologie : Das Erden- u. Felsen-schaflfende Wirken des unsichtbar-

kleinen selbststandigen Lebens auf der Erde. Leipzig.
VOL. II. 2 E

882 CHRONOLOGICAL LIST OF WORKS

1854. W. J. BURNETT, On the Zoological Nature of Infusoria. 'Proc. Boston Soc. Nat.

Hist.,' vol. iv.
1854. ANTON SCHNEIDER, Beitrage zur Naturgeschichte der Infusorien. 'Miiller's

Archiv fiir Anat. u. Phys.'
1854. FR. STEIN, Die Infusionsthiere auf ihre Entwickelungsgeschichte untersucht. 4to,

Leipzig.
1854. PAUL LAURENT, Etudes sur les Animalcules des Infusions. 'Ann. des Sci. Nat.,'

ser. iv. torn. i. p. 38.

1854. LEOPOLD AUERBACH, Ueber Encystirung von Oxytrichapellionella. 'Zeit. Wiss.

Zool.,' Bd. v. p. 430.

1855. KOELLIKER u. SCANZONI, Ueber Trichomonas vaginalis. Scanzoni's ' Beitrage

zur Geburtskunde,' Bd. ii. p. 131.

1855. G. J. ALLMAN, On a Species of Peridinia. ' Quart. Journ. Mic. Sci.,' vol. iii.

1855. , On the Occurrence among the Infusoria of peculiar Organs resembling

Thread-cells. ' Quart. Journ. Mic. Sci.,' vol. iii.

1855. W. BUSCH, Zur Anatomic der Trichodina. ' Miiller's Archiv,' p. 357. (Translated
in ' Quart. Journ. Mic. Sci.,' vol. iii., 1855.)

1855. T. H. HUXLEY, On the Structure of Noctiluca miliaris. 'Quart. Journ. Mic. Sci.,'
vol. iii.

1855. J. W. BAILEY, Note on New Species and Localities of Microscopical Organisms.
' Smithsonian Contrib. to Knowledge,' vol. vii.

1855. Jos. LEIDY, Contributions towards a Knowledge of the Marine Invertebrate Fauna

of Rhode Island and New Jersey. 'Journ. Acad. Nat. Sci. Philadelphia,' vol. iii.

1856. ALEXANDER BRAUN, Ueber Chytridium, eine Gattung einzelliger Schmarotzer-

gewachse auf Algen und Infusorien. 4to, Berlin.
1856. H. J. CARTER, Notes on the Fresh-water Infusoria of the Island of Bombay.

' Ann. Nat. Hist.,' vol. xvii. ser. ii.
1856. PHILIP HENRY GOSSE, Tenby : a Seaside Holiday. Article Zoothamnium.

8vo, London.

1856. Jos. LEIDY, A Synopsis of Entozoa and some of their Ecto-congeners. ' Proc.

Acad. Nat. Sci. Philadelphia,' vol. viii.
1856. N. LIEBERKUHN, Beitrage zur Anatomic der Infusorien. Miiller's 'Archiv,'

Hft. i und 2.

1856. A. SCHULZ, Beitrage zur Kenntniss der Infusorien des Herzogthums Nassau.
' Nassau Jahrbiicher,' Bd. xi.

1856. FR. STEIN, Ueber einige parasitische Infusionsthiere und ihren Bau. ' Abhandl. d.
K. Bb'hmischen Gesell. der Wiss.,' Bd. x., Prag.

1856. J. FR. WEISSE, Zugabe zu A. Schneider's Beitragen zur Naturgeschichte der Infu-
sorien. ' Miiller's Archiv,' Hft. i und 2.

1856. JOHANNES LACHMANN, Ueber die Organisation der Infusorien besonders der

Vorticellen. 'Mull. Archiv,' p. 340-98. (Id., 'Ann. Nat. Hist.,' xix. 1857,
pp. 113-28, 215-41.)

1857. PAGENSTECHER, Trematodenlarven und Trematoden. Heidelberg. (Opalinidae^&c.)
1857. P. H. MALMSTEN, Ueber Paramcecium coli. 'Virchow's Archiv fur Pathol.

Anat. u. Phys.,' Bd. xii. pp. 302-9.

1857. , Infusoires intestinaux chez 1'homme. ' Comptes Rendus,' torn. xlv. p. 934.

1857. T. BRIGHTWELL, On Self-division in Noctiluca. ' Quart. Journ. Mic. Sci.,' vol. v.

\

RELATING TO THE INFUSORIA. 883

1857. H. J. CARTER, On the ultimate Structure of Spongilla, and additional Notes on

Fresh-water Infusoria. ' Ann. Nat. Hist.,' vol. xx. ser. ii.
1857. CLAPAREDE AND LACHMANN, Note sur la reproduction des Infusoires. (Abstract

of Prize Essay communicated to the Academy of France in 1855.) ' Ann. des.

Sci. Nat.,' ser. iv. torn. viii. p. 221.
1857. PHILIP HENRY GOSSE, On the Zoological Position of Dysteria. 'Quart. Journ.

Mic. Sci.,' vol. v.
1857. THOMAS HENRY HUXLEY, On Dysteria, a new Genus of Infusoria. ' Quart.

Journ. Mic. Sci.,' vol. v.

1857. JAMES SAMUELSON, On the Structure of various Infusoria. 'Quart. Journ. Mic.
Sci.,' vol. v.

1857. FR. STEIN, Ueber in der Ostsee bie Wismar beobachteten Infusorienformen.

' Abhandl. d. K. Bohmischen Gesell. der Wiss.,' Bd. x.

1858. G. BALBIANI, Note relative a 1'existence d'une ge'ne'ration sexuelle chez les

Infusoires. 'Comptes Rendus,' xlvi., and 'Ann. Nat. Hist.,' vol. i. ser. iii.
Ib., Recherche sur les organes ge'nerateurs et la reproduction des Infusoires dits

Polygastriques. ' Comptes Rendus,' xlvii.
1858. ED. BORNET, Sur le deVeloppement d'Infusoires dans le Valonia utricularis. ' Me*m.

Soc. Imper. des Sc. Nat. de Cherbourg,' torn. vi.
1858. H. J. CARTER, Note on the Red Colouring Matter of the Sea round the shores of

the Island of Bombay. ' Ann. Nat. Hist.,' vol. i. ser. iii.

1858. , On Eudorina elegans and Cryptoglena. ' Ann. Nat. Hist.,' vol. ii. ser. iii.

1858. G. FRESENIUS, Beitrage zur Kenntniss Mikroskopischer Organismen. 4to,

Frankfort.
1858. MANTEGAZZA, Untersuchungen iiber die Entstehung der Infusorien mit Be-

schreibung einer neuen Art. ' Journ. Instit. Imp. et Roy. Lombard des Sc.,'

nouv. se*r. torn. iii.
1858. SCHENK, Ueber Monadartige Infusorien im Darmkanale der Schmeissfliege.

' Verhandlung des phys.-med. Vereins in Wurzburg,' Bd. viii.
1858. FR. STEIN, Ueber mehrere neue im Pansender Wiederkauer lebende Infusionsthiere;

Ueber die geschlechtliche Fortpflanzung der Infusorien. ' Abhandl. d. K.

Bohmischen Gesell. der Wiss.,' Bd. x.
1858. T. STRETHILL WRIGHT, On Stentor Mulleri and S. castanetts. ' Edinburgh New

Phil. Journ.,' vol. x. p. 97.
1858. J. FR. WEISSE, Ueber die ruhenden Zustande und die Vermehrung der Colpoda

cucullus. ' Mel. Biolog. de 1'Acad. de St. Pe'tersbourg,' torn. iii.
1858. ED. CLAPAREDE ET JOHANNES LACHMANN, Etudes sur les Infusoires et les

Rhizopodes (Extrait des tomes v., vi. et vii. des ' Me*moires de 1'Institut

Genevois,' 1858-1860). Geneve et Bale, 410.
1858. A. DE QUATREFAGES, Rapport sur la question concernant la reproduction des

Infusoires. ' Comptes Rendus,' xlvi. pp. 274-9.
1858. FERDINAND COHN, Ueber Fortpflanzung von Nassula elegans. ' Zeit. Wiss. Zool.,'

Bd. ix. pp. 143-6.
1858. HON. MRS. WARD, A World of Wonders revealed by the Microscope. 8vo,

London.

1858. DAVAINE, Sur la Cercomonas hominis, 'Traitd d'Entoz. Synops.'

1859. LAMBL, Ueber Cercomonas intestinalis. ' Prager Vierteljahrsschrift,' i. p. 51.
1859. FRIEDRICH STEIN, Ueber die ihm bisher bekannt gewordenen und von ihm genauer

erforschten Infusionsthiere, welche im Inneren anderer Thiere eine parasitische
Lcbensweise fuhren. ' Abhandl. Bohm. Gesell.,' Bd. x. pp. 35-8.

2 E 2

884 CHRONOLOGICAL LIST OF WORKS

1859. F. STEIN, Ueber die wahrend der verflossenen Sommerferien in der Ostsee bei
Wismar von ihm beobachteten Infusorien. 'Abhandl. Bohm. Gesell.,' Bd. x.
pp. 62-3.

1859. , Characteristik neuer Infusoriengattungen. ' Prager Lotos,' Januar und

Marz, Jahrg. ix.

1859. , Einige seiner neuesten Entdeckungen in der Infusorienkunde. ' Sitz-

ungsberichte d. K. Bohmischen Gesell. der Wiss; in Prag.'

1859. , Der Organismus der Infusionsthiere. Abth. I. HYPOTRICHA. Fol.,

Leipzig.
1859. J. REAY GREENE, A Manual of the Protozoa. 8vo, London.

1859. H. J. CARTER, On Eudorina, Spongilla, Astasia, Euglena, and Cryptoglena ; On
Plcesconia and Kerona. ' Ann. Nat. Hist.,' vol. iii. ser. iii.

1859. T. W. ENGELMANN, Ueber Fortpflanzung von Epistylis crassicollis, Carckesium
polypinum, und liber Cysten auf den Stocken des letzteren Thieres. 'Zeit.
Wiss. Zool.,' Bd. x. Hft. 2. pp. 503-6.

1859. P. H. GOSSE, Evenings at the Microscope, or researches among the minuter organs
and forms of Animal Life. 8vo, London.

1859. A. H. HASSAL, On the development and signification of Vibrio lineola, Bodo

urinarius, and certain fungoid and other organic productions developed in

alkaline and albuminous urine. ' Lancet,' November.
1859. W. KUEHNE, Untersuchungen liber Bewegungen und Veranderungen der Con-

tractilen Substanzen. ' Miiller's Arch. f. Anat. u. Phys.,' pp. 514-641, 748-835.
1859. F. LEYDIG, Ueber Parasiten niederer Thiere. 'Virchow's Archiv f. Path. Anat.,'

Bd. xiii. pp. 280-2.

1859. J. LACHMANN, Ueber einige neue entdeckte Infusorien, und liber Contractileblasen
bei den Infusorien. ' Rheinl. u. Westphal. Sitzungsber.,' xvi. pp. 66-8, 91-2.

1859. T. STRETHILL WRIGHT, On new Protozoa, Lagotia producta, Zooteira relegata,
Corethra sertitlaria. ' Proc. Phys. Soc. Edinb.,' ii. p. 26.

1859. C. G. EHRENBERG, Ueber das Leuchten und neue Mikroskopische Leuchtthiere

des Mittelmeeres. ' Monats. der Berl. Akad.'

1860. S. BALBIANI, Observations et experiences sur les phdnomenes de reproduction

fissipare chez les Infusoires Cilie's. ' Comptes Rendus,' 1., Paris.
1860. , Note sur un cas de parasitisme improprement pris pour une mode de

reproduction des Infusoires Cilie's. ' Comptes Rendus,' li., Paris.
1860. , Etudes sur la reproduction des Protozoaires, du role desorganes ge'ne'rateurs

dans la division spontane'e des Infusoires Cilie's. Brown-Sequard, 'Journ.

Physiol.,' torn. iii.
1860. ED. CLAPAREDE, Recherches sur les Annelides &c. observes dans les Hebrides.

' Mem. Soc. Phys. Geneva,' torn. xvi. (Notice of Parasitic Opalinida?.)

1860. KEFERSTEIN, Ueber Opalinen im Darme der Nemertinen. ' Zeit. Wiss. Zool.,' Bd. xii.

1860. LEYDIG, Naturgeschichte der Daphniden. 4to, Tubingen, S. 33, Anm. (Note on
contractile fibre of Zoothamniuiri).

1860. FR. STEIN, Ueber Leucophrys patula und liber zwei neue Infusorien-Gattungen

Gyrocoris und Lophomonas ; Ueber die Eintheilung der Holotrichen Infu-
sionsthiere nebst einigen neuen Gattungen und Arten. ' Sitz. d. K. Bohmischen
Gesell. der Wiss.'

1 86 1. RUD. LEUCKART, Bericht liber die Leistungen in der Naturgesch. der niederen

Thiere wahrend d. J. 1859. 'Archiv f. Naturgesch.,' Bd. ii.

RELATING TO THE INFUSORIA. 885

1861. S. BALBIANI, Recherches sur les phdnomenes sexuels des Infusoires. Brown-

Sequard, ' Journ. Physiol.,' torn. iv.
1861. H. J. CARTER, Notes and Corrections on the Organization of Infusoria. 'Ann.

Nat. Hist.,' vol. viii. ser. iii.
1861. J. EBERTH, Ueber ein neues Infusorium im Darm verschiedener Vogel. 'Zeit.

Wiss. Zool.,' Bd. ii. Hft. i.

1 86 1. C. J. EHRENBERG, Ueber Drepanidium pectinatum. ' Bonplandia,' p. 317. 4to,

Hannover.

1861. T. W. ENGELMANN, Ueber Noctiluca. 'Zeit. Wiss. Zool.,' Bd. xii.
1861. R. LEUCKART, Ueber Paramecium colt. ' Wiegmann's Archiv,' Bd. xxvii.
1861. ANDREW PRITCHARD, A History of Infusoria, including the Desmidiaceae and

Diatomaceae. Ed. 4, 8vo, London.
1861. ROUGET, Ueber das Verhalten des Stielmuskels der Vorticellen in polarisirtem

Lichte. ' Journ. de Phys.,' torn. v. p. 247.
1861. H. J. SLACK, Marvels of Pond Life. 8vo, London.
1861. FR. STEIN, Ueber im Darmcanal der Regenwiirmer aufgefundenes neues

Infusionsthierchen ; Ueber ein neues parasitisches Infusionsthier aus dem

Darmcanal von Paludinen ; Ueber der Conjugation der Infusionsthiere und

iiber die geschlechtliche Fortpflanzung der Stentoren. ' Sitz. d. K. Bohmischen

Gesell. der Wiss.,' pp. 42, 62, 85.
1861. J. FR. WEISSE, Vegetabilische Quellen von Infusorien. 'Met. Biol. Bull. Acad.

Imp. Petersburg,' torn. iv.
1861. A. O. WRZESNIOWSKI, Observations sur quelques Infusoires. 'Ann. des Sci.

Nat.,' ser. iv. torn. xvi. p. 327.

1 86 1. L. SCHMARDA, Reise um die Erde. Braunschweig.

1862. F. STEIN, Ueber Paramczcium (?) coli Malmsteen. 'Amtl. Bericht Deutscher

Naturforschervers. Karlsbad,' p. 165.
1862. L. CIENKOWSKI, Zur Entwickelungsgeschichte der Myxomyceten. ' Pringsheim's

Jahrbiicher,' Bd. iii. Hft. 2 and 3.
1862. ERNST EBERHARD, Abhandlung iiber die Infusorienwelt. ' Oster Programm der

Realschule zu Coburg.'
1862. T. W. ENGELMANN, Zur Naturgeschichte der Infusionsthiere. 'Zeit. Wiss. Zool.,'

Bd. xi. Hft. 4, pp. 347-93-
1862. FR. STEIN, Kritische Besprechung der Infusorien Abhandlungen von E. Eberhard

und A. Wrzesniowski. ' Sitz. d. K. Bohmischen Gesell. der Wiss.'
1862. , Neue Infusorienformen in der Ostsee. 'Bericht. Deutsch. Naturf.

Versamml.,' Bd. xxxvii. pp. 161-2.
1862. STEINBERG, Ueber die auf und zwischen den Menschlichen Zahnen sich ansam-

melnde weisse Substanz. 'Zeit. f. neuer Medicin,' Kiew.
1862. J. FR. WEISSE, Vegetabilische Quellen von Infusorien. 'Bull. Soc. Imp. St.

Petersburg,' Bd. iv.

1862. STRETHILL WRIGHT, Observations on British Zoophytes, Zooteira relegata,

Freya (Lagotia) obstetrica, &c. ' Edinburgh New Philosophical Journal,'
vol. xvi.

1863. FERDINAND COHN, Verhalten der griinen mikroskopischen Pflanzen und Thiere

zum Lichte. ' Breslau. Schles. Gesell. Jahrb.,' pp. 102-5.

1863. J. FR. WEISSE, Verzeichniss aller von mir in einem 3O-jahrigen Zeitraume zu St.
Petersburg beobachteten Infusorien. ' Bull, dc la Soc. Imp. d. Natur. de
Moscou.'

886 CHRONOLOGICAL LIST OF WORKS

1863. H. J. CARTER, Note on the Colouring Matter of the Red Sea. 'Ann. Nat. Hist.,'

vol. xi. ser. iii.
1863. Du PLESSIS, De 1'action des substances me*dicamenteuses sur les Infusoires.

8vo, Lausanne.
1863. C. G. EHRENBERG, Ueber die seit 27 Jahren noch wohl erhaltenen Organisations-

Praparate des mikroskopischen Lebens. ' Abhandl. Akad. (aus dem Jahre

1862) Berlin.'
1863. R. LEUCKART, Die Menschlichen Parasiten, und die von ihnen herriihrenden

Krankheiten. Bd. i. 8vo, Leipzig und Heidelberg.
1863. E. MECZNIKOW, Untersuchungen iiber den Stiel der Vorticellen. ' Muller's Archiv

fiir Anat. und Physiol.' (Translation 'Journ. Mic. Sci.,' 1863.)
1863. FR. STEIN, Ueber die Hauptergebnisse der neuen Infusoriensforschungen. 'Wien.

Almanach, ' pp. 153-79.
1863. L. PASTEUR, Nouvel example de fermentation determined par des animalcules

infusoires pouvant vivre sans gaz oxygene libre et en dehors de tout contact

avec I'air de 1'atmosphere. ' Comptes Rendus,' torn. Ivi.

1863. T. W. ENGELMANN, Ueber die Vielzelligkeit von Noctiluca. 'Zeit. Wiss. Zool.,'
Bd. xii. pp. 564-6.

1863. MAXIMILIEN PERTY, Ueber die Identitat einiger Algen- und Infusoriensippen.

' Bern. Mittheil.,' pp. 90-8.

1864. COSTE, DeVeloppement des Infusoires cilie"s dans une maceration de foin. ' Comptes

Rendus,' torn. lix. p. 149.

1864. , DeVeloppement des Infusoires cilie*s dans une maceration de foin. 'Ann.

des Sc. Nat.,' ser. v. torn. ii. p. 240.

1864. G. J. ALLMAN, On the occurrence of Amcebiform Protoplasm and the emission
-• of Pseudopodia among the Hydroida. ' Quart. Journ. Mic. Sci.,' vol. v.,

1864.
1864. H. J. CARTER, On Freshwater Rhizopoda of England and India. 'Ann. Nat.

Hist.,' vol xiii., ser. iii.
1864. A. DE BARY, Die Mycetozoen : ein Beitrag zur Kenntniss der niedersten

Organismen. 8vo, Leipzig.

1864. DESGOUTTES, Observations de la mode de fe"condation dans VAmphileptusfasciola.

' Comptes Rendus,' torn. lix.
1864. M. J. D'UDEKEM, Description des Infusoires de la Belgique. ' Mem. de 1'Acad.

Roy. de Belgique,' torn, xxxiv.

1864. GRIFFITH, On the Contractile Vesicle of Infusoria. 'Quart. Journ. Mic. Sci.'

1864. A. KOELLIKER, Icones Histologicae ; oder Atlas der Vergleichenden Gewebelehre.

4to, Leipzig.
1864. M. J. LEMAIRE, Origine des Microphytes et des Microzoaires qui existent dans

I'air. ' Comptes Rendus,' torn. lix.

1864. , Recherches sur les Microphytes et sur les Microzoaires. ' Comptes

Rendus,' lix.

1864. LINDEMANN (Chilodon cucullus and Euplotes ckarori). 'Bull. Soc. Imp. de
Moscou.'

1864. ELI AS MECZNIKOW, Ueber die Gattung Spharophrya. ' Muller's Archiv f. Anat.
u. Phys.,' p. 258.

1864. V. MEUNIER, Sur la resistance vitale des Colpodes encyste'es. 'Comptes
Rendus,' torn. lix.

RELATING TO THE INFUSORIA. 887

1864-5. A. P. NINNI, Sulla mortalita dei gamberi (Astacus fluviatilis) nel Veneto e piu
particolarmente nella provincia trevigiana. 'Atti dell' Imp. Roy. Istituto
Veneto,' torn. x. ser. iii.

1864. MAXIMILIEN PERTY, Ueber Algen und niedere Seethiere der Elbemiindung.

' Berner Mittheilungen,' No. 539, pp. 89-100.
1864. , Bemerkungen iiber Infusorien. ' Schweiz. Naturf. Gesellsch. zu Zurich,'

xlviii. pp. 527-36.

1864. F. A. POUCHET, Embryoge'nie des Infusoires die's. ' Comptes Rendus,' torn. lix.

1864. FR. STEIN, Ueber den Proteus tenax Muller und iiber die Infusoriengattungen

Distigma Ehr. und Epiclintes Stein. ' Sitz. d. K. Bohmischen Gesell. der Wiss.'

1865. H. J. CARTER, On the Fresh and Salt Water Rhizopoda of England and India ;

Remarks on Prof. H. J. Clark's Peridiniunt cypripedium. 'Ann. Nat. Hist.,'
vols. xv. and xvi. ser. iii.

1865. L. CIENKOWSKI, Beitrage zur Kenntniss der Monaden. 'Archivf.Mik.Anat.,'

Bd. i. Hft. 2 and 3.
1865. H. JAMES-CLARK, Proof of the Animal Nature of the Cilio-flagellate Infusoria.

' Proc. Amer. Acad.,' vol. vi.
1865. G. FRESENIUS, Die Infusorien des Seewasseraquariums. 'Der Zoologische Garten,'

No. 3 and 4, Frankfort.
1865? A. QUENNERSTEDT, Bidrag til Sveriges Infusorie-fauna. Hft. i. 'Acta Univer-

sitatis Lundensis,' 1865.
1865. J. SAMUELSON, On the Development of certain Infusoria. 'Proc. Roy. Soc.,'

vol. xiv.

1865. COSTE, DeVeloppement des Infusoires cili^s dans une maceration de foin. 'Ann.

des Sci. Nat.,' ser. v. torn. ii. p. 240.

1865-6. K. M. DIESING, Revision der Prothelminthen. 'Sitz. d. K. Akad. d. Wiss.
Wien,' Bd. Iii. and liii.

1866. W. ARCHER and J. BARKER, On Anthophysa Muelleri. ' Quart. Journ. Mic. Sci.,'

vol. vi., N. S.
1866. H. JAMES-CLARK, On the Structure and Habits of Anthophysa Muelleri Bory.

' Amer. Journ. Sci. and Arts,' vol. xlii. pp. 223-30.
1866. , On the Affinities of Peridinium cypripedium and Urocentrum turbo.

' Ann. Nat. Hist.,' vol. xviii. ser. iii.
1866. , On the Vestibular Bristle or Lash of one of the Vorticellidae. ' Proc. Bost.

Soc. Nat. Hist.,' vol. x. pp. 231-2.
1866. FERDINAND CORN, Neue Infusorien im Seeaquarium. ' Zeit. Wiss. Zool.,'

Bd. xvi. Hft. iii.
1866. FAMINITZIN, Action de la lumiere sur les mouvements du Chamydomonas and

Euglena. ' Bull. Acad. Imp. St. Pe'tersbourg,' vol. x.
1866. PASTEUR, De la ge'ne'ration spontane'e des moisissures ve'getales et des animalcules

infusoires. ' Comptes Rendus,' torn. Ixiii.
1866. SCHWALBE, Ueber die Contractilen Behalter der Infusorien. ' Archiv f. Mik.

Anat.,' Bd. ii.

1866. W. ZENKER, Beitrage zur Naturgeschichte der Infusorien. 'Archiv f. Mik.

Anat.,' Bd. ii.

1867. ED. CLAPARJIDE, Sur les Licnophora, nouveau genre de la famille Urceolarina.

' Ann. des Sci. Nat.,' torn. viii. ser. iv.

1867. A. QUENNERSTEDT, Bidrag til Sveriges Infusorie-fauna. Hft. ii. ' Acta Universitatis
Lundensis,' 1867.

888 CHRONOLOGICAL LIST OF WORKS

1867. C. ROUGET, Note sur les phe'nomenes de contraction musculaire chez les
Vorticelles. ' Comptes Rendus.'

1867. OSCAR SCHMIDT, Eine Reclamation, die geformte Sarcode der Infusorien
betreffend. ' Archiv f. Mik. Anat.,' Bd. iii.

1867. POULET, Sur la presence d'Infusoires dans 1'air expire* pendant le cours de la

coqueluche. ' Comptes Rendus,' torn. Ixv. p. 254,

1868. FR. STEIN, Der Organismus der Infusionsthiere. Abth. II. HETEROTRICHA.

Leipzig, fol.

1868. J. V. CARSU, Ueber Noctiluca miliaris. 'Archiv f. Mik. Anat.,' Bd. iv.
1868. ERNST HAECKEL, Natiirliche Schopfungsgeschichte. Berlin.

1868. R. GREEF, Beobachtungen iiber die Fortpflanzung von Infusorien. ' Bonn. Sitz.
Ber. Unterrhein. Gesell.,' pp. 90-2.

1868. H. JAMES-CLARK, On the Spongiae Ciliatae as Infusoria Flagellata. ' Mem. Bost.

Soc. Nat. Hist.,' vol. i. part 3.
1868. W. DONITZ, Ueber Noctiluca miliaris. ' Reichen u. Du Bois Raymond's Archiv.'

1868. , Ueber Noctilucen. 'Archiv f. Mik. Anat.'

1868. ERNST EBERHARD, Der Organismus der Infusionsthiere. 'Zeit. Wiss. Zool.,'

Bd. xviii.
1868. , Ueber die Fortpflanzung von Bursaria truncatella. 'Zeit. Wiss. Zool.,

Bd. xviii. (Translation ' Quart. Journ. Mic. Sci.,' 1868.)

1868. MARCHAND, De la Reproduction des Infusoires. Etude Mddico-Zoologique. Paris.
1868. E. MECZNIKOFF, Ueber Noctiluca. ' Verhandl. der Petersburg. Naturf. Zool.'
1868. GUSTAV SCHOCK, Die Mikroskopischen Thiere des Siisswasser- Aquariums. 8vo,

Leipzig.

1868. J. G. TATEM, On a New Species of Microscopic Animals. 'Trans. Roy. Mic. Soc.,'

vol. xvi. new ser.

1869. C. J. MUELLER, On Vaginicola valvata. l Quart. Journ. Mic. Sci.,' vol. ix.

1869. H. J. CARTER, Notes on the Filigerous Green Infusoria of the Island of Bombay.

' Ann. Nat. Hist.,' vol. iii. ser. iii.
1869. N. MOXON, Anatomy of Stentor and on its Mode of Division. ' Journ. of Anat. and

Physiol.,' vol. iii. pt. 2.
1869. A. QUENNERSTEDT, Bidrag til Sveriges Infusorie-fauna. Hft. iii. 'ActaUniver-

sitatis Lundensis,' 1869.
1869. W. SAVILLE KENT, On some New Infusoria from the Victoria Dock. 'Month.

Mic. Journ.,' vol. i.
1869. SCHAFFHAUSEN, Eine Darstellung von der Organisation der Infusorien. 'Sitz.

der Nied. Gesellsch. zu Bonn.'
1869. J. G. TATEM, On a New Infusorium. ' Month. Mic. Journ.,' vol. i. p. 117.

1869. A. WRZESNIOWSKI, Ein Beitrag zur Anatomic der Infusorien. 'Archiv f. Mik.

Anat.,' Bd. v. Hft. I.

1870. L. ClENKOWSKl, Ueber Palmellaceen und einige Flagellaten. 'Archiv f. Mik.

Anat.,' Bd. vi. Hft. 4.
1870. CARL GEGENBAUR, Grundzuge der Vergleichenden Anatomic. Ed. 2. Leipzig,

roy. 8vo.
1870. E. H. GIGLIOLI, La Fosforescenza del Mare, colla descrizione di due nuove

Noctiluce. ' Atti Ace. Tor.'
1870-1. R. GREEF, Untersuchungen iiber den Bau und die Naturgeschichte der Vorti-

cellen. ' Wiegmann's Archiv,' Bd. xxxvi. and xxxvii.

RELATING TO THE INFUSORIA. 889

1870. E. RAY LANKESTER, Remarks on Opalina and its Contractile Vesicles. 'Quart.

Journ. Mic. Sci.,' vol. x. new ser.
1870. W. C. M'lNTOSH, On the Structure of Tubifex (Parasitic Opalina}. * Trans. Roy.

Soc. Edinburgh/ vol. xxvi.

1870. J. G. TATEM, A Contribution to the Teratology of Infusoria. 'Month. Mic. Journ.,'

vol. iii.

1870. , Notes on New Infusoria. 'Month. Mic. Journ.,' vol. iv. No. 4.

1870. A. WRZESNIOWSKI, Beobachtungen iiber Infusorien aus der Umgebung von

Warschau. ' Zeit. Wiss. Zool.,' Bd. xx. Hft. 4.
1870. R. GREEF, Ueber den Bau und die Fortpflanzung der Vorticellen. ' Hallier's Zeit-

schrift f. Parasitenkunde,' Bd. iii. pp. 96-100.

1870. ERNST HAECKEL, Die Catallacten, eine neue Protistengruppe. 'Jenaische
Zeitschrift,' Bd. vi.

1870. C. A. BARRETT, A new tube-dwelling Stentor (S. Barrett). 'Monthly Micro-

scopical Journal,' vol. iii.

1871. H. J. CARTER, Confirmation of Prof. James-Clark's drawing of the " Collar" round

the cilium of the sponge-cell. 'Ann. Nat. Hist.,' ser. iv. vol. viii. p. 9.
1871. , Note on a Freshwater Species of Ceratium from the Lake of Nynee Tal in

Kumaon. 'Ann. Nat. Hist.,' vol. viii. ser. iv.
1871. H. JAMES-CLARK, Note on the Infusoria Flagellata and the Spongiae ciliatae.

' Amer. Journ. Sci.,' vol. i. pp. 113-14.

1871. W. ALENITZIN, Neue Infusorien. 'Protocolle der Gese'llschaft der Naturf. zu

Kasan.'

1871. W. ARCHER, On Aporea ambigua Bailey. ' Quart. Journ. Mic. Sci.,' vol. xi.
1871. W. ARCHER and J. BARKER, Remarks on Phacus and Euglena. ' Quart. Journ.

Mic. Sci.,' vol. xi.
1871. L. CIENKOWSKI, Ueber Schwarmerbildung bei Noctilnca miliaris. 'Arch. f.

Mik. Anat.,' Bd. vii. Hft. 2.
1871. , Ueber Schwarmerbildung bei Radiolarien. ' Archiv f. Mik. Anat.,' Bd. vii.

Hft. 4. (Translation ' Quart. Journ. Mic. Sci.,' vol. x., 1876.)
1871. E. RAY LANKESTER, On Undulina, the Type of a New Group of Infusoria. ' Quart.

Journ. Mic. Sci.,' vol. xi. new ser.
1871. W. SAVILLE KENT, Notes on Prof. James-Clark's Flagellate Infusoria, with

Description of New Species. ' Month. Mic. Journ.,' vol. vii. No. 36.
1871. L. SCHMARDA, 'Zoologie,' Bd. i. and ii. 8vo, Wien.

1871. WlLLEMOES-SUHM, Biologische Beobachtungen uber niederen Meeresthiere.

' Zeit. Wiss. Zool.,' Bd. xxii. Hft. 3.

1872. G. J. ALLMAN, Notes on Noctihica. ' Quart. Journ. Mic. Sci.,' vol. xii. new. ser.
1872. , On some points in the development of Vorticellidas. 'Quart. Journ.

Mic. Sci.,' vol. xii. new ser.
1872. W. ARCHER, On a form of Chlamydomonad. 'Journ. Mic. Soc.,' vol. xii.

1872. H. C. BASTIAN, On some Heterogenetic modes of origin of Flagellated Monads,
Fungus Germs, and Ciliate Infusoria. ' Proc. Roy. Soc.,' vol. xx.

1872. OSCAR VON GRIMM, Ueber Synura u-vella und Uroglena volvox und den wahr-
scheinlichen genetischen Zusammenhang der Catallacten mit den Schwammen.
' Nachrichten von der Gottinger Gesellsch. der Wiss.'

1872. F. STEIN, Eine in Rotifera vorkommende neue Monadenformen (Trypanococcus).
' Leipziger Naturforschendersammlung.'

890 CHRONOLOGICAL LIST OF WORKS

1872. ROSSBACH, Ueber die rhythmischen Bewegungserscheinungen der einfachsten
Organismen. ' Verh. der Wiirzburger physik.-med. Gesellsch.,' Bd. ii.

1872. J. G. TATEM, On a presumed phase of Actinophryan life. 'Month. Mic. Journ.,'

vol. vii. p. 169.

1873. R. GREEF, Protozoen-fauna der Moos und Flechtenkrusten. 'Marburger Sitzungs-

bericht,' p. 23.
1873. C. G. EHRENBERG, Die das Funkeln und Autblitzen des Mittelmeeres bewirkenden

unsichtbar kleinen Lebensformen. ' Festschr. Nat. Fr.'
1873. E. G. BALBIANI, Observations sur le Didinium nasutum Stein. ' Archives Zool.

Expe"rimentale,' torn. ii.

1873. O. BUETSCHLI, Einiges iiber Infusorien. 'Arch. f. Mik. Anat.,' Bd. ix.
1873. L. CIENKOWSKI, Ueber Noctiluca miliaris. 'Arch. f. Mik. Anat.,' Bd. ix. Hft. i.

1873. W. H. DALLINGER and J. DRYSDALE, Researches on the Life-history of a Cerco-
monad : a Lesson in Biogenesis. ' Month. Mic. Journ.,' vol. x. No. 56.

1873. > Further Researches into the Life-history of the Monads. ' Month. Mic.

Journ.,' vol. x. No. 60.
1873. EDUARD EVERTS, Untersuchungen an Vorticella nebulifera. 'Zeit. Wiss. Zool.,'

Bd. xxiii. Hft. 4.
1873. ERNST HAECKEL, Zur Morphologie der Infusorien. 'Jenaische Zeitschrift,'

Bd. vii. Hft. 4.
1873. , Ueber einige neue pelagische Infusorien. 'Jenaische Zeitschrift,' Bd. vii.

Hft. 4.
1873. TH. HINCKS, On the Protozoon Ophryodendron abietinum Cl. & Lach. 'Quart.

Journ. Mic. Sci.,' vol. viii. No. 49.
1873. E. RAY LANKESTER, Blue Stentorin : the colouring matter of Stentor cceruleus.

' Quart. Journ. Mic. Sci.,' vol. xiii. No. 50.

1873. J- H. SALISBURY, On Infusorial Catarrh and Asthma : the cause of Hay-fever,

&c. ' Hallier's Zeitschrift fur Parasitenkunde,' Bd. iv. Hft. i.

1874. W. ALENITZIN, Wagnerella cylindroconica—zvn. neues Infusionsthier. 'Arch. f.

Mik. Anat.,' Bd. x. p. 122.
1874. CLAUS, Bemerkungen zur Lehre von der Einzelligkeit der Infusorien. 'Verhandl.

der k.-k. zoolog. bot. Gesellsch. in Wien.'
1874. W. H. DALLINGER and J. DRYSDALE, Further Researches into the Life-history

of the Monads. 'Month. Mic. Journ.,' vols. xi. and xiL, Nos. 61, 62, 63,

and 72.
1874. E. RAY LANKESTER, On Torquatella typica, a new type of Infusoria allied to the

Ciliata. ' Quart. Journ. Mic. Sci.,' vol. xiv. new ser.

1874. Jos. LEIDY, Notice of some Fresh-water Infusoria (Cothurnia and Dendrosoma).

' Proc. Acad. Nat. Hist. Philadelph.,' p. 140.

1875. EUG. WARMING, Om noget ved Danmarks Kyster levende Bacterier. ' Vidensk.

Medd. fra Naturhist. Foren i Kjobenhavn.'

1875. G. J. ALLMAN, Progress recently made in our knowledge of the Ciliate Infusoria :
President's Anniversary Address to the Linnean Society, May 24th, 1875.

1875. BALBIANI, Sur la ge'ne'ration sexuelle des Vorticelliens. 'Comptes Rendus,'

torn. Ixxxi. p. 676.

1875. E. BUCKE, Die Acinete im Aquarium. 'Zool. Gart.,' Frankfort, Bd. xvi.
1875. W. H. DALLINGER and J. DRYSDALE, Further Researches into the Life-history

of the Monads. ' Month. Mic. Journ.,' vol. xiii. No. 77.

RELATING TO THE INFUSORIA. 891

1875. RICHARD HERTWIG, Ueber Podophrya gemmipara, nebst Bemerkungen zum Bau,

u.s.w. ' Morphologisches Jahrbuch,' Bd. i. Hft. i.
1875. C. T. HUDSON, On Cephalosiphon and a new Infusorian. 'Month. Mic.

Journ.,' vol. xiv. No. 82.
1875. T. H. HUXLEY, On the Classification of the Animal Kingdom. 'Journ. Lin. Soc.,

Zoology,' vol. xii. No. 59.
1875. W. H. JACKSON, On a new Peritrichous Infusorian (Cyclochceta spongillce). 'Quart.

Journ. Mic. Sci.,' vol. xv. new ser. No. 69.

1875. W. LAMBL, Ueber Parasitischen Infusorien. ' Petersburger Medicin. Zeitung,'

No. 33.

1876. O. BUETSCHLI, Studien iiber die ersten Entwickelungsvorgange der Eizelle, die

Zelltheilung, und die Conjugation der Infusorien. ' Abhandl. d. Senckenber-
gischen Naturf. Gesellsch. Frankfort,' Bd. x.

1876. W. H. DALLINGER, Experiments with a sterile putrescible fluid exposed alter-
nately to an optically pure atmosphere and to one charged with known organic
germs of extreme minuteness. ' Month. Mic. Journ.,' vol. xvi. No. 96.

1876. T. W. ENGELMANN, Ueber Entwickelung und Fortpflanzung von Infusorien.
' Morphologisches Jahrbuch,' Bd. i. Hft. 4.

1876. FOUQUET, Note sur une espece d'Infusoires parasites des poissons d'eau douce.
' Archives de Zoologie Expe'rimentale,' torn. v.

1876. E. DE FROMENTEL, Etudes sur les Microzoaires ou Infusoires proprement dits.
4to, Paris.

1876. R. HERTWIG, Beitrage zu einer einheitlichen Auffassung der verschiedenen Kern-
formen. ' Morphologisches Jahrbuch,' Bd. ii. Hft. I.

1876. G. v. KOCH, Zwei Acineten auf Plumularia setacea. Jena.

1876. MAUPAS, Sur 1'organisation et le passage a I'e'tat mobile de la Podophrya fixa.

' Archives de Zoologie Expe'rimentale,' torn. v.
1876. H. SIMROTH, Zur Kenntniss des Bewegungsapparates der Infusionsthiere. ' Archiv

f. Mik. Anat.,' Bd. xii.
1876. JOHN TYNDALL, The optical deportment of the Atmosphere in relation to the

phenomena of putrefaction and infection. ' Phil. Trans.,' vol. clxvi., part i.
1876. G. E. WALLICH, Deep-sea Researches on the Biology of Globigerina. 8vo,

London.

1876. R. LEUCKART, Die Menschlichen Parasiten, Bd. ii. (Issued in parts from 1867 to

1876).

1877. R. HERTWIG, Ueber den Bau u. die Entwicklung der Spirochona gemmipara.

' Jenaische Zeitschrift,' Bd. xi. pp. 150-84.

1877. JULIEN DEBY, Note sur un Infusoire nouveau pour la Faune Belgique. ' Bull. Soc.
Beige de Microscopic.'

1877. ERNST HAECKEL, Die Physemarien (Haliphysema u. Gastrophysema\ Gastrasaden
der Gegenwart. ' Jenaische Zeitschrift,' Bd. xi. pp. 1-54.

1877. O. A. GRIMM, Zur Lehre von den einfachsten Thieren (St. Petersburg). Abstract
in ' Jahrbericht Anat. Phys.,' vii. Hft. ii. p. 8.

1877. G. J. ALLMAN, Recent Researches among some of the more simple Sarcode

Organisms : President's Anniversary Address to the Linnean Society, May 24th,

1877-
1877. O. BUETSCHLI, Ueber den Dendrocometes paradoxus, nebst einigen Bemerkungen

iiber Spirochona. gemmipara und die contractilen Vacuolen der Vorticellen.

' Zeit. Wiss. Zool.,' Bd. xxviii. Hft. i and 2.

892 CHRONOLOGICAL LIST OF WORKS

1877. B. EYFERTH, Die Mikroskopischen Siisswasserbewohner. 8vo, Brunswick.

1877. R. HERTWIG, Ueber Leptodiscus medusoides, eine neue den Noctilucen verwandte

Flagellate. ' Jenaische Zeitschrift,' Bd. xi. Hft. 3.

1877. T. H. HUXLEY, The Anatomy of Invertebrated Animals. 8vo, London.
1877. JOHN TYNDALL, Further Researches in the deportment and vital persistence of

putrefactive and infective organisms from a physical point of view. ' Phil.

Trans.,' vol. clxvii., part i.
1877. A. WRZESNIOWSKI, Beitrage zur Naturgeschichte der Infusorien. 'Zeit. Wiss.

Zool.,' Bd. xxix. Hft. 3.

1877. ERNST ZELLER, Untersuchungen liber die Fortpflanzung und die Entwicklung der

Opalinen. ' Zeit. Wiss. Zool.,' Bd. xxix. Hft. 3.

1878. O. BUETSCHLI, Beitrage zur Kenntniss der Flagellaten und einiger verwandten

Organismen. ' Zeit. Wiss. Zool.,' Bd. xxx. Hft. 2. (Translation ' Quart. Journ.

Mic. Sci.,' vol. xix. No. 73.)
1878. W. H. DALLINGER, On the Life-history of a minute Septic Organism. 'Proc.

Roy. Soc.,'vol. xxvii. No. 187.
1878. T. R. LEWIS, Flagellated Organisms in the Blood of healthy Rats. 'Quart.

Journ. Mic. Sci.,' vol. xxix. No. 73.
1878. C. VON MERESCHKOWSKY, Studien iiber Protozoen des nordlichen Russland.

' Archiv f. Mik. Anat.,' Bd. xvi. Hft. 2.
1878. W. SAVILLE KENT, Observations upon Professor Ernst Haeckel's group of the

Physemaria, and on the affinity of the Sponges. 'Ann. and Mag. Nat. Hist.,'

ser. v. vol. i. No. i.

1878. , On a New Field for the Microscopist. ' Popular Science Review,' new

ser. vol. ii. pp. 113-32.
1878. EDWIN SMITH, Fresh-water Life— Infusoria. 'Midland Naturalist, vol. i. Nov.

and Dec.
1878. V. STERKI, Beitrage zur Morphologic der Oxytrichinae. 'Zeit. Wiss. Zool.,'

Bd. xxxi. Hft. i.
1878. F. STEIN, Der Organismus der Infusionsthiere. Abth. iii. Der Organismus der

Flagellaten oder Geisselinfusorien. Halfte i. Leipzig.
1878. J. VAN REES, Ueber einige Falle von Parasitismus bei Infusorien. 'Zeit. Wiss.

Zool.,' Bd. xxxi. pp. 473-81.
1878. , Parasitism amongst Infusoria. 'Archiv fur Mikroskopische Anatomic,'

Bd. xv. p. 252.
1878. EPHRAIM CUTTER, Rhizopods (Asthmatos ciliaris} a cause of disease. 'Virginia

Medical Monthly,' November.
1878. SURIRAY, Sur la reproduction gemmipare et fissipare des Noctiluques. ' Comptes

Rendus,' torn. Ixxxvi. p. 1482.

1878. A. GRUBER, Die Haftorgane der Stentoren. ' Zoologischer Anzeiger,' Bd. i. p. 390.
1878. E. PERCEVAL WRIGHT, Note onPodophryagemmipara. ' Quart. Journ. Mic. Sci.,'

vol. xviii. new ser. p. 105.
1878. W. VIGNAL, Recherches histologiques et physiologiques sur les Noctiluques.

'Trav. Lab. Inst. Coll. France,' p. 197.
1878. LEOP. MAGGI, Sulla natura morphologica dei Distigma. ' R. Instit. Lombard.

Rendic.,' vol. x.
1878. T. W. ENGELMANN, Ueber Gasentwickelung im Protoplasma lebender Protozoen.

'Zool. Anzeiger,' Leipzig, Bd. i. p. 152.
1878. EPHRAIM CUTTER, Rhizopods (Athmatos ciliaris) a cause of Disease. 'Virginia

Medical Monthly,' November 1878.

RELATING TO THE INFUSORIA. 893

1879. H. E. FORREST, The Natural History and Development of the Vorticellidce.

' Midland Naturalist,' vol. ii. April and May.
1879. Jos. LEIDY, On Athmatos ciliaris. 'American Journal of Medical Science,'

p. 85.
1879. CH. ROBIN. Mdmoire sur la structure et la reproduction de quelques Infusoires

tentacule's, suceurs et flagelle's. ' Journ. de 1' Anatomic et Physiologic,' torn. xv.

p. 529. (Abstract, 'Journ. Royal Mic. Soc.,' October 1880.)
1879. G. DU PLESSIS and F. A. FOREL, Infusorian Fauna of Lake Geneva. 'Bull. Soc.

Vaud.,' torn. xvi. pp. 150, 325.

1879. C. M. MAPLESTONE, On Australian Infusoria. 'Quart. Journ. Mic. Soc. Victoria,'

vol. i. p. 15.
1879. A. CERTES, Sur une me'thode de conservation des Infusoires. ' Comptes Rendus,'

torn. Ixxxviii. p. 433.

1879. , Note sur MHaptophrya gigantea Maupas, Infusoire parasite des Batraciens

anoures d'Algdrie. ' Bull, de la Soc. Zool. de France, torn. iv.

1879. H. C. DUNCKER, Ueber Blepharisma lateritia. ' Cams' Zoologischer Anzeiger,'
Jr. ii. p. 260.

1879. G. DU PLESSIS, Premiere note sur les Infusoires due's he'te'rotriques des faunes
littorale et profonde du Ldman. ' Bull. Soc. Vaud. Sc. Nat.,' torn. xvi. p. 160.

1879. P- HALLEZ, Contributions a ITiistoire naturelle des Turbellariens (notice of Tricho-

dina mitra). ' Trav. de 1'Inst. Zoolog. de Lille,' Fasc. ii.
1879. G. ENTZ, Ueber einige Infusorien des Salzteiches zu Szamosfalva. ' Terme'-

szetrazii fiizetek,' vol. iii. p. 219.
1879. A. DODEL-PORT, Infusorien als Befruchtungs-Vermittler bei Florideen. ' Kosmos,'

Bd. iii. pp. 182-90. (Translation, ' Nature,' vol. xx. p. 463.)

1879. E. MAUPAS, Sur la position syste'matique des Volvocine'es, et sur les limites du
regne ve'ge'tal et du regne animal. ' Comptes Rendus,' torn. Ixxxviii. p. 1274.

1879. , Haptophrya gigantea, Opaline nouvelle de 1'intestin des Batraciens anoures

d'Alge'rie. ' Comptes Rendus,' Ixxxviii. p. 921.
1879. , Sur quelques animaux et ve'ge'taux multinucle'e's. ' Comptes Rendus,'

torn. Ixxxix. p. 250.
1879. E- EVERTS, Description d'une Opaline (Opalina discoglossi). 'Tijds. nederl. dierk.

Vereeniging,' Bd. iv. pp. 92-6.
1879. A. GRUBER, Neue Infusorien. 'Zeit. Wiss. Zool.,' Bd. xxxiii. p. 439. (Translation,

'Journ. R. Mic. Soc.,' April 1880.)
1879. SERRANO-FATIGATI, Influence des diverses couleurs sur le deVeloppement et la

respiration des Infusoires. ' Comptes Rendus,' torn. Ixxxix.
1879. G. CATTANEO, Intorno alia anatomia e fisiologia del Podostomafiligerum, C. & L.

' Atti Soc. Ital. Sc. Nat.,' vol. xxi.

1879. L. MAGGI, Intorno alle Cothurnie parassiti delle branchie dei Gamberi nostrali.

' Bull. Scientific.,' i. p. 33.

1880. A. CERTES, Sur 1'analyse micrographique des eaux. ' Comptes Rendus,' torn. xci.

1880. , Sur la glycogdnese chez les Infusoires. ' Comptes Rendus,' torn xc. p. 77.

1880. M. HARTOG, On an undescribed Acinetan (Podophrya infimdibulifera). ' Proc.

Manchester Lit. and Phil. Soc.,' vol. xix. p. 41.
1880. J. A. RYDER, On the occurrence of Freia producta in the Chesapeake Bay.

'American Naturalist,' vol. xiv. p. 810.
1880. LEOP. MAGGI, Sopra una varieta della Cothurnia pyxidiformis D'Udk. 'Bull.

Scientific.,' No. v. p. 69.

LIST OF WORKS RELATING TO THE INFUSORIA.

1880. G. HALLER, Beitrage zur Kenntniss der Loemopodes filiformes. 'Zeit. Wiss.
Zool.,' Bd. xxxiii. p. 395. (Notice of Parasitic Acinetan.)

1880. T. W. ENGELMANN, Zur Anatomic und Physiologic der Flimmerzellen. ' Pfliiger's
Archiv Physiol.,' Bd. xxiii.

1880. J. LEVICK, On Dendrosoma radians. ' Midland Naturalist,' vol. iii., February.

1880. W. SAVILLE KENT, Notes on Marine Infusoria. 'Trans. Birmingham Natural

History Society,' p. 7. (Also ' Midland Naturalist,' April and May 1880.)
1880. , A Manual of the Infusoria, Parts I. and II. Imp. 8vo, London.

1880. B. GRASSI, Dei Protozoi parassiti, e specialmente de quelli che sono nel Uomo.
' Gazz. med. Italo-Lomb.,' torn, xxxix. p. 445.

1880. Jos. LEIDY, On Stentor amethystinus. ' Proc. Acad. Nat. Sci. Philadelphia.'

1 88 1. R. S. BERGH, Der Organismus der Cilioflagellaten. ' Morphologisches Jahrbuch,'

Bd. vii. Hft. 2.
1881. A. GRUBER, Dimorpha nutans, eine Mischform von Flagellaten und Heliozoen.

' Zeit. Wiss. Zool.,' Bd. xxxvi. Hft. 3.
1881. D. D. CUNNINGHAM, Development of Microscopical Organisms in intestinal canal

and faecal evacuations of man, cows, and other animals. ' Quart. Journ. Mic.

Sci.,' N. S. vol. xxi.
1 88 1. CONRAD PARONA, Acineta dibdalteria, nouvelle espece d'Infusoire marin du Golfe

de Genes. ' Archiv. Sc. Phys. et Nat. Geneve.' (Abstract ' Ann. Nat. Hist.,'

March 1881.)
1881. HERMANN FOL, Contribution a la Famille des Tintinnoden. ' Archives des Sc.

Phys. et Nat.,' torn. v. (Translation 'Ann. and Mag. Nat. Hist.,' April 1881.)

1881.. W. BURTON, On a Parasite of Vorticella. 'The Northern Microscopist/ vol. i.
p. 214.

1 88 1. A. CERTES, Sur un proce'de' de coloration des Infusoires et des elements anato-
miques pendant la vie. ' Comptes Rendus,' torn. xcii. p. 424.

1881. W. SAVILLE KENT, Infusoria : What are they? their Collection and Preservation.
' Trans. Epping Forest Naturalists' Field Club,' vol. ii. p. 44.

1881. , The Myxomycetes or Mycetozoa : Animals or Plants? 'Pop. Sci. Rev.,'

N. S. vol. v. No. xvii.

1881. , A Manual of the Infusoria, Parts III., IV., and V. Imp. 8vo, London.

1881. JOSEPH LEIDY, Parasites of the Termites. ' Proc. and Journ. Acad. Nat. Sci.
Philadelphia, vol. viii.

1881. G. E. DAVIS, A piece of weed and something on it. (Notice of New Species

of Salpingceca.) ' The Northern Microscopist,' vol. i. p. 3.

1881. JOHN TYNDALL, Essays on the Floating Matter of the Air. 8vo, London.
1881. F. W. PHILLIPS, On a Species of Chatospira found at Hoddesdon. ' Trans.

Hertfordshire Nat. Hist. Soc.,' vol. i. part v.
1881. PATRICK GEDDES, On Pulsatella convolutce. ' Comptes Rendus,' torn, xciii.

1 88 1. J. KUENSTLER, Sur la Kunckelia gyrans, une nouvelle espece d'Infusoires.
' Comptes Rendus,' torn, xciii.

1881. ALEXANDRE FQETTINGER, Recherches sur quelques Infusoires nouveaux, parasites

des Cephalopodes. ' Archives de Biologic,' torn, ii., et ' Bull. Acad. Royale
Belgique.'

1882. J. L. DE LANESSAN, Traite de Zoologie (Protozoaires). Roy. 8vo, Paris.
1882. W. SAVILLE KENT, A Manual of the Infusoria, Part. VI. Imp. 8vo, London.

CORRIGENDA.

Vol. I. p. 77, line 2 from bottom, for " PL XLIX." read " PL L."

„ 210, line 4 from top, for " Hoplophrya and Haplophrya" read " Hoplitophrya
and Haptophrya?

„ 21$, line 12 from top, for " DYSTERI ADJE " read " DYSTERIID^E."

„ „ line 7 from bottom, to Family Acinetidae add Genus Sphcerophrya.

„ 252, line 22 „ for " obliquus " read " obliqua."

„ 253, line 8 „ for " rostratum " read " rostrata."

„ 254, line 26 „ for " quadratum " read " quadrata."

„ 259, line 19 from top, for "typicus" read "typica."

„ 272, line ii from bottom, for "casspitosa" read " caespitosum." Also in

Explanation of Plates XVII. and XVIII.
„ 280, line 3 from top, for « PL XL" read " PL XII."

» » line J3 » » »

„ „ line 12 from bottom, „ „

„ 287, line 12 from top, „ ,,

„ „ line 12 from bottom, „ „

„ 298, line 13 from top, for " distortum " read "distorta."

„ 300, line 8 from bottom, for " consociatum " read " consociata."

„ 301, line 5 „ for "the ordinary phytozoa" read "ordinary proto-

phytes."

„ 305, footnote No. 2, for " Bd. ii." read " Bd. vi."

„ 312, line 12 from top, for "marina" read "marinus." Also in Explanation of

Plate XIX.

„ 323, line 15 from bottom, for " polyflagellate " read " multiflagellate."

„ 328, footnote, for " Bd. xxxi." read " Bd. xxxii."

» 395» lme 7 from bottom, for " C. arbusculum" read " C. arbuscula"

„ 419, line 13 from bottom, for " C. cordata " read " C. cordiformis."

„ 422, line 3 from bottom, for " tuberculatus " read " tuberculata."

„ 429, footnote No. i, for " 1878 " read " 1868."

„ 438, line 15 from top, for " octocostatus " read " octocostata."

• „ 451, line 9 from bottom, for "aequalis" read "aequale." Also in Explanation
of Plate XXV.

„ 462, line 19 from bottom, for " cornutum " read " cornutus."
Vol. II. p. 488, line 17 from top, for " marina" read "marinum."

„ 498, first line, for " microstomum " read " microstoma." Also in Explanation
of Plate XXVI.

896 CORRIGENDA.

Vol. II. p. 520, footnote No. i, for " Bd. xxxv." read " Bd. xxxii."

„ 561, footnote, for " Morphologische " read " Morphologisches."
„ 600, first line, for " sty lifer " read " stylifera."
„ 6 1 1, line 13 from bottom, for " fluviatilis " read " fluviatile."
,, 612, line 12 from top, for " semiciliatus " read " semiciliatum."

„ 623, line 5 from bottom, for " Sub-Fam. 3. ORPHRYDINA " read " Sub. Fam. 3.
OPHRYDINA."

„ 650, line 9 from top, for " 1-1600" " read " 1-600"."
„ 654, in footnote, for " Bd. iv." read " Bd. xi. Hft. 4."
„ 660, line 4 from bottom, for " Bd. ii." read " Bd. xi."

„ 676, line 13 from bottom, for " Vorticella fluviatilis" read " Vorticella fluvi-
alis."

„ 700, line 19 from top, for " Figs. 17-20" read " 17-19."
„ „ line 6 from bottom, for " sedendary " read " sedentary."

„ 709, footnote No. I, for " Bd. xxxix." read " Bd. xxix."
„ 780, line 5 from top, for " gibba" read "gibbus."

„ „ 13 lines from bottom, for " Uroleptus ratulus " read " Uroleptus raHulus"

Vol. III. Explanation of PL XXVIII., for " PYRSONYMPHA " read " PYRSONEMA."

„ PI. XXXIV. Figs. 5 and 6. — Transverse striation of cuticle of Rhabdostyla ovum
accidentally omitted by the artist.

„ „ Figs. 23 and 24. — Transverse striation of cuticle of Vorticella

putrinum similarly omitted.

INDEX.

[Synonyms ar< printed in Italics.]

Acarella ,

„ siro .. ..

Acidophorus ..

Acineria acuta
„ incurvata

Acineta

„ compressa
Acineta cothurnata ..
Acineta cothurnia ..

„ crenata

,, cucullus ..
Acineta diademiformis ..
Acineta dibdalteria
Acineta digitata ..

„ divisa

„ emaciata ..

„ fcetida

„ grandis ..
Acineta hyphydri

„ infusionum
Acineta Jolyi ..

„ lemnaruni . .
Acineta ligulata ..
Acineta linguifera ..

„ livadiana ..
Acineta Lyngbyi ..
Acineta mystacina..

„ notonectae

„ patula
Acineta phryganidarum
Acineta poculum ..

„ pusilla
Acineta quadriloba

„ Saifulae
Acineta socialis
Acineta stellata

„ tuberosa ..

„ vorticelloides

Acinetopsis

„ rara
Acomia cyclidium ..

Actinobolidaa

Actinobolus

„ radians

Actinocyathus

„ cidaris ..

Actinolophus pedunculatus
Actinomonadidie ..
Actinomonas .

817

636
636

494
527
527
828

833
815

833
837
832

8£5

839
812
836
837
832

831
818
819

835
830
832

831
828
815
834
833
835
819

833
837
820
836

335
838
829
837
855
855
546
630
630
630

Actinomonas mirabilis . .

„ pusilla

Actinophrys

A ctinophrys pedicellata
Actinophrys sol
Actinotricha

„ saltans

.tfigyria

„ angustata ..
„ fluviatilis
&gyria legumen ..
ALgyria. monostyla ..

„ oliva

„ pusilla

A las tor polypormn

Allotricha

„ mollis
Alyscum saltans ..
Amblyophis

„ aegyptiaca ..

„ viridis ..

Amoeba lacerata
Amoeba monociliata
Amoeba radiosa
Amoeba rotator ia ..

„ -uillosa
Amphidinium

„ operculatum
Amphileptus

„ anas ..

„ anaticula ..

„ anser..

„ cygnus ..

Amphileptus fasciola ..
Amphileptus gigas..

„ gutta .. ..

„ longicollis . .

„ margaritifer

„ meleagris ..

Amphileptus meleagris
Amphileptus moniliger ..
A mphileptus papillosus
Amphileptus sphagni t..

„ vorax

Amphimonadidae ..

Amphimonas

Amphimonas brachiata..

„ can data .,

„ dispar

227
227
225
813
376
790

790
755
755
756

755
755
756
756
764
782
782
545
385
386
386

222
222
225
220
221
461
461

523
524
526

525
524

743
£24

.. 526

.. 525

.. 526

.. 528

.. 525

.. 527

.. 527

.. 525

.. 280

.. 280

.. 281

281, 432
281

2 F

INDEX.

Amphimonas divaricans

PAGE
.. 282

Astasia

PAGE

vi e

exilis

.. 282

Astasia acus

„ globosa

.. 28l
767

„ crassa
Astasia contorta ..

.. 378

,, gibba
„ Kessleri
„ pernix
„ velox

.. 767
.. 768
.. 768
.. 768

Astasia costata
„ deformis
Astasia flavicans
Astasia flavicans
„ fusiformis

.. 858

.. 378

-• 377

.. 418
378

„ injlata

777

Anisonema acinus
„ coricavum
Anisonema grande

•• 435
.- 435
• • 434
437

„ limpida
Astasia longifilis
„ pusilla
Astasia pusilla

.. 376

•• 377
•• 377
.. 418

„ intermedium
„ ludibundum
„ quadricostatum .

.. 436
.. 436

„ regularis
Astasia trichophora

- 378
•• 376
378

Anisonema sulcata

437

„ utriculus

777

Anisonema truncatum ..- . ..

A36

Anisonemida^

4.2Q

.. 466

Anophrys

CI I

,, ciliaris

467

„ sarcophaga . ..

34,1

Anoplophrya

,, disjuncta

branchiarum

61:4,

„ clavata
cochleariformis

566
566

,, fallax
Atractonema . . . . . . . .

.. 654

„ convexa
„ filum
„ inermis

- 567
- 567

„ teres

•• 373

„ mytili
„ naidos
,, nodulata ..

.. 565
- 563

„ remigens
Bacterium rubescens
Balantidium

.. 546

.. 245

S77

„ ovata
, pachydrili
, prolifera
, socialis
, striata
, vermicularis ..
Anthophysa
Anthophysa Bennetti

.. 567
.. 568
476, 564
.. 566
.. 565
.. 566
.. 266
.. 266

coli
duodeni
elongatum
entozoon
medusarum
Benedenia coronata
„ elegans
Bicososca

.. 578
.. 578

- 577
• • 577
.. 578
.. 860
.. 860

274.

„ caspitosa
„ Mulleri ..

.. 272
267

„ gracillipes
„ lacustris

.. 276

Anthophysa socialis
Anthophysa solitaria

272
334.

„ pocillum
Bicososca socialis

.. 277
2QO

Anthophysa vegetans

Bicosceca tenuis

276

Aporea ambigua

28;

Bikcecidse

273

Arachnella

86 1

637

Blepharisma hyalinum

eg.

„ bipartitum
„ convolutum
„ globosum
Archimedea remex

.. 638
.. 638
•• 637

6O3 777

Blepharisma lateritia
Blepharisma per sicinum
Blepharisma undulans
Bodo

.. 585
.. 585
- 585

Ascetta primordialis

186

432

Ascoglena

Bodo colubrorum

257

,, vaginicola
Aspidisca

•• 393

7Q2

Bodo globosus
gracilis .. .. . . .. . .

.. 295
2QQ

„ Andrewii

7Q4.

43 S

Aspidisca cicada

7Q4.

Aspidisca costata

7Q4.

2;6

„ hexeris
,, lyncaster .. ..

•• 793

7Q3

intestinalis

.. 255

„ lynceus

257

„ polystyla '
„ sedigita
„ turrita

•• 793
•• 793
•• 793

maximus
melolonthae
Bodo musccE-domesticce

.. 257
.. 257
.. 245

INDEX.

899

Bodo muscarum

PAGE

.. .. 257

Bodo ranarum

.. .. 256

2CC

Bodo urinarius

.. .. 258

Bursaria

Bursaria decora

.. .. 576-

.. ?6i

585

4Q7

S77

,, patula

. .. 588

Bursaria truncatella
Bursaria vernalis
„ virens
„ vorticella

Calceolidae

.. .. 576

.. .. 497
.. .. 588
.. .. 576

.. .. 618

.. .. 618

„ cypripedium ..
Callodictyon

477, 619, 642

-1Q7

"}O7

Campylopus paradoxus
Carchesium

•• • • 797

6OO

„ aselli
„ epistylidis ..
„ Lachmanni
„ polypinum

.. .. 693
.. 692
.. 691
690

„ . septatum
Carchesium spectabile ..
Catallactidae

. .. 693
.. 691

Cephalothamnium
„ caespitosum
„ cuneatum
Cephalothamnium cyclopum
Ceratium

.. .. 272
.. .. 272
.. .. 273
.. .. 273

452

„ biceps
„ bicorne
,, candelabrum ..

.. .. 455

.. .. 456
4.62

4.^4

Ceratium delitiense

dCC

Ceratium divergens

.. . 453

4cc

456

Ceratium hirudinella
Ceratium hirundinella

.. 462
. .. 859

4c8

,, longicorne

457

Ceratium macroceras
Ceratium Michaelis
,, pyrophorum ..
Ceratium pyrophorum ..

. .. 457
• .. 453
• • •• 453
.. .. 455

457

„ trichoceros
„ tridens
„ tripos
Cercaria pleuronectes ..
,, tripos

.. .. 457
- •• 453
• • -. 454
.. .. 387
.. .. 454

Cercaria turbo .. .,
Cercomonadidae
Cercomonas

Cercomonas acuminata . .
Cercomonas crassicauda
Cercomonas cur-vata
Cercomonas cylindrica ..
Cercomonas detracta

„ facula
Cercomonas fusiformis ..

„ globulus ..

Cercomonas hominis

„ intestinalis . .

„ lacryma

„ lobata

Cercomonas longicauda
Cercomonas muscte-domesticce

,, tnuscarum ..

„ obesa ......

„ ramulosa .. ..

„ ranarum

,, termo ......

„ truncata
Cercomonas typica
Cercomonas viridis

„ -vorticellaris
Chiztoglena ........

„ caudaia

„ volvocina ..
Chaetospira ........

Chcetospira cylindracea ..

„ marina
Chaetospira mucicola

„ t Mulleri
Chtztospira remex ......

Chcetotyphla ........

„ armata

„ aspera

Chasmatostoma ......

„ reniforme ..

Chilodon ..........

„ cucullulus
„ propellens
Chilodon uncinatus
Chilomonadidae ......

Chilomonas ........

„ amygdalum

„ cylindrica ..

Chilomonas granulosa ..

„ obliqua
Chilomonas paramaecium
Chlamydodon ........

„ Mnemosyne ..

Chlamydodontidae ......

Chlorangium ........

„ stentorinum

Chloraster ........

» agilis ......

„ gyrans ......

„ tetrarhynchus
Chloromonas ........

642
249
258
261
260
261
260
261
261
260
260
256

2I5
261

261
259

245
245
236

235
261

253
261

259
261
261
389

.. 390

.. 601

.. 778

.. 602

.. 602

.. 602

603, 777

.. 389

•• 39i

•• 391

.. 540

.. 540

.. 746

.. 746

... 860

•• 747

•• 423

- 423
.. 426
.. 425
.. 424
.. 424
.. 424
.. 750
.. 750

- 745
.. 407
.. 407
.. 315
.. 317

» ,
Chloropeltif

„ hispidula

2 F 2

401
401
387
388
388

900

INDEX.

Choano-Flagellata

Choenia

» teres ..

Chcenia vorax

Chonemonas hispida
, , Schratikii

Chrysomonadidas

Chrysomonas

„ flavicans ..

„ ochracea..

Chrysopyxis

„ bipes

Chytridium ampullaceum
Chytridium Steinii

Ciliata

„ -Heterotricha
„ -Holotricha
„ -Hypotricha

„ -Peritricha

Cilio-Flagellata

Cinttrochilum margaritaceum

Cladomonas

„ fruticulosa

Cladonema

„ laxa

Class Ciliata

„ Flagellata

„ Tentaculifera
Classification of Infusoria

Coccudina costata

Codonella

„ campanella .. ..

„ galea

„ orthoceras ..

Codonellidas

Codonocladium umbellatum . .
Codonodesmus phalanx . .

Codonceca

„ costata

„ inclinata

Codonosigidae

Codosiga

„ allioides

„ assimilis

„ botrytis

„ candelabrum ..

„ cymosa

Codosiga echinata

Codosiga furcata

„ grossularia
,, pyriformis
Codosiga pulcherrima ..
Codosiga Steinii .. .....'

„ umbellata

Coelomonas

„ grandis .. ...
Ccenomorpha medusula..

Colacium ...

arbuscula

calvum

multoculata ..

Steinii

vesiculosum ..

Colepidae

Coleps

.. 324

.. 521

.. 521

.. 521

.. 390

.. 39°

.. 401
.. -402
402
402

.. 408

.. 408

• • 345
.. 639

•• 473

•• 575

.. 484

•• 739
622, 623

439. 440

.. 794

.. 284

.. 284

.. 264

.. 265

•• 473

.. 216

.. 801
195-215

•• 794

.. 615

.. 616

.. 616

.. 616

.. 615

•- 336

.. 342

.. 261
261

.. 261

.. 329

•• 333

•• 337

.. 340

•• 334

•• 339

•• 337

•• 334

•• 339

•• 338

•• 339

• 334
.. 340

•• 335

.. 392

•• 393

.. 641

• • 393
•• 394
•• 395
•• 396
•• 395
•• 359

506

Coleps amphacanthus ..

Coleps elongatus

Coleps fusus

„ hirtus

„ incurvus

Coleps inermis .. .. ..

Coleps uncinatus

Coleps viridis

Colouring Infusoria during Life
Colpidium

„ cucullus

Colpoda

Colpoda cuculio
„ cucullulus .
„ cucullus
Colpoda cucullus
,, parvifrons .
„ pigerrima
Colpodella ,

„ pugnax

Colponema ,

„ loxodes

Conchophthirus

„ anodontae .,

,, curtus ..

„ Steenstrupii

Condylostoma

„ patens ..
Condylostoma patulum
Condylostoma stagnate
Corethra sertularia
Cothurnia

„ arenata

„ astaci

„ Cohnii

„ compressa .. .
Cothurnia corrugata ..
Cothurnia curva

„ elongata
Cothurnia fur cifer

„ gigantea .. .
Cothurnia gracilis

„ havniensis ..

„ imberbis .. .

„ irregularis

,. maritima

„ nodosa

Cothurnia operculata ..

„ operculigera . .
Cothurnia ovata .. .. .

„ patula

„ pontica

„ pupa

Cothurnia pyxidiformis
Cothurnia recurva
Cothurnia Sieboldii

Cothurnia socialis ,

Cothurnia spissa

Cricocoleps

Cryptobia helicis

Cryptoglena

„ angulosa ..

Cryptoglena caruleus ..
Cryptoglena conica
Cryptoglena cordiformis

508
506
507
506
508
508
507
506
862
537
537
512

747
747
537
512

513
513
378
378

297
279
490
490
491
490
584
5.84
584
584
849
719
725
721

723
722
728
721

723
727
716

724
720
720

723
720
721
719
726
722
722

725
724
726
721
720
728

723
506
256
419
420
420
419
315

INDEX.

901

Cryptoglena lenticularis
„ pigra .. ..

Cryptomonas

Cryptomonas curvata ..
Cryptomonas erosa

„ ovata
Cryptomonas polymorpha
Cyathomonas

„ alba..

„ elongata ..

„ emarginata

„ lychnus ..

„ spissa

„ turbinata

„ turbo

„ viridis

Cyclidium

Cyclidium abscissum
Cyclidium arboreum
„ citrellus..
Cyclidium ClaparZdi
„ crassum
„ elongatum
Cyclidium glaucoma
Cyclidium margaritaceum
„ nodulosum ..

Cyclochaeta

„ spongillae . .
Cyclogramma rubens
Cyclotricha

„ citrea ..
Cypridium

„ aculeatum . . .

„ crassipes

„ lanceolatum ..

„ spinigerum, ..

Cyrtostomum

leucas

Dallingeria

„ Drysdali
Deltomonas

„ cyclopum ..

Dendrocometes

,, paradoxus

Dendromonadidae ..

Dendromonas

„ pusilla
„ virgaria ..
Dendrosoma

„ astaci . .

„ radians
Desmarella

„ moniliformis

,, phalanx

Dictyocoleps

Dictyocysta

„ acuminata

„ cassis

,, elegans

„ lepida..

„ mitra ..

,, templum

„ tiara ..
Dictyocystidae..

PAGE

4IQ

PAGE

.. 481

4O2

.. 480

4O4

.. .. 638

404
404
404

425
241
242
243

„ nasutum
Dileptus folium

» gig115
„ granulosus
Dimastigoaulax
,-, cornutus

.. 476, 639

.. » 743
.. - 524
.. .. 527
.. 462
.. 462
.. .. 856

243
242
242

242

„ mutans
Dinamoeba mirabilis
Dinema griseolum

.. .. 856

.. 221

.. .. 437

242

555

242
544

„ gracilis .. ..

.. - 555

4OQ

371

545
545
545
372
549
544

Dinobryon gracile
Dinobryon juniperinum
Dinobryon petiolatum ..
Dinobryon sertularia
Dinobryon sociale
Dinobryon stipitatum ..

.. .. 4"

.. .. 412
.. 278,411
.. .. 409
.. .. 4"
.. 410

421

794
372
6;o

„ tuberculata
„ vorax
Dinophysis

.. 422

.. 235, 422

458

650
495
535
535
754
754
755
754
754
496
497

•JOQ

„ acuminata ..
, acuta
, arctica ..
, atlantica
, caudata
, laevis
, Michaelis ..
, norvegica ..
, ovata
Dinophysis rotundata ..
„ ventricosa ..
Diophrys marina
Diplomastix

.. .. 459
.. .. 459
.. 460

.. - 459
460
. . 460
.. •• 459
.. .. 459
.. 460
.. 460

• • •• 459

.. .. 800

4.71

310
283
283

8lO

„ affinis
„ caudata

„ salt an s

• • •• 433
.. .. 432

.'. •• 433
.. 289

839
262
26?

Diplomita insignis
Diplomita socialis
Diplopsalis

.. •• 435
.. .. 289
gcg

266
266

„ lenticula
Diploselmis

.. .. 859

4.^?

840
84;

Discocephalus rotator ius

.. .. 800
.. 568

841

Discostomata

W

341

14.2

Discostomata-Gymnozoida ..
Discostomata-Sarcocrypta ..

.. .. 3|5
.. .. 365
.. 4l8

506
624
627
624
626
626
625
62?

„ proteus
Distigma proteus
„ tenax
„ viridis

Drepanomonas dentata ..
Drepanostoma striata ..
Drepanostomum pectinatum

.. .. 418
.. .. 418
.. 418
.. .. 418

.. .. 744
.. .. 748
.. .. 861

752

626
624

Dysteria aculeata
Dysteria armata

.. .. 755
.. 478,752

9O2

INDEX.

PAGE

Dysteria crassipes

.. .. 755

Epi

„ lanceolata

.. .. 754

Erz

„ spinigera

.. .. 754

i

Dysteriidae

.. 751

t;oQ

i
Euc

^o^

„ elongatus . .

.. .. 504

Enchelyodon elongatus ..

.. .. 521

Enchelyodon farctus

.. .. 503

Enchelys

COQ

„ arcuata

.. .. 510

Enchelys corrugatiim ..

.. .. '546

Euc

Enchelys farcimen

.. .. 510

Eug

pupa

.. .. 510

Enchelys pyriformis

.. .. 536

„ triquetra

.. .. 545

.. .. 808

653

4^7

Eut

„ sulcatus

.. .. 438

V

.. .. 846

Euc

Ephelota apiculosa

.. .. 847

•"•f
Eu±

Ephelota coronata

.. .. 846

Trold

.. .. 847

77^

EUE

„ auricularis ..

•• •• 773

*•*»!

Eu±

„ radiosa

.. .. 774

EU£

„ retractilis

.. .. 774

Eu±

EUE

„ utriculus

.. .. 409

j

Epistylis

7oo

Eut

„ anastatica

701

Eu£

Epistylis arabica

710

Epistylis articulata

.. 701

EUJ

„ balanorum

.. .. 709

EUJ

„ barba

.. .. 709

Euj

Epistylis berberiformis

.. .. 712

Ert±

„ botrytis

• • 334,709

Eu]

Epistylis branchiopyla ..

.. .. 705

EuA

Epistylis brevipes

.. .. 665

Eu;

Epistylis coarctata

. . 706

„ crassicollis

.. .. 705

Eu^

„ digitalis

.. .. 704

Eu

„ euchlora

.. .. 709

Eu

„ flavicans

.. 702

Eu

galea

701

Eu

Epistylis grandis

702

Eu

„ hospes

.. .. 7H

Eu

Epistylis invaginata

.. 706

„ leucoa

.. .. 704

Epistylis minutus

.. 710

Fei

„ nebulifera

.. .. 665

Fla

Epistylis nympharum ..

.. .. 708

„ pavonina

.. .. 709

„ plicatilis

701

Epistylis pusilla

.. .. 266

Fol

Epistylis pyriformis

.. .. 707

Epistylis ringens

.. .. 666

„ sphcer aides

.. .. 666

Epistylis Steinii

.. .. 708

., tubificis

.. .. 707

Epistylis umbellatus

.. .. 336

Epistylis umbilicata

.. 706

Foi

Epistylis vegetans

710

Fr

Epistylis virgaria ..
Ervtlia fluviatilis ..
legumen
monostyla ..
lia

Bcekmanni ..

Gegenbauri . .

Kollikeri ..

Krohnii

Leydigii

Mulleri

Virchowii . .
aidse

acus

agilis
deses
fusiformis

feniculata
ispidula.. ' ..

hyalina ..
Euglena longicauda
Euglena mucronata

obscura ..

ovum

Euglena oxyuris
Euglena pyrum
Euglena rostrata
Euglena sanguinea
Euglena spirogyra ..

Supplementary
Euglena triqueter ..
Euglena tuba

viridis
Euglena zonalis

Euglenidae

Euplotes

Euplotes appendiculatus
Euplotes charon
Euplotes excavatus
Euplotes harpa

longipes

Euplotes monostyla
Euplotes patella

Euplotidae

Eustomata

Eustomata-Dimastiga ..
Eu stomata- M onomastiga

ia

viridis ..

266
756
755
755
228
228
228
228
228
228
228
228
228
379
383
384
383
384
384
388
38i
387
385
385
388

383
387
384
38i
382

385
387
385
38i
388

379
797
800

799
800

799
799
755
798
792

35
401

367
.416
416

Fertilization of Seaweeds by Infusoria 862

Flagellata 216,856

-Discostomata 324

-Eustomata 366

-Pantostomata 229

la 596

ampulla 597

Boltoni 600

elegans 598

hirundo 600

producta .. 599

stylifera 600

Foraminifera 45

597

INDEX.

903

Freia aculeata

PAGE

cg8

PAGE
.. 501

„ Americana
,, ampulla . . . . . .

.. .. 598
eo8

„ oblonga

.. SOI

.. 442

"»99

„ nasutum

• • 442

Frontonia, leucas ,

yyy

4.QO

.. 822

\
Gastrophysema dithalamium

160

.. .. 783

Benedeni
crustaceorum ..
gemmipara

.. 824
.. 826
.. 823

„ setifera
„ Steinii
General History of Infusoria
Gerda

.. .. 784 '
.. .. 784
.. .. 1-30
657

microsoma
pusilla
Thouleti
truncata

.. 825
.. 826
.. 826
.. 825

,, fixa

,
6S7

Herpetomonas

.. 245

srlans

657

}) Lewis!

.. 245

Gerda indinans
Glaucoma

.. .. 660

7<X .

„ muscae-domesticae

.. 245
.. 463

„ margaritaceum
scintillans .

.. .. 796

7QC

Heteromastigidae

.. 463
463

Glaucoma Wrzesniowskii ..
Glenodinium

.. .. 533

AAO

„ proteiformis ..

.. 463

2QO

„ acuminatum
„ cinctum ..
„ Warmingii
Glenopolytoma typicum
Glycogen in Infusoria .. ..

.. .. 446
.. .. 446
.. .. 859
.. .. 304
863

„' adunca
„ amyli
Heteromita angustata
„ crassa

.. 297
.. 296
.. 298

• • 435

297

Glyphidium marinum . ,

4.26

' f
29O

Goniomonas • •

280

29 C

truncata •

280

292

Gonostomum affinis .. ..

772

291

4.6^

,, ovata .

29?

Grantia ciliata . , ,.

177

' f
2QO

1?^

293

Gymnodinium .

AA.2

,, sulcata .. .. ..

296

Gymnodinium apiculatum ..
Gyninodinium corpusculum . .

~ • 449

AA-i

„ uncinata

.. 294
29O

fuscuni . . «

AA-i

4^O

eracile

858

acus

43O

„ Lachmanni ..
„ marinum
„ monadicum . .
„ pulvisculus

.. . 444
.. . 444
•• •• 443
443

„ globuliferum
„ marina
„ pusillum
Heterotricha

.. 430
.. 431
- 431

.. 573

„ roseolum . .

MA.

318

„ spirale ..

.. .. 858
64.0

„ infiata
„ intestinalis ..

•• 319
.. 3J8

64.0

,, nodulosa .. ..

321

„ oxyura

.. 640

„ rostrata
Hexamitidae

320
.. 318

Habrodon curvatus
Haliphysema Tumanowiczii ..
Halisarca lobularis . . ..

.. .. 494
.. 160
169, 335

Himantophorus char on
Histology and Physiology

.. SCO
.. 862
789

Halteria .. .•»

.. 631

,, similis

789

Halteria bipartita

.. .. 633

.. 789

Halteria grandinella

501;, 632

498

„ lobata
Halteria pulex
Halteria verrucosa
„ viridis
„ volvox
Halteriidgj

.. - 633
.. .. 636
.. .. 632
.. 632
.... 632
6^0

„ brunnea
, coleps
, discolor
, Kessleri
, lateralis
, ovum .. . .

.. 499
.. 508

•• 499
.. 499
.. 500
4.98

568

Holophrya ovum .. ..

;n

„ gigantea .. ..
„ planariarum . .

.. .. 569
.. .. 568

Holophrya tarda
Holosticha

.. 499
769

„ tritonis

•-.. .. 571

274.

„ flava
„ mystacea

.. 769
760

„ bulla

.. .. 274

„ oculata

.. 770

904

INDEX.

Holosticha rubra

PAGE
77O

Lembadion

PAGE

1^6

„ Wrzesniowskii ..
Holotricha
„ -Astomata ..

.. .. 771

.. 482, 484
1l6

„ bullinum
Lembadion duriusculum

• • • • 537
- •• 537
14.7

Hoplitophrya

Lembus ..

147

Hoplitophrya armata ..
Hoplitophrya falcifera ..
lumbrici
pungens ..
recurva

•• -. 571

.. - "57i
.. - 57i

.. .. 572

„ elongatus
„ pusillus
„ subulatus
„ velifer
Leptodiscus

.. .. 549
.. .. 548
.. .. 548

•• - 547
400

secans
securiformis

.. .. 572

172

„ medusoides
Leptomonas

.. 400

24. •*

, uncinata ..
Huxleya

.. .. 571

717

„ Butschlii ..

Leucophrya nodulata

.. .. 243
164.

„ crassa
Huxleya sulcata

.. .. 758
7^7

„ signata
Leucophrys

.. .. 501
187

Hydra convallaria
Hymenomonas
„ roseola ..
Hypotricha

.. .. 687
.. .. 408
.. .. 408

Leucophrys anodontce ..
„ carnium
„ clavata
cochleariformis

..' .. 490
.. - 536
.. .. 566
166

Ichthyophthirius
„ multifiliis
Iduna

.. .. 530
.. .. 530

712

„ entozoon
„ nodulata
Leucophrys patula
Leucophrys striata

.. .. 577
.. .. 565
.. .. 587
.. 161

„ sulcata

712

Leucosolenia botryoides ..

177

Isotricha

AQ7

,, coriacea . . ..

177

„ intestinalis

4Q7

Licnophora .. -

.. .. 611

„ microstoma ..
„ prostoma

.. .. 498

.. .. 497

„ Auerbachii ..
„ Cohnii

.. .. 651
.. .. 652

74.2

Kerona

763

74.2

Kerona histrio
Kerona polyporum
Kolpoda cucullus
„ pirum
Kiinckelia gyrans

.. .. 789
.. .. 763
•• M 537
.. .. 536
.. .. 857

„ diaphanus
„ fasciola
Litonotus folium
Litonotus varsaviensis ..
„ Wrzesniowskii
Lophomonas

.. .. 745
•• •• 743
.. •• 743
.. .. 744
.. .. 742

321

„ blattarum . .

^21

Lacrymaria

,, striata

^22

„ Cohnii
,, coronata

" " III

Lophomonadidae

.. .. 321

488

Lacrymaria elegans
far eta ..

.. .. 520

117

„ granulosus
„ luridus .. ..

.. .. 489
.. 480

.. gutia . .

117

.. 748

Lacrymaria lagenula
Lacrymaria olor
„ Proteus
„ rugosa .. ..
„ tornatilis ..
„ versa '.tills ..
Lagenella

•• •• 517
.. .. 517
.. .. 517
.. .. 517
•• •• 517

Loxodes brevis
bursaria
cithara
cuculio
cucullulus
dentatus
Loxodes rostrum

.. .. 747
.. .. 487
.. .. 585
.. .. 747
.. .. 747
.. .. 747
748

„ acuminata

•3QI

Loxophyllum ..

127

„ euchlora
Lagenceca

.. .- 39°

Loxophyllum amphilepttis ..
Loxophyllum armatum ..

• • •• 743
?20

„ cuspidata
Lagenophrys

.. 360

, lamella
, meleagris ..

.. .. 529
.. 128

„ ampulla ..
„ nassa
„ vaginicola
Lagotia atro-purpurea ..
„ hyalina

•• •• 733
•• - 733
•• •• 733
.. .. 598
1Q8

, rostratum . .
, setigerum . '.
, Wrzesniowskii

Magosphaera

.. .. 529
.. .. 530

.. .. 528

32^

„ viridis
Lagynus

.. .. 598
120

„ planula
Mallomonadidae

.. .- 323
464

„ elegans .

121

Alallomonas .. .. ..

4.64.

„ laevis

.. .. 521

„ Fresenii ..

.. .. 465

INDEX.

905

Mallomonas Plosslii '
Maryna

„ socialis .. . .

PAGE
412, 464
.. 520
52O

Monas globulus
Monas grandis

PAGE

.. .. .. 239
393

241

Mastigamceba ..
aspera

.. 221
221

„ hyalina

240
241

„ monociliata ..
„ ramulosa
„ simplex
Melodinium

.. 222
.. 222
.. 221

/I45

„ intestinalis ..
Monas irregularis ..
„ Kolpoda
lamellula

256
236
238
238

„ ruberrimum

.. 445

Monas lens

2Q1

Meniscostomum

"H9

„ stomioptycha

C-JQ

374

,, nodosa .

23Q

„ pellucidum

•• 374

„ Oberhauserii
obesa

2l6

„ bacillata
Mesodinium .. .. .. ••

.. 249
63?

„ oblonga
Monas ochracea

237

AO^

„ acarus
pulex

"j>

- <3I
.. 636

„ Okeni
Monas ovalis

.. .. 238, 240
238

.. 783

,, ovata .. .. ..

24O

?II

Monas ovum .. .. .

770

„ truncata
Metopides

.. 511

582

Monas parasitica ..
Monas piscatorum ,,

236

241

„ contorta
Metopus

.. 583
"?8i

„ prodigiosa ..
Monas pulvisculum

241

2AO 2O I

Metopus inflatus
Metopus sigmoides
Microcystis Noltii
„ olivacea

.. 582
.. 581
.. 381
.. 381

„ punctum
Monas ramulosa
Monas rotulus

.. 240, 291, 418
235
241

2^0

403

Monas scintillans ..

241

„ monadina

.. 403

Monas semen

3Q2

„ punctifera

.. 403
.. 706

„ simplex
„ socialis , .

24I

24O

Microthorax pusillus
Microthorax sulcatus

ITf*

.. 796
.. 796
460

Monas sphaerica
Monas succissa
,, termo

240

.. .. 235, 240
2CI

„ dubia
Mitra radiosa

.. 469

775

„ truncata

280

Monadidae

.. 232

232

„ urceolaris ..
uva

241

•JO I

Monas varians

2t7

„ astasioides

241

Monas attenuata

237

Manas bipunctata
Monas concava

.. 238
2^7

Monas vivipara

307

Monas consociata
„ consociatum

.. 287
362

Monocystis tenax ..

418

Monas constricta
Monas cor data
„ crepusculum
„ cylindrica
Monas Dallingeri
„ depressa
Monas deses .. ..

.. 237
.. 241
.. 240
.. 240
•• 233
240

371

angustata
brevipes
consociata ..
fusiformis
globosa ..
gracilis ..
longicollis

330
332
330
331
332

331

111

„ Dumalii
Monas elongata

.. 241
.. 237
24.O

ovata
, Steinii ..
Muscle or Nerve-fibres in

JJJ
332
.. .. .. 331

Stylonychia

„ erubescens

240

862

„ excavata
„ farcimen,
„ flavicans

.. 241
.. 241
.. 402
234

Mycetozoa
Myxomycetes

Nassula

42, 187, 192, 470
42, 187, 192, 470

AQA

„ gibbosa
Monas g liscen s
» globosa

.. 239
.. 240

.. 37°

„ ambigua ..
Nassula conica .. ..
„ elegans ..

495
495
495

906

INDEX.

Nassula flava

PAGE

AQC

PAGE

Ophrydina 734

,, lateritia .. ..

4.06

„ microstomata ..
„ ornata
„ rubens
Nephroselmis

ifyu
496

494
495

AOs

Ophrydtum JEdcs 738

Ophrydium Eichornii 737
Ophrydium longipes 737
Ophrydium sessile 738

„ olivacea . .
Nerve-fibres or Muscle in

405

Stylonychia
862

„ versatile .. 735
Ophryodendridae 849
Ophryodendron 849

jj abietinum 850

„ miliaris ..
Noctilucidae

397

^QO

„ Belgicum 853
„ multicapitatum .. .. 854

Nothopleurotricha setifera
Nuclearia simplex ..
Nyctotherus

784
421

C7Q

„ pedicellatum .. .. 852
Ophryodendron pedunculatum .. .. 853
Ophryodendron porcellanum .. .. 852

„ cordiformis
ffvoervanus

580
580

„ sertulariae 851

„ ovalis . .
„ velox ..

580
581

2CO

» atra 532
„ acuminata '. 532
»» caeca 533
Ophryoglena citreum 535

„ mutabilis . .
„ obliqua
„ quadrata . .
„ rostrata
„ Steinii..
„ termo .. ..
Onychaspis polystyla

25O
252
254
253
253
251

7Q-I

„ flavicans 534
„ griseo-virens 533
Ophryoglena oblonga 533
„ Wrzesniowskii 533
Ophryoglenidae 531
Ophryoscolecidae 652

Onychodromus
„ grandis ..
Opalina

766
766

"^8

„ inermis 653
„ Purkynjei 653
Opisthodon 749

„ caudata
,, dimidiata .. ..

->2°
563

.. ?6i

„ niemeccensis 750

Opalina discoglossi
Opalina intestinalis
Opalina lineata
„ Inmbrici ..

.. .. :. 571

562
564

e6c. C7I

„ parallela 785
„ similis 785
Organization of Infusoria .. .. 49-117
Orthonectida 480

„ my lilt .. ..

56«!

Otostoma 50x3

„ naidos
Opalina obtrigona .. ..

.. ... .. 563

562

„ Carter! 500

Opalina planariarum . .
„ polymorpha

569

c6o

„ marina 427
Oxytricha 786

„ pro lifer a ..
Opalina ranarum ..
Opalina recurva ..
„ similis
„ uncinata ..
Opalinidae
Opalinopsis octopi..
„ sepiolae
Opercularia

564
559
573
563
57i
•• 476,48i,556
.. .. .. 860
860
710

„ aeruginosa 787
Oxytricha affinis 772
„ auricularis 773
„ caudata 780
„ crassa 768
Oxytricha fallax 787
„ ferruginea 786
Oxytricha flava 770
fusca 76?

„ arenicola. ..
„ articulata . .
„ berberina . .
„ cylindrata ..
„ hospes
„ Lichtensteinii
„ microstoma
„ nutans
„ stenostoma
Ophidomonas

861
7ii
7ii
7i3
.. .. .. 714
712
713
710
712

244

,, gibba 780
„ Kessleri 769
Oxytricha macrostyla 788
„ micans 787
Oxytricha multipes 765
„ mystacea 769
„ parallela 785
Oxytricha pellionella 786
Oxytricha pernix 768
Oxytricha platystoma 787

„ jenensis ..
„ sanguinea
Ophionella

244
244

T\A

Oxytricha retractilis 774
„ rubra 770
Oxytricha scutellum 788

„ picta

734

„ sordida 788

Oxytricha strenua
„ tubicola
„ urostyla
„ velox

INDi

PAGE
.. 771
.. 789
.. 765
.. 768

75Q

?X.

907

PAGE

• • 443
.. 456
.. 444
.. 444

4.ee

, fiiscum
, fusus
, incequale ..
, inerme
lineatum ..

Pachytrocha ..

720

, macroceros
, monadicum
, monas
, pulvisculus
Peridinium reticulatum ..
„ sanguineum
„ spiniferum ..
„ splendor-maris . .
„ tabulatum ..
Peridinium uberrimum
„ vorticella ..

•• 454
.. 442
.. 444
.. 442
.. 449
.. 450
.. 449
.. 449
.. 448

• • 445
.. 444
UI

,, cothurnoides ..
Panophrys

.. 729
C33

„ chrysalis
Panophrys chrysalis
,, conspicua
„ farcta
Panophrys flava
„ flavicans
Panophrys griseola
„ paramecioides
„ rubra
„ sordida
„ zonalis
Pantostomata . .. .. ..

•• 534
.. 496
•• 534
•• 534
-. 534
.. 534
•• 534
.. 534
496, 534
• • 534
.. 534

„ ovum

. .. 511
. . . 620

7C8

Pantostomata-Dimastiga
„ -Monomastiga
„ -Polymastiga ..
Pantotrichum lagenula

.. 262
• • 232
• • 305
.. 505
4.8 \

Peritromus . . . . . . . • •

7SQ

„ Emmae
Peronospora infestans ..
Petalomonas

• ••• 759
. .. 293

„ abscissa ..
„ ervilia
„ irregularis
„ mediocanellata
„ sinuata ..

• •• 372
• - 373
• •• 371
• -. 372
627

Paramaecium

„ aurelia
„ bursaria
Paramcecium caudatum
„ chrysalis
„ coli

.. 483
.. 486
.. 486
488, 542

„ ampulla ..
„ spiralis
Phacus . ..

.. 627
. . 629
386

.. 488

„ compressum
„ cucullus
Paramaecium glaucum
Paramcccium inversum

.. 583
- 538
.. 488
.. . 488

„ longicaudus
„ pleuronectes
» pyrum
„ triqueter
Phalansteriidae
Phalansterium
„ consociatum..
,, digitatum
Phalansterium intestinum ..
Phascolodon

.. .. 387
. .. 386
.. .. 387
. •• 387
.. 361
.. .. 361
.. .. 362
.. 362
. 287, 361

Paramaecium marinum ..

.. 488

Paramcecium microstomum .

.. 488
S77

488

. 488

Paramcecium stomioptycha .
Paramonadidae

• 540

„ vorticella ..

.. .. 746

deses
„ globosa
„ ovum
„ stellata
Peranema globulosa
„ protracta

•• 371

•• 370
•• 370
•• 370
225,431

•• 375

„ vermicularis ..
„ viridis
Phialonema

.. .. 519
.. .. 519

373

„ cyclostomum
Phyllomitus

•• •• 373

2QQ

„ uhdulans
Physarum tussilaginis ..

.. .. 299

.. .. 470
.. .. 162

Peridinium

AA*7

„ sequale
„ apiculatum
Peridinium arcticum
„ Carolinianum ..
Peridinium chilophaenum
Peridinium cinctum
„ cornutum
„ corpusculum
» cypripedium
„ depressum
„ • diver gens

.. 451
.. 449
.. 454
.. 462

.. 446
.. 462

•• 443
.. 618

•• 453
•• 453

Physomonas . • . . . . . .

„ marina

,, social! s

.. 264
.. 263
506

Placus

48q

„ striatus

.. .. 490

508

„ coleps
Plagiopyla

.. 508

,, Carteri

•• - 538

908

INDEX.

Plagiopyla fusca
,, nasuta

PAGE

•• •• 539
.. .. 538
?8i

Podophrya infusionum ..
,, Leichtensteinii ..
, libera

PAGE
.. .. 8l9

.. .. 818

814

Plagiotoma acuminata ..
„ blattarunt ..
,, later itia .. ..

.. .. 490
.. .. 580
?8*

, limbata
Lyngbyi .. ..

.. .. 816
.. .. 815
.. .. 821

Plagiotoma lumbrici
Plagiotricha . . . . . . •

.. - 583

771

, phryganidarum . .
Podophrya pusilla .. ., ..

.. .. 818
826, 827

„ affinis
,, strenua
Planicola

.. .. 772
.. .. 772

7K

Podophrya pyrum
„ quadripartita
,, Steinii

.. .. 819
.. .. 820
.. .. 815

„ ingenita
Platycola

.. .. 717
711

Podophrya Trold
, truncata .. ..

.. .. 847
825

„ decumbens
, dilatata

- •• 731
711

,, Wrzesniowskii ..

.. .. 817

224

„ gracilis
, longicollis .. ..

.. .. 732
7^2

,, filigerum

.. .. 225

;o8

, mollis
, regularis
, striata

.. .. 731
.. .. 731

712

„ auricularia ..
„ Schwartzii ..

.. .. 859
.. 508, 860
360

, truncata
Platytheca

.. .. 732
.. 262

„ dichotoma

.. .. 360
3?

, micropora .. .

. .. 262

3OI

Pleurochilidium
„ strigilatum ..
Pleuromonadidae
Pleuromonas .

.. .. 540
.. .. 541
.. .. 249
248

Polytoma ocellata
Polytoma uvella
Polytoma virens
Polytomidae ..

.. .. 304

.. 302

.. .. 304

^OI

„ jaculans ..
Pleuronema

.. 249, 270

542

Poteriodendron petiolatum, ..
Preservative Fluid for Infusoria,

.. .. 278

&c. .. 863

,, chrysalis .. ..

54.1

461

Pleuronema citrellus . . ..

545

Pleuronema coronata
Pleuronema crassa .. ,,

.. .. 544

C4.-3

,, vermina

• • .. 549

461

„ cyclidium ..
Pleuronema marina
„ natans
Pleuronemidae .. .. .. ..

.. .. 545
• • •• 543
- •• 543

C/12

„ lima
„ micans ..
Prorocentrum viridis ..

. . 462
.. 461
.. 462

4.QI

782

armatus

402

,, echinata
,, grandis .. ..

.. .. 783
782

edentatus
griseus . . . . . .

- • 493

4Q2

„ lanceolata ..
Pleurotricha setifera .. ..

.. - 783

784.

margaritifer

• 493

4Q1

Plceotia vitrea

•217

niveus

4Q2

Pl&sconia affinis
, , charon

.. .. 800

800

teres

.. .. 492

4QI

„ longiremis
, , radios a

.. .. 800
.. 800

Proterospongia

.. .. 858

418

,, scutum

707 800

PROTISTA

44

, , subrotunda ..

800

.. 8;9

Podocyathus

827

, aceros

.. 859

„ diadema ..

.. .. 827
813

Protococcus chalybius ..
„ turgidus

.. .. 381
.. .. 381

„ astaci
„ Buckei
,, carchesii
,, conipes .. .

.. .. 819
.. .. 822

.. .. 818
Sic

Protomyxomyces coprinarius
Protoperidinium
„ pellucidum

.. .. 472
.. .. 859
.. .. 859
363

,, cothurnata ..
Podophrya crustaceorum ..

x ->

.. .. 815

.. 826

„ Haeckeli

.. .. 363
31

Podophrya1 cyclopum . .

. 818

304

„ cylindrica .. ..
,, elongata
,, ferrum-equinum ..
„ fixa

Podophrya gemmipara . . .

.. .. 814
.. .. 820
.. .. 813
.. .. 813
821

Pseudospora nitellarum
„ parasitica ..
„ volvocis ..
Pseudosporidae

.. 237, 304
.. 236, 304
.. .. 304
.. .. 304
.. .. 762

Podophrya infundibulifera ..

.. .. 816

„ acuminata ..

.. 762

INDEX.

909

Ptychostomum

„ paludinarum

„ saenuridis

Pulsatella convolutae

Pycnobryon socialis

Pyramimonas descissus . .
„ rostrata ..

Pyrocystis fusiformis

Pyrocystis pseudonoctiluca .

Pyronema

Pyrsonema

„ vertens

Pyxicola

54i
86 1

Pyx dium

affinis

Carteri ..

furcifer . .

operculigera

pusilla

pyxidiformis

socialis

cothurnoides
inclinans

Radio- Flagellata ..

Radiolaria

Raphidomonas

„ semen . .
Reptomonas

„ caudata ..
Rhabdostyla

„ brevipes ..

„ longipes ..

„ nebulifera . .

„ ovum..

„ ringens ..

„ sertularium

„ sphaeroides

Rhipidodendron

,, Huxleyi
„ splendidum
Rhizo- Flagellata
Rhizomonas

„ verrucosa ..

Rhodcessa grimselina

Rhopalura

Rhyncheta

„ cyclopum . .

Salpingceca

„ amphora

„ amphoridium

„ ampulla

„ Boltoni

,, campanula..

„ Carteri

„ Clarkii

Salpingosca Clarkii
Salpingoeca convallaria
„ cornuta

curvipes
cylindrica ..
fusiformis . .
gracilis
infusionum . .

225
40
39i
392
223
223
664
665
666
665
664
666
665
666
285
286
285

220
224
224
412
481
806
806

343
347
343
349
259

357
348

357
350
355
348
346
35'
356

Salpingoeca inquillata ..

„ longipes .. ..

„ marina

„ mi nut a

„ napiformis ..

,, oblonga

„ petiolata

„ pyxidium ..

„ ringens .. ..

„ Steinii

„ teres

„ tintinnabulum ..

„ tuba

„ urceolata ..

„ Wallichi .. ..

Salpingcecidae

Salpistes

„ castaneus

Scaphidiodon

„ navicula ..

Sctyzopus norvegicus ..

Schizosiphon

„ socialis ..

Scyphidia

„ Fromentellii ..
„ inclinans
Styphidia inclinans
Scyphidia limacina
„ physarum

„ rugosa

Scytomonas

„ pusilla

Sisyridion cochliostoma

Solenophrya

„ crassa

Sparotricha vexillifer

Sphaerophrya

„ hydrostatica . .

„ magna .. ..

Sphcerophrya paramtzciorum
Sphaerophrya pusilla

„ sol

„ stentorea ..

„ stylonychiae . .

„ urostylae ..

Sphenomonas

„ octocostata ..

„ quadrangularis

Spirillum

Spirochona

„ gemmipara ..
„ Scheutenii ..

„ tintinnabulum . .

Spiromonas

„ angustata ..

„ distorta

„ volubilis

Spirostomidae

Spirostomum

„ ambiguum

„ teres

Spirostomum filu m
„ virens
„ virescens ..
Spongasteriscus

354
353
352
347
355
358
349
347
354
346
353
354
35i
353
348
342
590

595
750
750
800
778
778
658
659
659
667
658
658
659
241
241
501
828
828
86 1
808
Sn
808
810
808
810
810
810
809
438
439
439
244
660
660
66 1
66 1
297
298
298
298

583
586
586
586
587
587
587
229

9io

INDEX.

Spongasteriscus quadricornis
„ tetraceras . .

Sponges, Nature and Affinities

Spongida

Spongocyclia

„ charybdaea

„ cycloides ..

„ elliptica ..

,, orthogona

„ scyllaea

Spongomonadidae

Spongomonas

„ discus

„ intestinalis

„ sacculus ..

„ uvella

Spontaneous Generation

Spumella

„ guttula

Spumella neglecta

„ termo

Spumella vivipara

Spumella vulgar is

Spumellidas

Squamulina scopula

Steinia ferruginea

„ platystoma

Stentor .. .-.

Stentor albus

Stentor amethystinus ..

Stentor anceps

Stentor auricula

„ Barretti

Stentor cuculhts

Stentor caeruleus

Stentor deformis

„ elegans

,, fimbriattis

„ fuscus

Stentor igneus

Stentor Mutter i

Stentor multiformis

Stentor nanus

Stentor niger

„ pediculatus

„ polymorphus ..

Stentor pygmaus

Stentor Rceselii

Stentor roseus

Stentoridas

Stephanomonadidae

Stephanomonas

„ locellus

Sterromonas

„ Biitschlii ..

„ formicina ..

Stichochaeta

Stichoch&ta cornuta

„ pediculiformis ..

Stichotricha

„ aculeata

„ cornuta .. ..

marina

229

229

143-194

- 365
.. 228

229

.. 229
.. 229
.. 229

229

.. 284
.. 286
.. 287
.. 287
.. 288
.. 288
118-142
•• 305
•• 3°5
•• 305
•• 305
.. 306

•• 305

•• 305

160

- 787
.. 787

remex . .
sccunda

596
86 1
596
595
593
596

593
596
596
596
596

594
590

59I
596

594
596
590
407

59i
596
588
465
466
466
420
421
420

775
776
775
775
777
776
778
777
776

Stichotricha socialis

Strombidinopsis

„ gyrans.. ,

Strombidium

„ acuminatum ,

„ Biitschlii ..

„ caudatum

„ Claparedi

„ globosum

Strombidium polymorphum
Strombidium sulcatum ..
„ turbo

„ urceolare

„ viride

Strongylidium

„ crassum

Stylobryon

„ epistyloides
Stylobryon insignis
Stylobryon petiolatum ..

Stylochona

„ coronata
„ nebalina

Stylochrysalis

„ parasita ..

Stylocola

„ ampulla

„ striata

Stylonethes

„ tardus

Stylonychia

Stylonychia appendiculatus

,, echinata
Stylonychia fissiseta
Stylonychia histrio

„ lanceolata ..
Stylonychia macrostyla
„ mytilus
„ pustulata ..

Styloplotes

„ appendiculatus .
Sub-kingdom Protozoa ..
Sycandra raphanus

Sycon ciliatum

Syncrypta

„ volvox

Synura

„ uvella

Telotrochidium

„ crateriforme

Tentaculifera

„ -Actinaria

„ -Suctoria..

Tetramitidae

Tetramitus

„ descissus
,, rostratus
„ sulcatus

Tetraselmis

„ cordiformis

Thuricola

„ folliculata
„ operculata
valvata .

778
613
614
633
634
634
635
634
635
582
633
634
634
635
779
779
278
279
278
278
662
663
662

405
405
730
730
730
782
782
790
800
783
79i
789
783
791

790

.. 800
.. 800
-.31-48
180, 181

•• 173

•• 413

•• 413

.. 411

.. 412

478, 643
.. 643
40, 80 1
.. 846
.. 806
.. 312
•• 313

313
3H
315
315
718
718
719
718

INL

PAGE

^EX.

Trachelomonas aspera ..
Trachelomonas bulla ..
, caudata ..
, cylindrica ..
, eurystoma

Oil

PAGE

.. - 391
- .. 391
- .. 390

.. -. 39°

514.

Tintinnidium .. .. . . .

.. .. 611

„ fluviatile ..
„ marinum ..
„ semiciliatum ..
Tintinnodae

.. .. 611
.. .. 611
.. 612

601

, lagenella
Trachelomonas nigricans
Trachelomonas rugulosa
„ volvocina

.. .. 389

" ". 389
389

Tintinnopsis ..

617

„ beroidea ..
Tintinnus

.. .. 617

„ acuminatus ..
„ amphora
Tintinnus ampulla
Tintinnus annulatus
„ campanula ..

.. .. 606
.. .'. 606
.. 610,627
609
617,609
616 608

Trachelophyllum

5O2

„ apiculatum
„ pusillum ..
Tremella pruniformis ..
Trepomonadidae

.. 502
.. .. 503
.. .. 736

„ cothurnia
„ denticulatus .. *..
„ Ehrenbergii ..
Tintinnus fluviatilis

.. .. 608
607
.. 607
.. .. 611
. .. 608

„ agilis .. ..

.. 248, 300

536

„ ambigua .

,, inquilinus

604
. .. 608

• •• 536

„ mediterraneus
„ mucicola
„ obliquus .. '• ..
„ quadrilineatus
Tintinnus spiralis ..

.. 610
.. 605
. .. 606
607
610,627
. .. 606

.. 536

536

Trichoda char on

.. 800

Trichoda cimex .. .. • ..

800

Jixa
foeta

.. .. 8l3

767

„ subulatus

„ urnula

600

grandinella
index

. .. 632

„ ventricosus ..
Torquatella

.. 609
.. .. 621

inquilinus
nasamomum .
navicula

.. 603

• •• 751

„ typica
Torquatellidae

.. .. 621
.. .. 621

, pellionella
Trichoda pirum

.. .. 786

Trachelius anas .. ..' ..
„ apiculatum ..
„ dendrophilus
,, falx
„ globulifer ..
„ lamella
„ meleagris
Trachelius ovum
Trachelius pusillus
,, striatus
„ stricta
„ teres
„ trichophora
Trachelocerca

.. .. 502

.. .. ' 527
.. .. 431

'.'. " 526

.. .. 522
.. .. 503
.. .. 522
.. .. 529
.. .. 521
. 376, 523

C 14.

Trichoda piscis .. .

.. 780

Trichoda pura

Trichoda transfuga

7Q7

„ versatilis

Trichodina

f)A C

„ baltica
„ digitodiscus ..
Trichodina grandinella 4^,
Trichodina pediculus
„ scorpasna ..
„ Steinii

.. .. 649
.. .. 649

.'.' '.'. 646
.. .. 649
648

Trichodina tentaculata ..
„ volvox

.. 640

6^2

Trachelocerca biceps
„ linguifera
Trachelocerca olor ..

. .. 515
. .. 515

„ itorax

7J.6

Trichodinopsis

614

„ phcenicopterus
Trachelocerca sagitta

. .. 5I6

„ paradoxa
Trichogaster

614

764.

Trachelocerca tenuicollis
„ versatilis
Trachelocerca -viridis ..
Trachelocercidas

• •• 517

• •• 515
c 14.

„ pilosus
Trichomonas

.. .. 764

.. 308

„ batrachorum . .
Trichomonas hirsuta . . . .

.. .. 308

.. 466

. .. 388

„ acuminata ..
Trachelomonas areolata
Trachelomonas armata

. .. 391
. .. 391

. .. 39°

Trichomonas locelhts
„ minima .,
Trichomonas vaginalis ..

. .. 466
. .. 466
. .. 309

912

INDEX.

Trichonema 469

„ hirsuta

Trichonemidae
Trichonympha

agilis
Trichonymphidae ..

Trichophrya 811

„ digitata ..

„ epistylidis ..

Trichophrya Ophrydii ..

Trichopus

„ dysteria

Trimastigidae 307

Trimastix

„ marinus

Trochilia 756

„ marina ..
„ palustris ..
„ polonica ..
„ sigmoides
Tropidocyathus octocostatus
Tropidocyphus

Trypanosoma 218

„ Eberthi ,

„ sanguinis

Trypanosomata

Undulina ranarum

Urceolaria 649

„ mitra

Urceolariidae 645

Urceolus Alenizini ..

Urnula 807

„ epistylidis ..

Urocentrum 641

„ turbo
Uroglena 414

„ volvox
Uroleptus 779

„ agilis .

„ gibbus .

„ mobilis .

„ musculus

„ piscis

Urostyia 764

„ flavicans ..
„ grandis . .
„ viridis
„ Weissii ..
Urotricha

„ farcta
„ lagenula

Uvella 406

Uvella chamtzmorus
„ disjuncta

„ uva 267

„ virescens

Vaginicola 714

PAGE

PAGE

469

Vaginicola attenuata

717

469

„ crystallina . .

715

468

Vaginicola decumbens ..

731

552

-Vaginicola gigantea

716

552

, globosa

716

551

, grandis

716

811

, inclinata

717

812

, ingenita

717

811

, tincta ..

716

813

Vaginicola valvata

718

758

Vaginicola vestita ..

717

758

Vaginicolina

714.

/ J

^07

on

•J /

312

„ ciliata

613

~M2

Vibrio

•2 A A

o ^
756

CIC

/ J

7">7

olor

C 1C

/ J /

757

„ pro feus

515

757

„ verminus ..

.. .. 548, 550

757

Volvox vegetans

267

43Q

Vorticella

667

*rJ.7
438

„ alba

676

218

Vorticella ampulla

598

219

„ anastatica

.. ;. .. 701

219

„ annular is

689

218

Vorticella aperta ..

680

„ appuncta

688

219

Vorticella berberina

712

649

Vorticella brevistyla

675

650

„ campanula ..

678

645

„ chlorostigma

686

857

, citrina ..

678

807

, communis

681

807

, constricta

682

641

, convallaria . .

686

641

, crassicaulis ..

.. /. .. 676

414

, cratera ..

679

414

Vorticella crateriformis

.. .. .. 644

779

Vorticella cucullus ..

677

78i

Vorticella cyathina

689

780

Vorticella dilatata ..

681

78i

„ dubia .. ..

676

779

„ elongata

686

780

„ fasciculata

.. .; .. 681

780

„ fluvialis ..

676

78i

Vorticella folliculata

719

546

„ gemella ..

680

546

Vorticella globularia

681

797

„ gracilis .. ..

675

797

„ hamata ..

678

764

Vorticella hians

690

766

„ inclinans

•• •• 557,659

765

„ infusionum . .

684

765

Vorticella longifilum

677

764

„ mamillata

682

504

„ margaritifera

682

505

Vorticella margaritata ..

.. .. .. 688

5°5

Vorticella marina ..

.. .. .. 685

406

„ microscopica

688

267

„ microstoma ..

' 683

34i

„ monilata

688

267

Vorticella multangula .".

686

412

„ multiformis ..

595

„ nasuta ..

639

7H

Vorticella nebulifera

673

INDEX.

913

PAGE

Vorticella nutans .. .. 679

Zoothamnium affine

PAGE

.. .. 698

„ patellina

679

„ alternans

.. .. 695

„ picta .. ..

675

„ arbuscula

.. .. 694

Vorticella polymorphus

59i

„ aselli

.. .. 698

„ polypina

691

carcini

. . 700

Vorticella procumbens ..

680

Cienkowskii . .

.. .. 696

„ putrinum

684

dichotomum ..

.. .. 697

Vorticella Pyriformis ..

659

elegans ..

.. .. 699

„ pyrum .. ..

685

gleniscum

.. .. 697

Vorticella quadrangularis

685

macrostylum ..

.. .. 699

Vorticella ringens ..

659

marinum

.. 700

Vorticella spectabilis

687

niveum

.. .. 694

„ sphasrica

681 •

nutans

.. .. 698

„ striata ..

684

parasita ..

.. .. 698

„ telescopica . .

677

pictum ..

.. .. 699

Vorticella vaginata

605

Zoothamnium plumosum

.. .. 695

„ -versatilis

736

Zoothamnium simplex ..

700

Vorticellidae 654

Zoothamnium spirals ..

.. .. 695

Vorticellina 657

vyy

4.17

Wagner ella cylindroconica 639

„ inaequalis

.. .. 417

„ nebulosa

.. .. 417

2 G

LONDON :

PRINTED BY WILLIAM CLOWES AND SONS, LIMITED,
STAMFORD STREET AND CHARING CROSS.