subfamily are often found in close proximity to one another and to
zoaria of _Fredericella_, and that the branches of the different species
are sometimes entangled together in such a way that they appear, unless
carefully separated, to belong to the same zoarium.
Genus 1. PLUMATELLA, _Lamarck_.
_Plumatella_, Lamarck, Animaux sans Vert. (ed. 1re) ii, p.
106 (1816).
_Alcyonella_, _id_., _ibid_. p. 100.
_Plumatella_, Allman, Mon. Fresh-Water Polyzoa, p. 92
(1857).
_Alcyonella_, _id_., _ibid_. p. 86.
_Plumatella_, Hyatt, Comm. Essex Inst. iv, p. 207, pl. viii
(1866).
_Plumatella_, Jullien (_partim_), Bull. Soc. zool. France,
x, p. 100 (1885).
_Hyalinella_, _id_., _ibid_. p. 133.
_Plumatella_, Kraepelin, Deutsch. Süsswass. Bryozoen, i, p.
104 (1887).
_Plumatella_, Braem, Unter. ü. Bryozoen des süssen Wassers,
p. 2 (Bibliotheca Zoologica, ii, 1890).
_Zoarium_ dendritic, recumbent, erect, or partly recumbent and partly
erect.
_Zooecia_ tubular, not confined in a gelatinous synoecium; the ectocyst
usually horny.
_Statoblasts_ often of two kinds, free and stationary, the latter
without air-cells and as a rule adherent by one surface, the former
provided with a well-developed ring of air-cells but without marginal
processes, oval in form, never more than about 0.6 mm. in length.
_Polypide_ with less than 65 tentacles.
[Illustration: Fig. 42.--Outlines of free statoblasts of _Plumatella_
(enlarged).
A, of _P. fruticosa_ (Calcutta); B, of _P. emarginata_ (Calcutta); C, of
_P. javanica_ (Travancore); D, of _P. diffusa_ (Sikhim); E, of _P.
allmani_ (Bhim Tal); F, of _P. diffusa_ (Rajshahi, Bengal); G, G', of
_P. punctata_ (Calcutta); H, of _P. diffusa_ (Sikhim), statoblast
further enlarged: A=outline of capsule; B=limit of swim-ring on
ventral surface; C=limit of swim-ring on dorsal surface. [The dark
area represents the capsule of the statoblast.]]
Certain forms of this genus are liable to become compacted together in
such a way as to constitute solid masses consisting of elongate vertical
zooecia closely parallel to one another and sometimes agglutinated by
means of a gummy substance. These forms were given by Lamarck in 1816
the name _Alcyonella_, and there has been much dispute as to whether
they represent a distinct genus, distinct species, or merely varieties
or phases of more typical forms. It appears to be the case that all
species which produce vertical branches are liable to have these
branches closely packed together and the individual zooecia of which
they are composed more or less greatly elongated. It is in this way that
the form known to Allman as _Alcyonella benedeni_ is produced from the
typical _Plumatella emarginata_. Other forms go further and secrete a
gummy substance that glues the upright zooecia together and forces them
to elongate themselves without branching. In these conditions the
zooecia become polygonal in cross-section. It is probable that such
forms (_e. g._, _Plumatella fungosa_ (Pallas)) should rank as distinct
species, for the gummy secretion is present in great profusion even in
young zoaria in which the zooecia have not yet assumed a vertical
position. No such form, however, has as yet been found in India, and in
any case it is impossible to regard _Alcyonella_ as a distinct genus.
_Key to the Indian Species of_ Plumatella.
I. Ectocyst more or less stiff, capable of
transverse wrinkling only near the tips of
the zooecia, never contractile or greatly
swollen; zooecia rounded[BF] at the tip when
the polypide is retracted. Free statoblasts
elongate; the free portion of their swim-ring
distinctly narrower at the sides than at
the ends.
A. Ectocyst by no means rigid, of a uniform
pale colour; zooecia never emarginate or
furrowed, straight, curved or sinuous,
elongate, cylindrical _fruticosa_, p. 217.
B. Ectocyst rigid; zooecia (or at any rate
some of the zooecia) emarginate and furrowed.
_b_. Ectocyst darkly pigmented over the
greater part of each zooecium, white
at the tip; branching of the zoarium
practically dichotomous, profuse, as
a rule both horizontal and vertical;
zooecia straight or slightly curved
or sinuous _emarginata_, p. 220.
_b'_. Ectocyst colourless and hyaline;
branching of the zoarium sparse,
lateral, irregular, horizontal;
zooecia nearly straight, strongly
emarginate and furrowed _javanica_, p. 221.
_b''_. The majority of the zooecia distinctly
L-shaped, one limb being as a rule
adherent; ectocyst never densely
pigmented.
beta. Zooecia cylindrical, their furrowed
keel never prominent _diffusa_, p. 223.
beta'. Zooecia (or at any rate some of the
zooecia) constricted or tapering at
the base, their emargination and
furrow conspicuous _allmani_, p. 224.
II. Ectocyst stiff; zooecia truncated when the
polypide is retracted. Surface of zooecia
minutely roughened, distinctly annulate on
the distal part _tanganyikæ_, p. 225.
III. Ectocyst swollen and contractile, capable
of transverse wrinkling all over the
zooecium; zooecia never emarginate _punctata_, p. 227.
[Footnote BF: In specimens preserved in spirit they are apt
to collapse and therefore to become somewhat concave.]
There has always been much difficulty in separating the species of
_Plumatella_, and even now there is no general consensus of opinion as
to the number that should be recognized. The difficulty, however, is
much reduced if the following precautions are observed:--
(1) If the zoarium appears to be tangled, if the branches
intertwine or overlap, or if the zooecia are closely pressed
together, the whole mass should be carefully dissected out.
This is necessary not only because zoaria belonging to
different species are sometimes found entangled together but
also because it is often difficult to recognize the
characteristic method of branching and shape of the zooecia
unless it is done.
(2) As large a part as possible of each zoarium should be
examined, preferably with a binocular microscope, and
allowance should be made for irregularities and
abnormalities of all kinds. What must be observed is the
rule rather than the exceptions.
(3) When the statoblasts are being examined, care must be
taken that they lie flat and that their surface is parallel
to that of the nose-piece of the microscope. If they are
viewed obliquely it is impossible to see their true outlines
and proportions.
(4) In order to see the relative proportions of the capsule
and the swim-ring it is necessary that the statoblast should
be rendered transparent. This is often difficult owing to
the presence of air in the air-cells, but strong nitric acid
applied judiciously will render it possible (p. 240).
In supervising the preparation of the plates that illustrate this genus
I have impressed upon the artist the importance of representing what he
saw rather than what he thought he ought to see, and the figures are
very close copies of actual specimens. I have deliberately chosen for
representation specimens of _Plumatella_ preserved by the simple methods
which are often the only ones that it is possible for a traveller to
adopt, for the great majority of naturalists will probably have no
opportunity of examining living specimens or specimens preserved by
special methods, and the main object, I take it, of this series is to
enable naturalists first to distinguish the species described and then
to learn something of their habitat and habits.
GEOGRAPHICAL DISTRIBUTION.--Of the seven species included in this key
five have been found in Europe (namely _P. fruticosa_, _P. emarginata_,
_P. diffusa_, _P. allmani_, and _P. punctata_), while of these five all
but _P. allmani_ are known to occur in N. America also. _P. javanica_ is
apparently peculiar to the Oriental Region, while _P. tanganyikæ_ has
only been taken in Central Africa and in the Bombay Presidency.
TYPES.--Very few of the type-specimens of the older species of
_Plumatella_ are in existence. Allman's are neither in Edinburgh nor in
London, and Mr. E. Leonard Gill, who has been kind enough to go through
the Hancock Collection at Newcastle-on-Tyne, tells me that he cannot
trace Hancock's. Those of the forms described by Kraepelin are in
Hamburg and that of _P. tanganyikæ_ in the British Museum, and there are
schizotypes or paratypes of this species and of _P. javanica_ in
Calcutta. The types of Leidy's species were at one time in the
collection of the Philadelphia Academy of Science.
BIOLOGY.--The zoaria of the species of _Plumatella_ are found firmly
attached to stones, bricks, logs of wood, sticks, floating seeds, the
stems and roots of water-plants, and occasionally to the shells of
molluscs such as _Vivipara_ and _Unio_. Some species shun the light, but
all are apparently confined to shallow water.
Various small oligochæte worms (e. g., _Chætogaster spongillæ_,[BG]
_Nais obtusa_, _Nais elinguis_, _Slavina appendiculata_ and _Pristina
longiseta_[BH]), take shelter amongst them; dipterous larvæ of the genus
_Chironomus_ often build their protective tubes at the base of the
zoaria, and the surface of the zooecia commonly bears a more or less
profuse growth of such protozoa as _Vorticella_ and _Epistylis_. I have
seen a worm of the genus _Chætogaster_ devouring the tentacles of a
polypide that had been accidentally injured, but as a rule the movements
of the lophophore are too quick to permit attacks of the kind, and I
know of no active enemy of the genus. The growth of sponges at the base
of the zoaria probably chokes some species, but one form (_F.
fruticosa_) is able to surmount this difficulty by elongating its
zooecia (p. 219). A small worm (_Aulophorus tonkinensis_) which is
common in ponds in Burma and the east of India as far west as Lucknow,
often builds the tube in which it lives mainly of the free statoblasts
of this genus. It apparently makes no selection in so doing but merely
gathers the commonest and lightest objects it can find, for small seeds
and minute fragments of wood as well as sponge gemmules and statoblasts
of other genera are also collected by it. I know of no better way of
obtaining a general idea as to what sponges and phylactolæmata are
present in a pond than to examine the tubes of _Aulophorus tonkinensis_.
[Footnote BG: Annandale, J. As. Soc. Bengal (n. s.) ii, p.
188, pl. i (1906).]
[Footnote BH: See Michaelsen, Mem. Ind. Mus. i, pp. 131-135
(1908).]
I am indebted to Mr. F. H. Gravely, Assistant Superintendent in the
Indian Museum, for an interesting note regarding the food of
_Plumatella_. His observations, which were made in Northamptonshire,
were unfortunately interrupted at a critical moment, but I have
reproduced them with his consent in order that other observers may
investigate the phenomena he saw. Mr. Gravely noted that a small green
flagellate which was abundant in water in which _Plumatella repens_ was
growing luxuriantly, was swallowed by the polypides, and that if the
polyparium was kept in a shallow dish of water, living flagellata of the
same species congregated in a little pile under the anus of each
polypide. His preparations show very clearly that the flagellates were
passing through the alimentary canal without apparent change, but the
method of preservation does not permit the retractile granules, which
were present in large numbers in the cell-substance of the flagellates,
to be displayed and it is possible that these granules had disappeared
from those flagellates which are present in the recta of his specimens.
It is clear, therefore, either that certain flagellates must pass
through the alimentary canal of _Plumatella_ unchanged, or that the
polyzoon must have the power of absorbing the stored food material the
flagellates contain without doing them any other injury.
The free statoblasts of _Plumatella_ are as a rule set free before the
cells they contain become differentiated, and float on the surface of
the water for some time before they germinate; but occasionally a small
polypide is formed inside the capsule while it is still in its parent
zooecium. I have, however, seen only one instance of this premature
development, in a single statoblast contained in a small zoarium of _P.
fruticosa_ found in Lower Burma in March. The fixed statoblasts usually
remain fixed to the support of the zoarium, even when their
parent-zooecium decays, and germinate _in situ_.
The larva (fig. 40 C, p. 207) that originates from the egg of
_Plumatella_ is a minute pear-shaped, bladder-like body covered
externally with fine vibratile threads (cilia) and having a pore at the
narrow end. At the period at which it is set free from the parent
zooecium it already contains a fully formed polypide or pair of
polypides with the tentacles directed towards the narrow end. After a
brief period of active life, during which it moves through the water by
means of its cilia, it settles down on its broad end, which becomes
adhesive; the polypide or pair of polypides is everted through the pore
at the narrow end, the whole of this end is turned inside out, and a
fresh polyparium is rapidly formed by budding.
29. Plumatella fruticosa, _Allman_. (Plate III, fig. 1; plate IV, fig.
4; plate V, fig. 1.)
_Plumatella fruticosa_, Allman, Ann. Nat. Hist. xiii, p. 331
(1844).
_Plumatella repens_, van Beneden (? _nec_ Linné), Mém. Acad.
Roy. Belg. 1847, p. 21, pl. i, figs. 1-4.
_Plumatella fruticosa_, Johnston, Brit. Zooph. (ed. 2), p.
404 (1847).
_Plumatella coralloides_, Allman, Rep. Brit. Assoc. 1850, p.
335.
_Plumatella stricta_, _id._, Mon. Fresh-Water Polyzoa, p.
99, fig. 14 (1857).
_Plumatella fruticosa_, _id._, _ibid._ p. 102, pl. vi, figs.
3-5.
_Plumatella coralloides_, _id._, _ibid._ p. 103, pl. vii,
figs. 1-4.
_Plumatella repens_ and _P. stricta_, Carter, Ann. Nat.
Hist. (3) iii, p. 341 (1859).
_Plumatella lucifuga_, Jullien (_partim_), Bull. Soc. zool.
France, x, p. 114 (1885).
_Plumatella princeps_ var. _fruticosa_, Kraepelin, Deutsch.
Süsswasserbryozoen, i, p. 120, pl. vii, fig. 148 (1887).
_Plumatella fruticosa_, Braem, Unter. ii. Bryozoen des
süssen Wassers, p. 9, pl. i, fig. 15 (Bibl. Zool. ii)
(1890).
_Plumatella repens_, Annandale, J. As. Soc. Bengal (new
series) iii, 1907, p. 88.
_Plumatella emarginata_, Loppens (_partim_), Ann. Biol.
lacustre, iii, p. 161 (1908).
_Plumatella fruticosa_, Annandale, Rec. Ind. Mus. v, p. 45
(1910).
_Zoarium._ The zoarium in the typical form has a loose appearance due to
the fact that the branches are far apart and the ectocyst by no means
rigid. When young the zoarium is adherent, but in well-grown polyparia
vertical branches, often an inch or more in length, are freely produced.
As a rule they have not the strength to stand upright if removed from
the water. Branching is ordinarily lateral and as a rule occurs chiefly
on one side of a main branch or trunk. In certain circumstances upright
zooecia are pressed together and reach a great length without branching,
and in this form (_P. coralloides_, Allman) daughter-zooecia are often
produced at the tip of an elongated mother-zooecium in fan-like
formation. A depauperated form (_P. stricta_, Allman), occurs in which
the vertical branches are absent or very short. In all forms internal
partitions are numerous and stout.
_Zooecia._ The zooecia are cylindrical and bear a simple keel on their
dorsal surface. They are never emarginate or furrowed. In the typical
form their diameter is more than half a millimetre, and they are always
of considerable length. The ectocyst is thin and never very rigid or
deeply pigmented, the colour usually being an almost uniform pale
pinkish brown and fading little towards the tip of the zooecium.
_Statoblasts._ Both free and stationary statoblasts are formed, but the
latter are rare and do not always adhere. They resemble the free
statoblasts in general form but have a solid margin instead of a
swim-ring and are often minutely serrated round the edge. The free
statoblasts are at least considerably, sometimes very elongate; in all
zoaria it is possible to find specimens that are more than twice as long
as broad. The capsule is relatively large and resembles the swim-ring in
outline, so that the free portion of the latter is not much narrower at
the sides than at the ends. The sides are distinctly convex and the ends
rounded; the swim-ring encroaches little on the surface of the capsule.
_Polypide._ The tentacles number between 40 and 50 and are not festooned
at the base. The stomach is slender and elongate.
TYPE not in existence.
SYSTEMATIC REMARKS.--_P. fruticosa_ is closely allied to _P. repens_
(European and N. American) but always has much longer statoblasts. Three
phases of the species may be distinguished as follows:--
A. (_Forma typica_). Zooecia stout in form, not greatly
elongate; free branches produced in profusion.
B. (_P. stricta_, Allman, _P. repens_, van Beneden). Zooecia
slender; free branches absent or consisting of two or three
zooecia only.
C. (_P. coralloides_, Allman). Vertical zooecia pressed
together and greatly elongated.
Indian specimens of the typical form agree well with German specimens
labelled by Prof. Kraepelin _P. princeps_ var. _fruticosa_, and
specimens of the _coralloides_ phase could hardly be distinguished from
similar specimens from Scotland.
GEOGRAPHICAL DISTRIBUTION.--_P. fruticosa_ is widely distributed in
Europe and probably in N. America. I have seen Indian specimens from the
Punjab (Lahore, _Stephenson_), from Bombay, from Travancore, from
Calcutta and other places in the Ganges delta, from Rajshahi (Rampur
Bhoolia) on the R. Ganges, from Kurseong in the E. Himalayas (alt. 4,500
feet), and from Kawkareik in Tenasserim. Statoblasts found on the
surface of a pond near Simla in the W. Himalayas (alt. _ca._ 8,000
feet), probably belong to this species.
BIOLOGY.--Allman states that in England _P. fruticosa_ is fond of still
and slowly-running water. The typical form and the _coralloides_ phase
grow abundantly in the Calcutta tanks, the former often attaining an
extraordinary luxuriance. I have found the var. _stricta_ only in water
in which there was reason to suspect a lack of minute life (and
therefore of food), viz. in Shasthancottah Lake in Travancore, in a
swamp in Lower Burma, and in a small jungle stream near the base of the
Western Ghats in Travancore. The species is the only one that I have
seen in running water in India, and the specimens obtained in the jungle
stream in Travancore are the only specimens I have taken in these
circumstances. _P. fruticosa_ always grows near the surface or near the
edge of water; it is found attached to the stems of bulrushes and other
aquatic plants, to floating seeds and logs and (rarely) to stones and
bricks. So far as my experience goes it is only found, at any rate in
Calcutta, in the cold weather and does not make its appearance earlier
than October.
The form Allman called _P. coralloides_ was found by him, "attached to
floating logs of wood, together with _P. repens_ and _Cordylophora
lacustris_, and generally immersed in masses of _Spongilla
fluviatilis_." I have always found it immersed in sponges (_S.
lacustris_, _S. alba_, _S. carteri_, and _S. crassissima_), except when
the sponge in which it had been immersed had decayed. Indeed, the
peculiar form it has assumed appears to be directly due to the pressure
of the growing sponge exerted on the zooecia, for it is often possible
to find a zoarium that has been partially overgrown by a sponge and has
retained its typical form so long as it was free but has assumed the
_coralloides_ form where immersed.[BI] In Shasthancottah Lake,
Travancore, I found specimens of the _stricta_ phase embedded in the
gelatinous mass formed by a social rotifer and to some extent
assimilated to the _coralloides_ form.
[Footnote BI: Braem (_op. cit._, p. 3, pl. i, fig. 1), has
described and figured under the name _P. fungosa_ var.
_coralloides_, Allman, a dense form that somewhat resembles
this phase of _P. fruticosa_ but has become compacted
without external pressure. It is, however, probably a form
of _P. repens_ rather than _P. fungosa_ and differs in its
broad statoblasts from any form of _P. fruticosa_. I have
examined specimens of the same form from England.]
30. Plumatella emarginata, _Allman_. (Plate III, fig. 2; plate IV, figs.
1, 1 _a._)
_Plumatella emarginata_, Allman, Ann. Nat. Hist. xiii, p.
330 (1844).
_Plumatella emarginata_, Johnston, Brit. Zooph. (ed. 2), p.
404 (1847).
_Alcyonella benedeni_, Allman, Mon. Fresh-Water Polyzoa, p.
89, pl. iv, figs. 5-11 (1857).
_Plumatella emarginata_, _id._, _ibid._ p. 104, pl. vii,
figs. 5-10.
_Plumatella lucifuga_, Jullien, Bull. Soc. zool. France, x,
figs. 89, 90, p. 114 (1885).
_Plumatella princeps_ var. _emarginata_, Kraepelin
(_partim_), Deutsch. Süsswasserbryoz. p. 120, pl. iv, fig.
108, pl. v, fig. 123 (1887).
_Plumatella emarginata_, Braem, Unter. ii. Bryoz. süssen
Wassers, p. 9, pl. i, figs. 12, 14 (Bibl. Zool. ii) (1890).
_Plumatella emarginata_, Annandale (_partim_), J. As. Soc.
Bengal, (new series) iii, 1907, p. 89.
_Plumatella princeps_, Loppens (_partim_), Ann. Biol.
lacustre, iii, p. 162, fig. 7 (1908).
_Plumatella emarginata_, Annandale, Rec. Ind. Mus. v, p. 47
(1910).
_Zoarium._ The zoarium often covers a considerable area on flat surfaces
and is sometimes entirely recumbent. More usually, however, the younger
part is vertical. In either case the branching is practically
dichotomous, two young zooecia arising almost simultaneously at the tip
of a mother-zooecium and diverging from one another at a small angle.
When the zoarium becomes vertical, rigid branches of as much as an inch
in length are sometimes produced in this way and, arising parallel to
one another, are pressed together to form an almost solid mass
(=_Alcyonella benedeni_, Allman). In such cases the basal zooecium or at
any rate the basal part of each upright branch is considerably
elongated. In recumbent zooecia the main branches often radiate outwards
from a common centre.
_Zooecia._ The zooecia are of almost equal width throughout, slender,
and moderately elongate when recumbent. Their ectocyst is stiff; they
are emarginate at the tip and more or less distinctly furrowed on the
dorsal surface, the keel in which the furrow runs not being prominent.
The orifice is often on the dorsal surface even in upright branches.
Each zooecium is of a dark brown or almost black colour for the greater
part of its length but has a conspicuous white tip which is extended
down the dorsal surface in the form of a triangle, its limits being
rather more extensive than and parallel to those of the emargination.
_Statoblast._ The majority of the free statoblasts are elongate and
truncate or subtruncate at the extremities, the sides being as a rule
straight and parallel. In every polyparium specimens will be found that
are between twice and thrice as long as broad. The capsule is, however,
relatively much broader than the swim-ring, often being nearly circular,
and there is therefore at either end a considerable extent of free
air-cells, while the extent of these cells at the sides of the capsule
is small. The air-cells cover a considerable part of the dorsal surface
of the capsule. Fixed statoblasts are usually found in old colonies,
especially at the approach of the hot weather. They have an oval form
and are surrounded by a membranous margin on which traces of
reticulation can often be detected. As a rule statoblasts of both types
are produced in considerable but not in excessive numbers.
_Polypide._ There are about 40 tentacles, the velum at the base of which
extends upwards for a considerable distance without being festooned. The
stomach is elongate and slender and narrowly rounded at the base.
The method of branching, the coloration of the zooecia and the form of
the free statoblast are all characteristic. Luxuriant or closely
compressed zoaria of _P. diffusa_ often bear a superficial resemblance
to those of _P. emarginata_, but the resemblance disappears if they are
carefully dissected out. Indian specimens of _P. emarginata_ agree
closely with European ones.
GEOGRAPHICAL DISTRIBUTION.--_P. emarginata_ is a common species in
Europe, N. America, and southern Asia and probably also occurs in Africa
and Australia. I have examined specimens from Calcutta, Rangoon, and
Mandalay in Indian territory, and also from Jalor in the Patani States
(Malay Peninsula) and the Talé Noi, Lakon Sitamarat, Lower Siam.
Gemmules found by Apstein (Zool. Jahrb. (Syst.) xxv, 1907, p. 201) in
plankton from the Colombo lake may belong to this species or to any of
the others included by Kraepelin in his _P. princeps_.
BIOLOGY.--In Ireland Allan found _P. emarginata_ in streams and
rivulets, but it also occurs in European lakes. In India I have only
found it in ponds. It prefers to adhere to the surface of stones or
bricks, but when these are not available is found on the stems of
water-plants. In the latter position the form called _Alcyonella
benedeni_ by Allman is usually produced, owing to the fact that the
upright branches are crowded together through lack of space, very much
in the same way (although owing to a different cause) as those of _P.
fruticosa_ are crowded together in the _coralloides_ phase, to which the
_benedeni_ phase of _P. emarginata_ is in many respects analogous.
Although it is essentially a cold-weather species in Calcutta, _P.
emarginata_ is sometimes found in a living condition during the "rains."
Zoaria examined at this season, however, contains few living polypides,
the majority of the zooecia having rotted away and left fixed
statoblasts only to mark their former position.
31. Plumatella javanica, _Kraepelin_.
_Plumatella javanica_, Kraepelin, Mitt. Nat. Mus. Hamb.
xxiii, p. 143, figs. 1-3 (1903).
_Plumatella emarginata_ var. _javanica_, Loppens, Ann. Biol.
lacustre, iii, p. 162 (1908).
_Plumatella javanica_, Annandale, Rec. Ind. Mus. v, p. 50
(1910).
_Plumatella allmani_ var. _dumortieri_, _id._ (_partim_)
(_nec_ Allman), _ibid._ p. 49.
This species is related to _P. emarginata_, from which it may be
distinguished by the following characters:--
_Zoarium._ The zoarium is always entirely recumbent and branches
sparingly; its method of branching does not approach the dichotomous
type but is lateral and irregular. Linear series of zooecia without
lateral branches are often formed.
_Zooecia._ The zooecia are slender and often very long; they are
strongly emarginate and furrowed, and the keel that contains the furrow
is conspicuous. The ectocyst is hyaline and as a rule absolutely
colourless.
_Statoblasts._ The free statoblasts are variable in length, sometimes
distinctly elongate, sometimes elongate only to a moderate degree; they
are rounded at the extremities and have the sides slightly or distinctly
convex outwards. The capsule is relatively large, and the free portion
of the swim-ring is not much broader at the ends than at the sides. The
fixed statoblasts are elongate and surrounded by an irregularly shaped
chitinous membrane, which is often of considerable extent. The whole of
the dorsal surface is covered with what appear to be rudimentary
air-spaces some of which even contain air.
The transparent glassy ectocyst and strong furrowed keel of this species
are very characteristic, but the former character is apt to be obscured
by staining due to external causes, especially when the zoarium is
attached to dead wood. The shape of the free statoblasts is too variable
to be regarded as a good diagnostic character, but the fixed
statoblasts, when they are to be found, are very characteristic in
appearance. _P. javanica_ appears to be closely related to Allman's _P.
dumortieri_, with which stained zoaria are apt to be confused. The
character of the ectocyst is, however, different, and the free part of
the swim-ring is distinctly narrower at the sides of the free
statoblasts. Dr. Kraepelin has been kind enough to send me one of the
types.
TYPES in the Hamburg and Indian Museums.
GEOGRAPHICAL DISTRIBUTION.--Java, Penang, India. Indian localities
are:--BENGAL, Calcutta; Berhampore, Murshidabad; R. Jharai, Siripur,
Saran district, Tirhut: E. HIMALAYAS, Kurseong, Darjiling district (alt.
4,500 feet): MADRAS PRESIDENCY, canal near Srayikaad, Travancore. Mr. C.
W. Beebe has recently sent me a specimen taken by him in the Botanical
Gardens at Penang.
BIOLOGY.--Very little is known about the biology of this species.
Kraepelin took it in Java on the leaves of water-lilies. It is not
uncommon during the cold weather in the Calcutta Zoological Gardens on
floating seeds and sticks and on the stems of bulrushes; in Travancore I
took it in November on the submerged leaves of _Pandani_ growing at the
edge of a canal of slightly brackish water. Mr. Hodgart, the collector
of the Indian Museum, found it in the R. Jharai on the stems of
water-plants at a time of flood in the "rains." In Calcutta it is often
found entangled with _P. fruticosa_ and _P. emarginata_.
32. Plumatella diffusa, _Leidy_. (Plate IV, fig. 2.)
_Plumatella diffusa_, Leidy, P. Ac. Philad. v, p. 261
(1852).
_Plumatella diffusa_, Allman, Mon. Fresh-Water Polyzoa, p.
105 (1857).
_Plumatella diffusa_, Hyatt, Comm. Essex Inst. iv, pl. viii,
figs. 11, 12 (1866).
_Plumatella diffusa_, _id._, _ibid._ v, p. 107, fig. 12
(1868).
_Plumatella repens_, Jullien, Bull. Soc. zool. France, x,
fig. 37 (_lapsus_ for 73), p. 110 (1885).
_Plumatella diffusa_, _id._, _ibid._ figs. 155, 157, pp.
130, 131.
_Plumatella allmani_ var. _diffusa_, Annandale, Rec. Ind.
Mus. v, p. 49 (1910).
_Zoarium._ The zoarium often covers a considerable area on flat surfaces
and is sometimes found crowded together on the stems of plants. In the
latter case the arrangement of the main branches is distinctly radiate.
Upright branches occur rarely and never consist of more than three
zooecia. The characteristic method of branching is best represented by
the following diagram:--
[Illustration: Fig. 43.]
The partitions are stout and numerous.
_Zooecia._ The great majority of the zooecia in each zoarium are
distinctly L-shaped, the long limb being usually adherent. The vital
organs of the polypide are contained in the vertical limb, while the
horizontal one, in mature polyparia, is packed full of free statoblasts.
The zooecia are cylindrical and as a rule obscurely emarginate and
furrowed. The ectocyst is stiff; it is never deeply pigmented but is
usually of a transparent horn-colour at the base of each zooecium and
colourless at the tip, the contrast between the two portions never being
very strong. The basal portion is rough on the surface, the distal
portion smooth.
_Statoblasts._ Free statoblasts are produced in very great profusion and
fixed statoblasts are also to be found as a rule. The latter resemble
those of _P. emarginata_. The free statoblasts are never very large or
relatively broad, but they vary considerably as regards size and
outline. The capsule is large, the sides convex outwards and the
extremity more or less broadly rounded. The air-cells are unusually
large and extend over a great part of the dorsal surface of the
statoblast.
_Polypide._ The polypide is shorter and stouter than that of _P.
emarginata_ and as a rule has fewer tentacles.
The most characteristic feature of this species is the form of the
zooecia, which differ greatly from those of any other Indian species but
_P. allmani_. In the latter they are distinctly "keg-shaped" (_i. e._,
constricted at the base and swollen in the middle), and the zoarium
never spreads out over large surfaces in the way in which that of _P.
diffusa_ does.
TYPE--? in the Philadelphia Academy of Sciences.
GEOGRAPHICAL DISTRIBUTION.--This species was originally described from
North America (in which it is apparently common) and occurs also in
Europe. I have seen Indian specimens from the following
localities:--BENGAL, Calcutta and neighbourhood; Rajshahi (Rampur
Bhulia): E. HIMALAYAS, Gangtok, Native Sikhim (alt. 6,150 feet)
(_Kirkpatrick_, _Stewart_): PUNJAB, Lahore (_Stephenson_).
BIOLOGY.--_P. diffusa_ in Lower Bengal is a cold-weather species. It is
remarkable for the enormous number of gemmules it produces and is
usually found either on floating objects such as the stems of certain
water-plants, or on stones or bricks at the edge of ponds.
33. Plumatella allmani, _Hancock_. (Plate IV, figs. 3, 3 _a_.)
_Plumatella allmani_, Hancock, Ann. Nat. Hist. (2) v, p.
200, pl. v, fig. 3-4, pl. iii, fig. 2-3 (1850).
_Plumatella allmani_, Allman, Mon. Fresh-Water Polyzoa, p.
106, fig. 16 (1857).
_Plumatella elegans_, _id._, _ibid._ p. 107, pl. viii, figs.
6-10.
_Plumatella lucifuga_ ("forme rampante") Jullien, Bull. Soc.
zool. France, x, p. 114 (1885).
This species is closely allied to _P. diffusa_, from which it differs in
the following characters:--
(1) The zoarium never covers a large area and as a rule
grows sparingly and mainly in two directions.
(2) The zooecia are more irregular in shape, not so
distinctly elbowed, smaller; they have a much more
prominently keeled ridge. The great majority of them are
constricted at the base and taper towards the orifice. In
young zoaria they are almost colourless but in older ones
there is a band of not very dense pigment round the base of
the vertical limb.
(3) The free statoblasts are comparatively large and usually
show a tendency to taper at the extremities, often being
almost rhomboidal in form. The swim-ring does not extend so
far over the dorsal surface as it does in those of _P.
diffusa_; the "cells" of which it is composed are small.
TYPE not in existence.
I have seen every gradation between this form and Allman's _P. elegans_.
GEOGRAPHICAL DISTRIBUTION.--_P. allmani_ is apparently a rare species to
which there are few references in literature. It was originally
described from England and is stated by Jullien to occur in France. I
have found specimens only in the lake Bhim Tal (alt. 4,500 feet) in the
W. Himalayas.
BIOLOGY.--The original specimens were found by Hancock on stones. My own
were growing on the leaves of water-plants, usually on the under side.
When the zooecia were forced to stretch across from one leaflet to
another they assumed the sinuous form characteristic of Allman's _P.
elegans_.
34. Plumatella tanganyikæ, _Rousselet_.
_Plumatella tanganyikæ_, Rousselet, Proc. Zool. Soc. London,
1907 (i), p. 252, pl. xiv, figs. 1-4.
_Plumatella bombayensis_, Annandale, Rec. Ind. Mus. ii, p.
169, figs. 1, 2 (1908).
_Plumatella bombayensis_, _id._, _ibid._ v, p. 51 (1910).
_Zoarium._ The whole colony is recumbent but branches freely and at
short intervals in a horizontal plane, so that the zooecia become
crowded together and the branches sometimes overlap one another. The
zoarium often covers a considerable area, but growth seems to be mainly
in two directions. When growing on the stems of water-plants the
branches are often parallel and closely pressed together but remain
recumbent in this position. A stout membrane sometimes extends between
branches and individual zooecia.
_Zooecia._ The walls of the zooecia are thick, stiff, and more or less
darkly but not opaquely pigmented; the external surface, although not
very smooth, is always clean. The two most noteworthy characters of the
zooecia are (i) their truncated appearance when the polypide is
retracted, and (ii) the conspicuous, although often irregular external
annulation of their walls. The tip of each zooecium, owing to the fact
that the invaginated part of the ectocyst is soft and sharply separated
from the stiffened wall of the tube, terminates abruptly and is not
rounded off gradually as is the case in most species of the genus;
sometimes it expands into a trumpet-like mouth. The annulation of the
external surface is due to numerous thickened areas of the ectocyst
which take the form of slender rings surrounding the zooecium; they are
most conspicuous on its distal half. On the dorsal surface of the base
of each zooecium there is a conspicuous furrowed keel, which, however,
does not usually extend to the distal end; the latter is oval in
cross-section. The zooecia are short and broad; their base is always
recumbent, and, when the zoarium is attached to a stone or shell, often
seems to be actually embedded in the support; the distal part turns
upwards and is free, so that the aperture is terminal; the zooecia of
the older parts of the zoarium exhibit the specific characters much more
clearly than those at the growing points.
_Polypide._ The lophophore bears 20 to 30 tentacles, which are long and
slender; the velum at their base extends up each tentacle in the form of
a sharply pointed projection, but these projections do not extend for
more than one-fifth of the length of the tentacles. Both the velum and
the tentacular sheath bear numerous minute tubercles on the external
surface. The base of the stomach is rounded, and the whole of the
alimentary canal has a stout appearance.
[Illustration: Fig. 44.--_Plumatella tanganyikæ_ from Igatpuri Lake.
A=outline of part of zoarium from a stone, × 16; B=outline of the tip of
a single zooecium, × 70; C=free statoblast, × 70.]
_Statoblasts._ Both fixed and free statoblasts are produced, but not in
very large numbers. The latter are broadly oval and are surrounded by a
stout chitinous ring, which often possesses irregular membranous
projections; the surface is smooth. The free statoblasts are small and
moderately elongate, the maximum breadth as a rule measuring about 2/3
of the length; the capsule is relatively large and the ring of air-cells
is not very much broader at the ends than at the sides; the dorsal
surface of the central capsule is profusely tuberculate. The outline of
the whole structure is often somewhat irregular.
In deference to Mr. Rousselet's opinion expressed in a letter I have
hitherto regarded the Bombay form of this species as distinct from the
African one, and there certainly is a great difference in the appearance
of specimens taken on the lower surface of stones in Igatpuri Lake and
of the types of _P. tanganyikæ_, one of which is now in the collection
of the Indian Museum. The dark colour of the former, however, and their
vigorous growth appear to be directly due to environment, for these
characters disappear to a large extent in specimens growing on the stems
of water-plants in the same lake. Indeed, such specimens are exactly
intermediate between the form "_bombayensis_" and the typical form of
the species. _P. tanganyikæ_ is closely allied to _P. philippinensis_,
Kraepelin, from the island of Luzon, but the latter has a smooth and
polished ectocyst devoid of annulations, and zooecia of a more elongate
and regular form.
TYPES of the species in the British and Indian Museums, those of _P.
bombayensis_ in the latter collection.
GEOGRAPHICAL DISTRIBUTION.--_P. tanganyikæ_ is only known as yet from L.
Tanganyika in Central Africa and from Igatpuri in the Bombay Presidency.
BIOLOGY.--In both localities the zoaria were found in shallow water. In
L. Tanganyika they were encrusting stones and shells, while at Igatpuri
they were fixed for the most part to the lower surface of stones but
were also found on the stems of water-plants. My specimens from the
Bombay Presidency were taken, on two separate occasions, at the end of
November. At that date the zoaria were already decaying and large
blanks, marked out by fixed statoblasts, were often observed on the
stones. Probably, therefore, the species flourishes during the "rains."
35. Plumatella punctata, _Hancock_. (Plate IV, fig. 5.)
_Plumatella punctata_, Hancock, Ann. Nat. Hist. (2) v, p. 200, pl. iii,
fig. 1, and pl. v, figs. 6, 7 (1850).
_Plumatella vesicularis_, Leidy, P. Ac. Philad. vii, p. 192 (1854).
_Plumatella vitrea_, Hyatt, Comm. Essex Inst. iv, pl. ix, figs. 1, 2
(1866).
_Plumatella punctata_, Allman, Mon. Fresh-Water Polyzoa, p. 100,
fig. 15 (1857).
_Plumatella vesicularis_, _id._, _ibid._ p. 101.
_Plumatella vitrea_, Hyatt, Proc. Essex Inst. v, p. 225,
figs. 18, 19 (1868).
_Plumatella vesicularis_, _id._, _ibid._ p. 225.
_Hyalinella vesicularis_, Jullien, Bull. Soc. zool. France,
x, p. 133, figs. 165-172 (1885).
_Hyalinella vitrea_, _id._, _ibid._ p. 134, figs. 173-179.
_Plumatella punctata_, Kraepelin, Deutsch.
Süsswasserbryozoen, i, p. 126, pl. iv, figs. 115, 116; pl.
v, figs. 124, 125; pl. vii, figs. 153, 154 (1887).
_Plumatella vesicularis_, Braem, Unters. ü. Bryozoen süssen
Wassers, p. 8, pl. i, fig. 8 (Bibl. Zool. ii) (1890).
_Hyalinella punctata_, Loppens, Ann. Biol. lacustre, iii, p.
163 (1908).
_Plumatella punctata_, Annandale, Rec. Ind. Mus. v, p. 52
(1910).
_Zoarium._ The zoarium is entirely recumbent and often appears to form
an almost uniform flat layer instead of a dendritic body. Sometimes,
however, it is distinctly linear, with lateral branches produced
irregularly at considerable distances apart.
_Zooecia._ The zooecia differ from those of all other species in having
a greatly swollen, soft ectocyst which can be transversely wrinkled all
over the zooecium by the action of the muscles of the polypide and is
distinctly contractile. It is mainly owing to the swollen and almost
gelatinous nature of the ectocyst that the dendritic character of the
zoarium is frequently concealed, for the method of branching is
essentially the same as that of _P. diffusa_, although the zooecia are
not so distinctly elbowed. The ectocyst is colourless or faintly tinted
with brown; as a rule it is not quite hyaline and the external surface
is minutely roughened or tuberculate. The zooecia are not emarginate or
furrowed.
_Statoblasts._ Stationary statoblasts are not found. The free
statoblasts are variable and often asymmetrical in outline, but the free
portion of the swim-ring is always of nearly equal diameter all round
the periphery and the capsule relatively large. Some of the statoblasts
are always broad in comparison with their length.
_Polypide._ The polypide is comparatively short and stout. European
specimens are said to have from 30 to 40 tentacles, but Indian specimens
have only from 20 to 30.
Shrunken specimens of the less congested forms of this species closely
resemble specimens of _P. repens_, but the statoblasts are more variable
in shape and the ectocyst, even in such specimens, is thicker. Living or
well-preserved specimens cannot be mistaken for those of any other
species. Jullien regarded _P. punctata_ as the type of a distinct genus
(_Hyalinella_) but included in _Plumatella_ at least one form (P.
"_arethusa_") which probably belongs to this species. Kraepelin
distinguishes as "varieties" two phases, a summer phase ("var.
_prostrata_") and an autumn phase ("var. _densa_"). The former often
forms linear series of considerable length with only an occasional
side-branch, while in the autumn phase branching is so profuse and the
branches are so closely pressed together that the zoarium comes to
resemble a uniform gelatinous patch rather than a dendritic growth. A
phase resembling the European autumn form is the commonest in Calcutta
and I have also found one intermediate between this and Kraepelin's
"var. _prostrata_," neither having any seasonal significance in India.
GEOGRAPHICAL DISTRIBUTION.--_P. punctata_ is widely distributed in
Europe and N. America, but in the Oriental Region it has only been found
in Calcutta and the neighbourhood.
BIOLOGY.--In this part of India _P. punctata_ flourishes both during the
"rains" and in winter. I have found specimens in June and July and also
in December and January. The majority of them were attached to bricks,
but some were on the roots of duckweed, the stems of water-plants, and
the tips of creepers falling into water. The species is often found
together with _Stolella indica_ and also with other species of its own
genus. It is most common, in the neighbourhood of Calcutta, in that part
of the town which is near the Salt Lakes, and occurs in ponds the water
of which is slightly brackish.
Genus 2. STOLELLA, _Annandale_.
_Stolella_, Annandale, Rec. Ind. Mus. iii, p. 279 (1909).
_Stolella_, _id._, _ibid._ v, p. 53 (1910).
TYPE, _Stolella indica_, Annandale.
_Zoarium_. The zoarium consists of groups of zooecia (or occasionally of
single zooecia) joined together by an adherent rhizome. There is no
gelatinous investment.
_Zooecia._ The adult zooecia resemble those of _Plumatella_ except in
being sometimes more or less upright.
_Polypide_ and _Statoblasts._ The polypide and statoblasts resemble
those of _Plumatella_. Fixed as well as free statoblasts occur.
This genus is closely allied to _Plumatella_, from which it is probably
derived. The root-like tube from which the zooecia arise is formed by
the great elongation of the basal part of a zooecium, and the zoaria
closely resemble those of _P. punctata_, for it is not until several
zooecia have been produced that the characteristic mode of growth
becomes apparent.
_Stolella_ has only been found in India and is monotypic[BJ].
[Footnote BJ: But see p. 246 (addenda).]
36. Stolella indica, _Annandale_. (Plate V, figs. 3, 4.)
_Stolella indica_, Annandale, Rec. Ind. Mus. iii, p. 279, fig. (1909).
_Stolella indica_, _id._, _ibid._ v, p. 53 (1910).
_Zoarium._ The zoarium is adherent and linear, having neither lateral
nor vertical branches.
_Zooecia._ The zooecia are short and slender, erect or nearly so,
distinctly emarginate and furrowed. Their ectocyst is soft, colourless
and transparent but minutely roughened on the surface.
_Polypide._ The tentacles number from 30 to 35 and are rather short and
stout, sometimes being slightly expanded at the tips. The stomach is
comparatively short and abruptly truncated posteriorly.
_Statoblasts._ Both free and fixed statoblasts are found, and both are
variable in form, the latter varying in outline from the circular to the
broadly oval. The free statoblasts resemble those of _Plumatella
punctata_, but are sometimes rather more elongate.
TYPE in the Indian Museum.
[Illustration: Fig. 45.--Zoarium of _Stolella indica_ on stem of
water-plant (from Calcutta), × 6.]
GEOGRAPHICAL DISTRIBUTION.--So far as we know, this species is confined
to the Indo-Gangetic Plain. Major Walton found it at Bulandshahr in the
United Provinces, and it is not uncommon in the neighbourhood of
Calcutta.
BIOLOGY.--The zoaria of _S. indica_ are usually fixed to the roots of
duckweed or to the stems of other plants. They are often found together
with those of _P. punctata_. A slight infusion of brackish water into
the ponds in which it lives does not seem to be inimical to this
species, but I have found it in ponds in which nothing of the kind was
possible. It flourishes during the "rains" and, to judge from specimens
kept in an aquarium, is very short-lived. Major Walton found it growing
over a zoarium of _Hislopia lacustris_.
Subfamily B. LOPHOPINÆ.
The zoaria of this subfamily are never dendritic but form gelatinous
masses which, except in _Australella_, are cushion-shaped or sack-like.
With the possible exception of _Australella_, they possess to a limited
extent the power of moving along vertical or horizontal surfaces, but it
is by no means clear how they do so (see p. 172). The statoblasts are
remarkable for their large size, and it is noteworthy that
_Australella_, which is intermediate in structure between the
Plumatellinæ and the Lophopinæ, possesses statoblasts of intermediate
size. The swim-ring is always well developed, and fixed statoblasts are
unknown.
Only two genera (_Lophopodella_ and _Pectinatella_) have been definitely
proved to occur in India, but a third (_Lophopus_[BK]) is stated to have
been found in Madras. Should it be met with it will easily be recognized
by the upright position of its polypides when their tentacles are
expanded and by the fact that the statoblasts never bear marginal
processes.
[Footnote BK: Only two species are known, _L. crystallinus_
(Pallas) from Europe and N. America, with oval statoblasts
that are produced and pointed at the two ends, and _L.
jheringi_, Meissner from Brazil, with irregularly polygonal
or nearly circular statoblasts.]
Genus 3. LOPHOPODELLA, _Rousselet_.
_Lophopodella_, Rousselet, Journ. Quek. Micr. Club (2) ix,
p. 45 (1904).
_Lophopodella_, Annandale, Rec. Ind. Mus. v, p. 54 (1910).
TYPE, _Pectinatella carteri_, Hyatt.
_Zoarium._ The zoarium consists of a circular or oval mass of no great
size. Polyparia do not form compound colonies.
_Polypides._ The polypides lie semi-recumbent in the mass and never
stand upright in a vertical position.
_Statoblasts._ The statoblasts are of considerable size and normally
bear at both ends a series of chitinous processes armed with double rows
of small curved spinules.
As a rule the genus is easily recognized by means of the statoblasts,
but sometimes the processes at the ends of these structures are absent
or abortive and it is then difficult to distinguish them from those of
_Lophopus_. There is, however, no species of that genus known that has
statoblasts shaped like those of the Indian species of _Lophopodella_.
Three species of _Lophopodella_, all of which occur in Africa, have been
described; _L. capensis_ from S. Africa, which has the ends of the
statoblast greatly produced, _L. thomasi_ from Rhodesia, in which they
are distinctly concave, and _L. carteri_ from E. Africa, India and
Japan, in which they are convex or truncate.
The germination of the gemmule and the early stages in the development
of the polyparium of _L. capensis_ have been described by Miss Sollas
(Ann. Nat. Hist. (8) ii, p. 264, 1908).
37. Lophopodella carteri (_Hyatt_). (Plate III, figs. 4, 4_a_.)
_Lophopus_ sp., Carter, Ann. Nat. Hist. (3) iii, p. 335, pl.
viii, figs. 8-15 (1859).
? _Lophopus_ sp., Mitchell, Q. J. Micr. Sci. London (3) ii,
p. 61 (1862).
_Pectinatella carteri_, Hyatt, Comm. Essex Inst. iv, p. 203
(footnote) (1866).
_Pectinatella carteri_, Meissner, Die Moosthiere
Ost-Afrikas, p. 4 (in Mobius's Deutsch-Ost-Afrika, iv,
1898).
_Lophopodella carteri_, Rousselet, Journ. Quek. Micr. Club,
(2) ix, p. 47, pl. iii, figs. 6, 7 (1904).
_Lophopus carteri_, Annandale, Rec. Ind. Mus. ii, p. 171,
fig. 3 (1908).
_Lophopodella carteri_, _id._, _ibid._ v, p. 55 (1910).
_Zoarium._ The zoarium as a rule has one horizontal axis longer than the
other so that it assumes an oval form when the polypides are expanded;
when they are retracted its outline is distinctly lobular. Viewed from
the side it is mound-shaped. The polypides radiate, as a rule in several
circles, from a common centre. The ectocyst is much swollen, hyaline and
colourless.
_Polypide._ The polypide has normally about 60 tentacles, the velum at
the base of which is narrow and by no means strongly festooned. The
stomach is yellow or greenish in colour. The extended part of the
polypide measures when fully expanded rather less than 3 mm., and each
limb of the lophophore about the same.
_Statoblast._ The statoblast is variable in shape and size but measures
on an average about 0.85 × 0.56 mm. The ends are truncate or
subtruncate; the capsule is small as compared with the swim-ring and as
a rule circular or nearly so. The processes at the two ends are variable
in number; so also are their spinules, which are arranged in two
parallel rows, one row on each side of the process, and are neither very
numerous nor set close together; as a rule they curve round through the
greater part of a circle and are absent from the basal part of the
process.
[Illustration: Fig. 46.--Lophopodella carteri (from Igatpuri Lake).
A=outline of a zoarium with the polypides expanded, as seen from below
through glass to which it was attached, × 4; B=outline of a zoarium with
the polypides highly contracted, as seen from above, × 4; C=statoblast,
× 75.]
37 _a._ Var. himalayana.
_Lophopus lendenfeldi_, Annandale (_nec_ Ridley), J. As.
Soc. Bengal, (n. s.) iii, 1907, p. 92, pl. ii, figs. 1-4
(1907).
_Lophopus lendenfeldi_ var. _himalayanus_, _id._, Rec. Ind.
Mus. i, p. 147, figs. 1, 2 (1907).
_Lophopus himalayanus_, _id._, _ibid._ ii, p. 172, fig. 4
(1908).
This variety differs from the typical form in having fewer tentacles and
in the fact that the marginal processes of the statoblast are abortive
or absent.
_Pectinatella davenporti_, Oka[BL] from Japan is evidently a local race
of _L. carteri_, from the typical form of which it differs in having the
marginal processes of the statoblast more numerous and better developed.
The abortive structure of these processes in var. _himalayana_ points to
an arrest of development, for they are the last part of the statoblast
to be formed.
[Footnote BL: Zool. Anz. xxxi, p. 716 (1907), and Annot.
Zool. Japon. vi, p. 117 (1907).]
TYPES. The statoblasts mounted in Canada balsam by Carter and now in the
British Museum must be regarded as the types of the species named but
not seen by Hyatt. The types of the var. _himalayana_ are in the Indian
Museum and those of the subspecies _davenporti_ presumably in the
possession of Dr. Oka in Tokyo.
GEOGRAPHICAL DISTRIBUTION.--The typical form occurs in Bombay, the W.
Himalayas and possibly Madras, and its statoblasts have been found in E.
Africa; the var. _himalayana_ has only been taken in the W. Himalayas
and the subspecies _davenporti_ in Japan. Indian localities are:--BOMBAY
PRESIDENCY, Igatpuri Lake, W. Ghats (alt. _ca._ 2,000 feet); the Island
of Bombay (_Carter_): W. HIMALAYAS, Bhim Tal, Kumaon (alt. 4,500 feet).
BIOLOGY.--_L. carteri_ is found on the lower surface of stones and on
the stems and leaves of water-plants, usually in lakes or large ponds.
Although the zoaria do not form compound colonies by secreting a common
membrane or investment, they are markedly gregarious. The most closely
congregated and the largest zoaria I have seen were assembled amongst a
gelatinous green alga of the genus _Tolypothrix_[BM] (Myxophyceæ) that
grows on the vertical stems of a plant at the edge of Igatpuri Lake; it
is noteworthy that in this case the alga seemed to take the place of the
common investment of _Pectinatella burmanica_, in which green cells are
present in large numbers (p. 237). The zoaria of _L. carteri_ are able
to change their position, and I found that if a number of them were
placed in a bottle of water they slowly came together at one spot, thus
apparently forming temporary compound colonies. Before a movement of the
whole zoarium commences its base becomes detached from its support at
the anterior end (fig. 32, p. 172), but the whole action is extremely
slow and I have not been able to discover any facts that cast light on
its exact method of production. At Igatpuri statoblasts are being
produced in considerable numbers at the end of November, but many young
zoaria can be found in which none have as yet been formed.
[Footnote BM: Prof. W. West will shortly describe this alga,
which represents a new species, in the Journ. Asiat. Soc.
Bengal, under the name _Tolypothrix
lophopodellophila_.--_April 1911_.]
The larva of a fly of the genus _Chironomus_ is often found inhabiting a
tube below zoaria of _L. carteri_. It is thus protected from its enemies
but can protrude its head from beneath the zoarium and seize the small
animals on which it preys.
Genus 4. PECTINATELLA, _Leidy_.
_Cristatella_, Leidy, P. Ac. Philad. v, p. 265 (1852).
_Pectinatella_, _id._, _ibid._, p. 320.
_Pectinatella_, Allman, Mon. Fresh-Water Polyzoa, p. 81
(1857).
_Pectinatella_, Hyatt, Proc. Essex Inst. v, p. 227, fig. 20
(1867).
_Pectinatella_, Kraepelin, Deutsch. Süsswasserbryozoen, i,
p. 133 (1887).
_Pectinatella_, Oka, Journ. Coll. Sci. Tokyo, iv, p. 89
(1891).
TYPE, _Pectinatella magnifica_, Leidy.
This genus is closely allied to _Lophopodella_, from which it is often
difficult to distinguish young specimens. Adult zoaria are, however,
always embedded together in groups in a gelatinous investment which they
are thought to secrete in common[BN], and the statoblasts are entirely
surrounded by processes that bear curved spinules at their tips only.
The polypides have the same semi-recumbent position as those of
_Lophopodella_ but are larger than those of any species of
_Lophopodella_ or _Lophopus_ yet known. The statoblasts are larger than
those of any other Plumatellidæ.
[Footnote BN: It is now perhaps open to doubt whether the
investment is actually secreted by the polyzoon, for Prof.
W. West has discovered in it the cells of an alga belonging
to a genus which habitually secretes a gelatinous investment
of its own (see p. 238, _post._).--_April 1911._]
The type-species was originally found in N. America but has since been
taken in several localities in continental Europe. Except this and the
Indian form only one species is known, namely _P. gelatinosa_ from
Japan. _P. magnifica_ has circular statoblasts with long marginal
processes, while in _P. gelatinosa_ the statoblasts are subquadrate and
in _P. burmanica_ almost circular, both Asiatic forms having very short
marginal processes.
The compound colonies formed by _Pectinatella_ are often of great size.
Those of _P. gelatinosa_ are sometimes over 2 metres in length, while
those of _P. burmanica_ in the Sur Lake appeared to be only limited as
regards their growth by the shallowness of the water in which the reeds
to which they were attached were growing. Some were observed that were
over 2 feet long.
38. Pectinatella burmanica, _Annandale_. (Plate III, fig. 5.)
_Pectinatella burmanica_, Annandale, Rec. Ind. Mus. ii,
p. 174, fig. 5 (1908).
_Pectinatella burmanica_, _id._, _ibid._ v, p. 56 (1910).
_Pectinatella burmanica_, _id._, Spol. Zeyl. vii, p. 63,
pl. i, fig. 3 (1910).
_Zoarium._ The zoaria are circular or nearly so except when about to
undergo division, in which case they are constricted in the middle. As a
rule they measure nearly an inch (2 cm.) in diameter. The polypides have
a definite arrangement in each zoarium, being divided into four groups,
each of which has a fan-like form. In the first place they are separated
into two main divisions in a line running through the centre of the
zoarium, and secondly each main division is separated into two
subordinate ones in a line running across the other at right angles. The
number of zoaria joined together in a single compound colony is very
variable; sometimes there are only about half a dozen and sometimes
several hundreds. The common investment in living colonies is often as
much as two inches thick and has a translucent dark greenish colour due
to the presence in it of green cells.
[Illustration: Fig. 47.--_Pectinatella burmanica._
A=polypide with the lophophore expanded, × 15; _a_=oesophagus;
_b_=cardiac limb of stomach; _c_=stomach; _d_=rectum; _e_=anus;
_f_=funiculus. [The muscles are omitted and the external tubercles are
only shown on part of the polypide. The specimen is from the Sur Lake,
Orissa.] B=statoblast from Ceylon, × 35.]
_Polypide._ The polypide can be extruded for a distance of at least 5
mm. Its whole external surface is covered with minute tubercles. There
are about 90 tentacles, which are long and slender, the velum at their
base being narrow and almost straight. The stomach is of considerable
stoutness.
_Statoblast._ The statoblasts are of large size, measuring from 1 to
1.75 mm. in diameter. In form they are almost circular, but one side is
always slightly flattened. The marginal processes are very short and
bear a single pair of hooks at the tip. The capsule is circular and
small as compared with the free part of the swim-ring.
TYPE in the Indian Museum.
_P. burmanica_ is evidently a near relation of _P. gelatinosa_, Oka,
from Japan, differing from that species in the shape of the statoblasts
and in having much longer tentacles. The arrangement of the polypides in
the zoarium and the general structure of the statoblasts are very
similar in the two species.
GEOGRAPHICAL DISTRIBUTION.--_P. burmanica_ was originally described from
a swamp at Kawkareik in the Amherst district of Tenasserim but has also
been found in the Sur Lake near Puri in Orissa. Dr. A. Willey obtained
specimens from a pool by the roadside between Maradankadewela and
Galapitagala, at the foot of Ritigala, N. Central Province, Ceylon.
BIOLOGY.--The first specimen obtained was a statoblast fixed to a tube
of the oligochæte worm _Aulophorus tonkinensis_ taken at Kawkareik in
March. At the same time young zoaria, which did not yet possess a common
investment, were found on a leaf growing on a twig which drooped into
the water. Large compound colonies were taken in Orissa in October. They
completely encased the stems of reeds, thus forming hollow cylinders,
but slipped from their supports when the reeds were pulled out of the
water. In life they resembled gelatinous algæ rather than animals and
exhibited a striking similarity to masses of zoaria of _Lophopodella
carteri_ surrounded by such algæ. Some of the colonies were evidently
dying and contained few polypides in a living condition, but many
statoblasts; others were in a flourishing condition and were producing
larvæ and statoblasts simultaneously.
A piece of a colony full of larvæ was placed before midday in an
aquarium, which was kept in a shady verandah. Large numbers of larvæ
were set free almost immediately. They measured about 2 mm. in length
and were distinctly pear-shaped; each contained a pair of polypides,
which occupied a comparatively small part of the interior, the whole of
the broader half being hollow. The larvæ swam slowly, broad-end-first,
by means of the cilia with which their surface was covered, occasionally
gyrating on their long axis and always adopting an erratic course.
Towards evening they showed signs of settling down, frequently touching
the glass of the aquarium with their broad ends and sometimes remaining
still in this position for some minutes. Many attempts were, however,
made before fixation was completed, and this did not occur until after
nightfall. By next morning every larva was fixed to the glass and had
everted its two polypides. Unfortunately I was not able to trace the
development further, but young compound colonies were found in which the
secretion of the common investment had just commenced. The zoaria in
these colonies measured about 1 cm. in diameter and already contained
many polypides each.
Oka has described the development from the statoblast of the allied
Japanese species. He found that each statoblast produced in the first
instance a single polypide, and that the statoblasts, which were
produced in autumn, lay dormant through the winter and germinated in
spring. As the Sur Lake begins to undergo desiccation as soon as the
"rains" cease, the statoblasts in it probably do not germinate until the
break of the next "rains" about the middle of June. I have had dried
statoblasts in my possession for over two years. Their cellular contents
appear to be in good condition, although the cells show no signs of
development; but they have not germinated in my aquarium, in which some
of them have now been kept for more than six months.
The green cells of the common investment are peculiar bodies that
deserve further study than it has yet been possible to devote to them.
Each cell is of ovoid form, varying somewhat in size but as a rule
measuring about 0.03 × 0.008 mm. There can be no doubt that these bodies
represent a stage in the life-history of an alga[BO]. Diatoms, bacilli
and other minute plants are often present in the membrane as well as the
characteristic green cells, but do not form a constant feature of it.
[Footnote BO: Professor W. West identifies this algæ as
_Dactylococcopsis pectinatellophila_, new species. It will
be described, before the publication of this book, in the
Journ. As. Soc. Bengal (1911). Prof. West has found,
associated more or less fortuitously with _P. burmanica_,
another alga, namely _Microcystis orissica_, also a new
species.--_April 1911._]
APPENDIX TO THE VOLUME.
HINTS ON THE PREPARATION OF SPECIMENS.
_To preserve Spongillidæ._--Spongillidæ must be preserved dry or in very
strong alcohol. Formalin should not be used.
_To clean siliceous sponge spicules._--Place small fragments of the
dried sponge (if alcohol is present, the reaction is apt to be violent)
in a test tube, cover them with strong nitric acid and boil over the
flame of a Bunsen burner or small spirit lamp until the solid particles
disappear. Add a large quantity of water to the acid and filter through
pure cellulose filter-paper, agitating the liquid repeatedly. Pass clean
water in considerable quantities through the filter-paper and dry the
latter carefully; place it in a spirally coiled wire and ignite with a
match, holding the wire in such a way that the spicules released by the
burning of the paper fall into a suitable receptacle. They may then be
picked up with a camel's-hair brush and mounted in Canada balsam.
_To examine the skeleton of a Spongillid._--Cut thin hand-sections with
a sharp scalpel, dehydrate if necessary, and mount in Canada balsam.
_To prepare gemmules for examination._--Place the gemmules dry in a
watch-glass with a few drops of strong nitric acid. When gas is given
off freely add water in considerable quantities. Remove the gemmules
with a camel's-hair brush to clean water, then to 50%, 70%, 90% and
absolute alcohol in succession, leaving them for an hour in each
strength of spirit. Clear with oil of cloves and mount in Canada balsam.
_To ascertain the presence of bubble-cells in the parenchyma of a
Spongillid._--Tease up a small piece of the sponge with a pair of
needles, mount under a thin cover-slip in strong spirit, and examine
under a high power of the microscope.
_To preserve Hydra in an expanded condition._--Place the polyp in a
watch-glass of clean water and wait until its tentacles are expanded.
Heat a few drops of commercial formaldehyde and squirt the liquid while
still hot at the _Hydra_, which will be killed instantaneously. Remove
it to a solution of formaldehyde and spirit of the following formula:--
Commercial formaldehyde 1 part.
Absolute alcohol 3 parts.
Distilled water 7 parts.
Then pass the _Hydra_ through 50% and 70% alcohol and keep in 90%.
_To examine the capsules of the nettle-cells._--Place a living _Hydra_
in a small drop of water on a slide and press a thin cover-slip down
upon it.
_To preserve freshwater polyzoa in an expanded condition._--Place the
polyzoa in a glass tube full of clean water and allow them to expand
their tentacles. Drop on them gradually when they are fully expanded a
2% aqueous solution of cocaine, two or three drops at a time, until
movement ceases in the tentacles. Then pour commercial formaldehyde into
the tube in considerable quantities. Allow the whole to stand for half
an hour. If it is proposed to stain the specimens for anatomical
investigation, they should then be removed through 50% and 70% to 90%
alcohol. If, on the other hand, it is desired to keep them in a
life-like condition they may be kept permanently in a solution of one
part of commercial formaldehyde in four parts of water. Care must be
taken that the process of paralyzing the polypides is not unduly
prolonged, and it is always as well to preserve duplicate specimens in
spirit or formalin with the lophophore retracted.
_To prepare statoblasts for examination._--Place the statoblasts for a
few minutes in strong nitric acid. Then remove the acid with water, pass
through alcohol, clear with oil of cloves, and mount in a small quantity
of Canada balsam under a cover-slip, taking care that the statoblasts
lie parallel to the latter.
ADDENDA.
The following addenda are due mainly to an expedition to the lakes of
Kumaon in the W. Himalayas undertaken by Mr. S. W. Kemp in May, 1911.
PART I.
Genus SPONGILLA.
Subgenus EUSPONGILLA (p. 69).
1 a. Spongilla lacustris, subsp. reticulata (p. 71).
Specimens were taken in the lake Malwa Tal (alt. 3600 feet) in Kumaon,
while others have recently been obtained from the Kalichedu
irrigation-tank in the Pagnor _talug_ of the Nellore district, Madras
(_G. H. Tipper_).
4. Spongilla cinerea (p. 79).
Specimens were taken in Naukuchia Tal (alt. 4200 feet) in Kumaon. They
have a pale yellow colour when dry. This sponge has not hitherto been
found outside the Bombay Presidency.
Subgenus EUNAPIUS (p. 86).
8. Spongilla carteri (p. 87).
Specimens were taken in Bhim Tal (alt. 4450 feet) and Sat Tal (alt. 4500
feet). Some of them approach the variety _cava_ in structure.
Subgenus STRATOSPONGILLA (p. 100).
12. Spongilla bombayensis (p. 102).
Add a new variety:--
13 a. Var. pneumatica, nov.
(i.) The sponge forms a flat layer of a pale brownish colour
as a rule with short and very delicate vertical branches.
In one specimen it takes the form of an elegant cup
attached, only at the base, to a slender twig.
(ii.) The gemmules are covered, outside the spicules, by a
thick pneumatic coat of irregular formation and with
comparatively large air-spaces.
(iii.) The gemmule-spicules are regularly sausage-shaped.
TYPES in the Indian Museum.
HABITAT. Naukuchia Tal (alt. 4200 feet), Kumaon, W. Himalayas (_S. W.
Kemp_).
Genus EPHYDATIA (p. 108).
After _Ephydatia meyeni_, p. 108, add:--
Ephydatia fluviatilis, _auct._
? _Ephydatia fluviatilis_, Lamouroux, Encyclop. Méthod. ii,
p. 327 (1824).
_Spongilla fluviatilis_, Bowerbank (_partim_), Proc. Zool.
Soc. London, 1863, p. 445, pl. xxxviii, fig. 1.
_Ephydatia fluviatilis_, J. E. Gray (_partim_), Proc. Zool.
Soc. London, 1867, p. 550.
_Meyenia fluviatilis_, Carter (_partim_), Ann. Nat. Hist.
(5) vii, p. 92, pl. vi, fig. 11 _a_, _b_ (1881).
_Ephydatia fluviatilis_, Vejdovsky, Abh. k. Böhm.
Gesellschaft Wiss. xii, p. 24, pl. i, figs. 1, 2, 7, 10, 14,
19 (1883).
_Ephydatia fluviatilis_, _id._, P. Ac. Philad. 1887, p. 178.
_Meyenia fluviatilis_ var. _gracilis_, Potts, _ibid._, p.
224.
_Meyenia robusta_, _id._, _ibid._, p. 225, pl. ix, fig. 5.
_Ephydatia fluviatilis_, Weltner, Arch. Naturg. Berlin, 1895
(i) p. 122.
_Ephydatia robusta_, Annandale, Journ. As. Soc. Bengal,
1907, p. 24, fig. 7.
_Ephydatia fluviatilis_, Weltner, in Brauer's
Süsswasserfauna Deutschlands xix, Süsswasserschwämme, p.
185, figs. 316, 317 (1909).
_Ephydatia fluviatilis_, Annandale, P. U. S. Mus. xxxviii,
p. 649 (1910).
[Many more references to this common species might be cited, but those
given above will be sufficient.]
This species only differs from _E. meyeni_ in the following
characters:--
(i.) there are no bubble-cells in the parenchyma;
(ii.) there is less spongin in the skeleton, which is less compact;
(iii.) the gemmule-spicules are longer, the shafts being as a rule
longer than the diameter of the rotulæ;
(iv.) the gemmules are armed with a single row of regularly
arranged spicules embedded in pneumatic tissue with
minute air-spaces.
The sponge is a variable one and several "varieties" have been described
from different parts of the world. My Indian specimens come nearest to
the form described by Potts as _Meyenia robusta_, but have rather more
slender skeleton-spicules and more elongate gemmule-spicules. The latter
also appear to be less frequently "monstrous."
TYPE ?
GEOGRAPHICAL DISTRIBUTION.--_E. fluviatilis_ is widely distributed in
Europe and occurs in N. America,[BP] S. Africa (var. _capensis_,
Kirkpatrick), Australia, and Japan. Specimens were obtained by Mr. Kemp
from several lakes in Kumaon, namely Naukuchia Tal (alt. 4200 feet),
Bhim Tal (4450 feet), Sat Tal (4500 feet), and Naini Tal (6300 feet).
The gemmules from Bhim Tal referred by me to _E. robusta_ (Potts) also
belong to this species.
[Footnote BP: Most of the forms assigned by Potts to this
species belong to the closely allied _E. mülleri_
(Lieberkühn).]
_Biology._ The external form of the sponge is due in great part to its
environment. Specimens on small stones from the bottom of the Kumaon
Lakes consist of thin disk-like films, often not more than a few
centimetres in diameter and a few millimetres thick: others, growing on
thin twigs, are elevated and compressed, resembling a cockscomb in
appearance, while others again form nodules and masses of irregular form
among the branches of delicate water-weeds. Some of these last are
penetrated by zoaria of _Fredericella indica_.
Weltner has published some very interesting observations on the seasonal
variation of minute structure in European representatives of the species
(Arch. Naturg. Berlin, lxxiii (i), p. 273 1907) and has discussed the
formation of the abnormal spicules that sometimes occur (_ibid._ lxvii
(Special Number), p. 191, pls. vi, vii, figs. 27-59, 1901).
Genus CORVOSPONGILLA (p. 122).
After _Corvospongilla burmanica_, p. 123, add a new species:--
Corvospongilla caunteri, nov.
_Sponge_ forming thin films of considerable area not more than 3 or 4
mm. thick, of a bright green colour, moderately hard but friable. The
surface smooth; oscula inconspicuous, surrounded by shallow and
ill-defined radiating furrows; a very stout basal membrane present.
[Illustration: Fig. 48.--_Corvospongilla caunteri_ (type, from Lucknow).
A=Gemmule; B=gemmule-spicules; C=flesh-spicules; D=Skeleton-spicules.]
_Skeleton_ reticulate but almost devoid of spongin, the reticulations
close but formed mainly by single spicules; skeleton-fibres barely
distinguishable. A close layer of spicules lying parallel to the basal
membrane.
_Spicules._ Skeleton-spicules variable in size and shape, almost
straight, as a rule smooth, moderately stout, blunt or abruptly pointed;
sometimes roughened or spiny at the tips, often sharply pointed.
Flesh-spicules minute, few in number, with smooth, slender shafts which
are variable in length, never very strongly curved; the terminal spines
relatively short, not strongly recurved. Gemmule-spicules
amphistrongylous or amphioxous, irregularly spiny, slender, of variable
length.
_Gemmules_ free in the substance of the sponge, spherical or somewhat
depressed, very variable in size but never large, having a thick
external pneumatic coat in which the air-spaces are extremely small and,
inside this coat, a single rather sparse layer of spicules lying
parallel to the gemmule. A single depressed aperture present.
TYPE in the Indian Museum.
HABITAT. Hazratganj, Lucknow; on piers of bridge in running water (_J.
Caunter_, 29-30. iv. 11).
The structure of the gemmules of this species differs considerably from
that in any other known species of the genus, in which these structures
are usually adherent and devoid of a true pneumatic coat. In some of the
gemmules before me this coat measures in thickness about 1/9 of the
total diameter of the gemmule. _C. caunteri_ is the first species of
_Corvospongilla_ to be found in the Indo-Gangetic plain.
PART II.
Genus HYDRA (p. 147).
25. Hydra oligactis (p. 158).
Mr. Kemp found this species common in Bhim Tal in May. His specimens,
which were of a reddish-brown colour in life, appear to have been of
more vigorous constitution than those taken by Major Stephenson in
Lahore. Some of them had four buds but none were sexually mature.
PART III.
Genus FREDERICELLA (p. 208).
28. Fredericella indica (p. 210).
This species is common in some of the Kumaon lakes, in which it grows,
at any rate at the beginning of summer, much more luxuriantly than it
does in the lakes of the Malabar Zone in autumn, forming dense bushy
masses on the under surface of stones, on sticks, &c. The vertical
branches often consist of many zooecia. Mr. Kemp took specimens in Malwa
Tal, Sath Tal, and Naini Tal (alt. 3600-6300 feet).
Genus PLUMATELLA (p. 212).
30. Plumatella emarginata (p. 220).
Mr. Kemp took bushy masses of this species in Malwa Tal and Bhim Tal.
32. Plumatella diffusa (p. 223).
This species is common in Malwa Tal and Bhim Tal in May.
33. Plumatella allmani (p. 224).
Mr. Kemp only found this species in Malwa Tal, in which (at any rate in
May) it appears to be less abundant than it is in Bhim Tal in autumn.
Mr. Kemp's specimens belong to the form called _P. elegans_ by Allman.
34. Plumatella tanganyikæ (p. 225).
Specimens taken by Mr. Kemp, somewhat sparingly, in Bhim Tal and Sath
Tal in May exhibit a somewhat greater tendency towards uprightness of
the zooecia than those I found in autumn in Igatpuri lake. The ectocyst
is, in the former specimens, of a deep but bright reddish-brown. The
zoaria are attached to twigs and small stones.
Genus STOLELLA (p. 229).
After Stolella indica, p. 229, add a new species:--
Stolella himalayana, nov.
This species may be distinguished from _S. indica_ by (i) its entirely
recumbent zooecia, and (ii) the lateral branches of its zoarium.
[Illustration: Fig. 49.--_Stolella himalayana_ (types, from the Kumaon
lakes).
A. The greater part of a young zoarium. B. Part of a much older
zoarium.]
_Zoarium_ entirely recumbent, consisting of zooecia joined together,
often in groups of three, by slender, transparent, tubular processes.
These processes are often of great relative length; they are formed by a
modification of the posterior or proximal part of the zooecia, from
which they are not separated by a partition, and they increase in length
up to a certain point more rapidly than the zooecia proper. A zooecium
often gives rise first to an anterior daughter-zooecium, the proximal
part of which becomes elongate and attenuated in due course, and then to
a pair of lateral daughter-zooecia situated one on either side. As a
result of this method of budding a zoarium with a close superficial
resemblance to that of _Paludicella_ is at first produced, but as the
colony increases in age and complexity this resemblance largely
disappears, for the zooecia and their basal tubules grow over one
another and often become strangely contorted (fig. 49).
_Zooecia_ elongate and slender, flattened on the ventral, strongly
convex on the dorsal surface; rather deep in proportion to their
breadth; the ectocyst colourless, not very transparent except on the
stolon-like tubular part; dorsal keel and furrow as a rule absent;
orifice unusually inconspicuous, situated on a tubercle on the dorsal
surface.
_Polypide_ stout and short; the tip of the fundus of the stomach capable
of very complete constriction; the retractor muscles unusually short and
stout.
_Statoblasts._ Only free statoblasts have been observed. They resemble
those of _S. indica_, but are perhaps a little longer and more elongate.
TYPES in the Indian Museum.
The discovery of this species makes it necessary to modify the diagnosis
of the genus, the essential character of which, as distinguishing it
from _Plumatella_, is the differentiation of the proximal part of some
or all of the zooecia to form stolon-like tubules. From _Stephanella_,
Oka, it is distinguished by the absence of a gelatinous covering, and by
the fact that all the zooecia are attached, at least at the base, to
some extraneous object.
HABITAT. Malwa Tal, Kumaon (alt. 3600 feet), W. Himalayas (_Kemp_, May
1911).
BIOLOGY. Mr. Kemp took three specimens, all attached to the lower
surface of stones. They contained few statoblasts and were evidently in
a condition of vigorous growth. Between the lateral branches new
polyparia were developing in several instances from free statoblasts,
each of which appeared to contain two polypides.
ALPHABETICAL INDEX.
All names printed in italics are synonyms.
When more than one reference is given, the page on which the description
occurs is indicated by thickened numerals.
alba (Euspongilla) (Spongilla), 8, 9.
alba (Spongilla), 4, 22, 63, ~76~.
alba _var._ bengalensis (Spongilla), 4, 22, 63, ~77~.
alba _var_. cerebellata (Spongilla), 22, 63, ~76~.
_alba_ var. _marina_ (_Spongilla_), ~77~.
_Alcyonella_, 212.
Alcyonellea, 185.
allmani (Plumatella), 7, 8, 9, 23, 188, ~224~, 246.
_allmani_ var. _diffusa_ (_Plumatella_), 223.
_allmani_ var. _dumortieri_ (_Plumatella_), 222.
_attenuata_ (_Hydra_), 148, 158.
_aurantiaca_ (_Hydra_), 148.
aurea (Pectispongilla), 9, 22, 63, ~106~.
aurea _var._ subspinosa (Pectispongilla), 63, ~107~.
_benedeni_ (_Alcyonella_), 220.
bengalensis (Bowerbankia), 189.
bengalensis (Membranipora), 23.
bengalensis (Spongilla), 77.
bengalensis (Victorella), 4, 8, 9, 23, 187, ~195~.
blembingia (Ephydatia), 54.
bogorensis (Ephydatia), 54.
_bombayensis_ (_Plumatella_), 225.
bombayensis (Spongilla), 22, 63, 100, ~102~, 241.
bombayensis (Stratospongilla) (Spongilla), 8, 9.
Bowerbankia, 187, ~189~.
_brunnea_ (_Hydra_), 148.
burmanica (Corvospongilla), 8, 22, 64, ~122~.
burmanica (Pectinatella), 8, 10, 23, 188, ~235~.
calcuttana (Spongilla), 96.
_cambodgiensis_ (_Norodonia_), 202.
_Carterella_, 108.
carteri (Eunapius) (Spongilla), 7, 8, 9, 10.
_carteri_ (_Eunapius_), 87.
carteri (Lophopodella), 7, 8, 23, 188, ~232~, 233.
_carteri_ (_Lophopus_), 232.
_carteri_ (_Pectinatella_), 231,
carteri (Spongilla), 4, 22, 63, 86, ~87~, 241.
carteri _var._ cava (Spongilla), 22, 63.
carteri _var._ himalayana (Lophopodella), 23, 188.
carteri _var._ lobosa (Spongilla), 22, 63.
carteri _var._ mollis (Spongilla), 22, 63.
caudata (Bowerbankia), 189.
caudata _subsp._ bengalensis (Bowerbankia), 23, 189.
caunteri (Corvospongilla), 243.
cava (Spongilla), 88.
cerebellata (Spongilla), 76.
ceylonensis (Irene), 22, 140.
Cheilostomata, 184.
Chlorella, 50.
cinerea (Euspongilla) (Spongilla), 9.
cinerea (Spongilla), 22, 63, 72, 79, 241.
clementis (Stratospongilla) (Spongilla), 53.
coggini (Stratospongilla) (Spongilla), 53.
colonialis (Loxosomatoides), 23.
_contecta_ (_Spongilla_), 95.
_coralloides_ (_Plumatella_), 217.
Corvospongilla, 64, ~122~, 243.
crassior (Spongilla), 98.
crassissima (Eunapius) (Spongilla), 9.
crassissima (Spongilla), 4, 22, 63, ~98~.
crassissima _var._ crassior (Spongilla), 23, 63.
_crateriformis_ (_Meyenia_), 83.
_crateriformis_ (_Ephydatia_), 83, 84.
crateriformis (Euspongilla) (Spongilla), 8, 9.
_crateriformis_ (_Meyenia_), 83.
crateriformis (Spongilla), 22, 63, ~83~.
_Cristatella_, 235.
Cristatellina, 206.
Ctenostomata, 184, 185, 187, ~189~.
Cyclostomata, 184.
decipiens (Spongilla), 54, 96, ~97~.
diffusa (Plumatella), 7, 8, 9, 23, 188, ~223~, 245.
_di[oe]cia_ (_Hydra_), 158.
Dosilia, 64, ~110~.
_Echinella_, 199.
_elegans_ (_Plumatella_), 224.
Eleutheroblastea, 146, 147.
emarginata (Plumatella), 4, 8, 9, 10, 23, 188, 218, ~220~, 245.
_emarginata_ var. _javanica_ (_Plumatella_), 221.
Entoprocta, 183.
Ephydatia, 64, ~108~, 242.
_erinaceus_ (_Spongilla_), 114.
Eunapius, 63, ~86~, 241.
Euspongilla, 63, 67, ~69~, 241.
filamentata (Syncoryne), 22, 140.
fluviatilis (Ephydatia), 109, ~242~.
_fluviatilis_ (_Meyenia_), 242.
fluviatilis (Spongilla), 108, 242.
_fluviatilis_ var. _gracilis_ (_Meyenia_), 242.
fortis (Ephydatia), 52, 53.
fragilis (Spongilla), ~95~, 96.
fragilis _subsp._ calcuttana (Eunapius) (Spongilla), 9.
fragilis _subsp._ calcuttana (Spongilla), 22, 63.
fragilis _subsp._ decipiens (Spongilla), 22, 63.
Fredericella, 188, ~208~, 245.
FREDERICELLIDÆ, 188, ~208~.
_friabilis_ (_Spongilla_), 87.
fruticosa (Plumatella), 4, 7, 8, 9, 23, 188, ~217~, 218.
_fusca_ (_Hydra_), 158, 159.
Gecarcinucus, 10.
gemina (Eunapius) (Spongilla), ~8~.
gemina (Spongilla), 22, 63, ~97~.
_glomerata_ (_Spongilla_), 95.
_grisea_ (_Hydra_), 148, 149.
Gymnolæmata, 184, 187.
Halichondrina, 65.
hemephydatia (Euspongilla) (Spongilla), 8.
hemephydatia (Spongilla), 22, 63, ~82~.
_hexactinella_ (_Hydra_), 148.
himalayana (Lophopodella), 233.
himalayana (Stolella), 246.
_himalayanus_ (_Lophopus_), 233.
Hislopia, 187, ~199~.
Hislopidées, 199.
HISLOPIIDÆ, 187, ~199~.
Homodiætidæ, 191.
_Hyalinella_, 212.
Hydra, 146, ~147~, 245.
Hydraidæ, 147.
HYDRIDÆ, 146, 147.
hydriforme (Polypodium), 142.
Hydrozoa, 146.
_indica_ (_Ephydatia_), 83.
indica (Fredericella), 9, 23, 188, ~209~, 245.
indica (Spongilla), 22, 63, ~100~.
indica (Stolella), 4, 9, 23, 188, ~229~.
indica (Stratospongilla), (Spongilla), 9.
javanica (Plumatella), 4, 8, 9, 23, 188, ~221~, 222.
kawaii (Limnocodium), 141.
lacroixii (Membranipora), 23.
lacustris (Cordylophora), 141.
_lacustris_ (_Euspongilla_), 69.
lacustris (Hislopia), 4, 8, 9, 23, 187, 199, ~202~, 204.
lacustris (Spongilla), 63, 67, ~69~.
lacustris _subsp._ moniliformis (Hislopia), 9, 23, 187.
lacustris _subsp._ reticulata (Spongilla), 4, 8, 9, 22, 63, ~71~, 241.
_lacustris_ var. _bengalensis_ (_Spongilla_), 77.
lapidosa (Corvospongilla), 9, 22, 64, ~124~.
_lapidosa_ (_Spongilla_), 124.
latouchiana (Trochospongilla), 4, 8, 9, 22, 64, ~115~.
_leidyi_ (_Trochospongilla_), 115.
_lendenfeldi_ (_Lophopus_), 233.
_lendenfeldi_ var. _himalayanus_ (_Lophopus_), 233.
lobosa (Spongilla), 89.
LOPHOPINÆ, 188, 211, ~231~.
Lophopodella, 8, 188, ~231~.
_Lophopus_, 8, 232.
_lordii_ (_Spongilla_), 95.
loricata (Spongilla), ~122~.
_loricata_ var. _burmanica_, (_Spongilla_), 122.
_lucifuga_ (_Plumatella_), 217, 220, 224.
magnifica (Pectinatella), 235.
meyeni (Ephydatia), 7, 9, 17, 22, 64, ~108~.
_meyeni_ (_Spongilla_), 108.
_Meyenia_, 108, 113.
microsclerifera (Euspongilla) (Spongilla), 53.
mollis (Spongilla), 88.
moniliformis (Hislopia), 204.
_mon[oe]cia_ (_Hydra_), 158.
_morgiana_ (_Spongilla_), 95.
_mülleri_ (_Ephydatia_), 109, 243.
_mülleri_ subsp. _meyeni_ (_Ephydatia_), 109.
_Norodonia_, 199.
oligactis (Hydra), 7, 22, 146, ~158~, 159, 245.
_orientalis_ (_Hydra_), 148, 149.
_ottavænsis_ (_Spongilla_), 95.
_pallens_ (_Hydra_), 148.
Paludicella, 187, ~192~.
PALUDICELLIDÆ, 187, ~191~.
Paludicellidées, 191.
Paludicellides, 191.
Paludicellina, 186, 187, ~190~.
paulula (Spongilla), 120.
_pavida_ (_Victorella_), 194, 195.
Pectinatella, 188, ~235~.
pectinatellophila (Dactyloccopsis), 238.
Pectispongilla, 63, ~106~.
pennsylvanica (Trochospongilla), 9, 22, 64, ~118~.
_pennsylvanica_ (_Tubella_), 118.
_pentactinella_ (_Hydra_), 149.
philippinensis (Euspongilla) (Spongilla), 53.
phillottiana (Trochospongilla), 4, 8, 9, 22, 64, ~117~.
Phylactolæmata, 185, 188, ~206~.
Plumatella, 188, 208, ~212~, 245.
PLUMATELLIDÆ, 188, ~211~.
Plumatellina, 188, ~206~.
PLUMATELLINÆ, 188, 211, ~212~.
plumosa (Dosilia), 8, 9, 22, 64, ~111~.
_plumosa_ (_Ephydatia_), 111.
_plumosa_ (_Meyenia_), 111.
_plumosa_ (_Spongilla_), 111.
pneumatica (Stratospongilla) (Spongilla), 241.
_polypus_ (_Hydra_), 148, 159.
Polyzoa, 183.
_princeps_ (_Plumatella_), 220.
_princeps_ var. _emarginata_ (_Plumatella_), 220.
_princeps_ var. _fruticosa_ (_Plumatella_), 217.
proliferens (Euspongilla) (Spongilla), 8, 9, 10.
proliferens (Spongilla), 4, 8, 22, 63, ~72~.
Proterospongia, 27.
_punctata_ (_Hyalinella_), 228.
punctata (Plumatella), 9, 188, ~227~.
_repens_ (_Plumatella_), 217, 223.
reticulata (Spongilla), 71.
_rhætica_ (_Hydra_), 158.
_robusta_ (_Ephydatia_), 109, 242.
_robusta_ (_Meyenia_), 242.
_roeselii_ (_Hydra_), 158.
ryderi (Microhydra), 141.
schilleriana (Sagartia), 2, 22, 140.
schilleriana _subsp_. exul (Sagartia), 22.
_sibirica_ (_Spongilla_), 95.
_sinensis_ (_Norodonia_), 202.
sinensis (Stratospongilla) (Spongilla), 53.
_socialis_ (_Hydra_), 158.
sowerbii (Limnocodium), 141.
Spongilla, 63, ~67~, 86, 241.
Spongilladæ, 65.
SPONGILLIDÆ, 65.
Stolella, 188, ~229~, 246.
Stolonifera, 185.
Stratospongilla, 63, ~100~, 241.
_stricta_ (_Plumatella_), 217.
subspinosa (Pectispongilla), 107.
sumatrana (Stratospongilla) (Spongilla), 53.
tanganyikæ (Limnocnida), 142.
tanganyikæ (Plumatella), 9, 23, 188, ~225~, 246.
Trachospongilla, 64, ~113~.
_Trachyspongilla_, 108.
travancorica (Euspongilla) (Spongilla), 9.
travancorica (Spongilla), 22, 63, ~81~.
_trembleyi_ (_Hydra_), 148.
Tubella, 64, 113, ~120~.
ultima (Spongilla), 22, 63, ~105~.
ultima (Stratospongilla) (Spongilla), 9.
VESICULARIDÆ, 189.
Vesicularina, 186, 187, ~189~.
_vesicularis_ (_Hyalinella_), 228.
_vesicularis_ (_Plumatella_), 227, 228.
vesparioides (Tubella), 8, 22, 64, ~120~.
vesparium (Tubella), 54.
vestita (Bimeria), 22, 139.
Victorella, 189, ~194~.
Victorellidæ, 191.
Victorellides, 191.
viridis (Hydra), 147.
_vitrea_ (_Hyalinella_), 228.
_vitrea_ (_Plumatella_), 227, 228.
vulgaris (Hydra), 4, 8, 9, 10, 22, 130, 146, ~148~, 149, 158.
whiteleggei (Cordylophora), 141.
yunnanensis (Euspongilla) (Spongilla), 53.
PLATE I.
SPECIMENS OF _Spongilla_ PRESERVED IN SPIRIT.
Figs. 1-3. _S. (Euspongilla) alba_ var. _bengalensis_ (nat.
size) from ponds of brackish water at Port Canning in the
delta of the Ganges. Fig. 1 represents the type-specimen of
the variety, and was taken in the winter of 1905-6. Figs. 2
and 3 represent specimens taken in the same ponds in the
winters of 1907 and 1908 respectively.
Fig. 4. _Spongilla_ sp. (? abnormal form of _S. (Eunapius
carteri_)) from an aquarium in Calcutta (× 10).
[Illustration: Freshwater Sponges. Plate I.
A. C. Chowdhary, del. SPONGILLA.]
PLATE II.
PHOTOGRAPHS OF DRIED SPECIMENS OF _Spongilla_, _Tubella_, AND
_Corvospongilla_.
Fig. 1. Part of a large specimen of _S. (Eunapius) carteri_
from Calcutta, to show the conspicuous rounded oscula
(reduced).
Fig. 2. Gemmules of _S. (Stratospongilla) bombayensis_ on a
stone from the edge of Igatpuri Lake, Bombay Presidency
(nat. size).
Fig. 3. Part of one of the type-specimens of _S.
(Stratospongilla) ultima_ from Cape Comorin, Travancore, to
show the star-shaped oscula (slightly enlarged).
Fig. 4. Part of the type specimen of _T. vesparioides_
(external membrane destroyed), to show the reticulate
skeleton and the numerous gemmules (nat. size).
Fig. 5. Part of a schizotype of _C. burmanica_ to show the
elevated oscula (nat. size).
[Illustration: Freshwater Sponges. Plate II.
Photo by A. Chowdhary. Spongilla, Tubella, Corvospongilla.]
PLATE III.
PHOTOGRAPHS OF SPECIMENS OF _Plumatella_, _Lophopodella_, AND
_Pectinatella_.
Fig. 1. Specimen in spirit of _P. fruticosa_ (typical
form) on the leaf of a bulrush from a pond in the Calcutta
Zoological Gardens (nat. size).
Fig. 2. A small zoarium of the _benedeni_ phase of _P.
emarginata_ from Rangoon (nat. size). Part of the mass has
been removed at one end to show the structure. The specimen
was preserved in spirit.
Fig. 3. Part of a large zoarium of _P. diffusa_ on a log
of wood from Gangtok, Sikhim (nat. size). An enlarged figure
of another part of the same specimen is given in fig. 2, Pl.
IV. The specimen was preserved in spirit.
Figs. 4, 4 _a_. Specimens of _L. carteri_ from Igatpuri
Lake, Bombay, preserved in formalin. Fig. 4 represents a
mass of polyparia surrounded by a green gelatinous alga on
the stem of a water-plant; fig. 4_a_ an isolated polyparium
with the polypides fully expanded from the under surface of
a stone in the same lake. Both figures are of natural size.
Fig. 5. Part of a compound colony of _P. burmanica_ on
the stem of a reed from the Sur Lake, Orissa (nat. size,
preserved in formalin).
[Illustration: Phylactolaematous Polyzoa. Plate III.
Photo by A. Chowdhary. Plumatella, Lophopodella, Pectinatella.]
PLATE IV.
SPECIMENS OF _Plumatella_.
Fig. 1. Vertical branch of a polyparium of _P. emarginata_
from Calcutta, to show method of branching (× 8). The
specimen was preserved in formalin, stained with hæmalum,
and after dehydration and clearing, mounted in canada
balsam.
Fig. 1 _a._ Part of a young, horizontal zoarium of _P.
emarginata_ from Rangoon (× 4, preserved in spirit).
Fig. 2. Part of a zoarium of _P. diffusa_ from Gangtok,
Sikhim (× 4). See Pl. III, fig. 3.
Figs. 3, 3 _a._ Specimens in spirit of _P. allmani_ from
Bhim Tal (lake), W. Himalayas. Fig. 3 represents a mature
polyparium; fig. 3 _a_ a young polyparium to which the
valves of the statoblast (×) whence it had arisen are still
attached.
Fig. 4. Part of a zoarium of the _coralloides_ phase of _P.
fruticosa_ (from Calcutta) preserved in spirit, as seen on
the surface of the sponge in which it is embedded (× 3).
Fig. 5. Part of the margin of a living polyparium of _P.
punctata_ from Calcutta (× 8) with the polypides fully
expanded.
[Illustration: Phylactolaematous Polyzoa. Plate IV.
A. C. Chowdhary, del. PLUMATELLA.]
PLATE V.
SPECIMENS OF _Plumatella_, _Stolella_, AND _Pectinatella_.
Fig. 1. Part of a zoarium of the _coralloides_ phase of _P.
fruticosa_ (× 10) from Calcutta. The specimen, which was
preserved in spirit, had been removed from a sponge of
_Spongilla carteri_.
Fig. 2. Terminal branch of a polyparium of _P. punctata_
from Calcutta (× 30). The specimen was preserved in
formalin, stained with hæmatoxylin, and finally mounted in
canada balsam.
Fig. 3. Part of an adult polyparium of _S. indica_ from
the United Provinces (× 30). The specimen was preserved in
formalin, stained with hæmalum, and finally mounted in
canada balsam. The lower zooecium contains a mature free
statoblast, the upper one a fixed one.
Fig. 4. The growing point of a young polyparium of the
same species from Calcutta (× 30), to show the method of
formation of the stolon that connects the different groups
of zooecia. The specimen had been treated in the same way as
that represented in fig. 3.
Figs. 5, 5 _a_. Zoaria from a compound colony of _P.
burmanica_ from the Sur Lake, Orissa (× 2). The specimens,
which were preserved in formalin, are represented as seen
from the adherent surface of the colony.
[Illustration: Phylactolaematous Polyzoa. Plate V.
A. C. Chowdhary, del. Plumatella, Stolella, Pectinatella.]
* * * * *
Transcriber's note:
In the Systematic Index, sub-family items were renumbered from 15.
through 38., to correspond to the numbers used in the text of the
book.
Greek letters used as symbols are spelled out, e.g. alpha, beta, etc.
Letters missing or mis-typeset were inserted, e.g. 'practica ly' to
'practically'
Footnotes were moved after the paragraph to which they pertain.
Raised dots were replaced with decimal points in numeric notations.
Bold page numbers in the index are surrounded by tildes, e.g. ~76~.
Punctuation was standardized.
Added a description of a sketch contained within one line of text.
Other changes:
'recognzied' to 'recognized' ... be recognized....
'benegalensis' to 'bengalensis' ... lacustris var. bengalensis,...
'pecular' to 'peculiar' ... the peculiar amphipod ...
'milar' to 'similar' ... similar in the two ...
'large' to 'larger' ... a little larger than the upper ...
'pennsylvania' to 'pennsylvanica' ...Tubella pennsylvanica...
'variely' to 'variety' ... specimens of the variety ...
'measurments' to 'measurements' ... the average measurements ...
'It' to 'Its' ... Its buds, however, possessed ...
'dispsition' to 'disposition' ... 'Y-shaped disposition of ...
'Wood's Holl' to 'Wood's Hole' ... Biol. Bull. Wood's Hole,...
'1852' to '1851' at the end of the citation of Leidy's paper, to
match date at the beginning of the citation paragraph.
'syoecium' to 'synoecium' ...in a gelatinous synoecium...
'Lacustre' to lower case ...Ann. Biol. lacustre,...
'Dactyloccopsis' to 'Dactylococcopsis' ... Dactylococcopsis
pectinatellophila ...
'amphioxus' to 'amphioxous' ... amphistrongylous or amphioxous ...
'Trìda' and 'Trida' to 'Trída' for consistency ... Praze, Trída ...