This genus has the characters of the family. Its status has been much
disputed, some authors regarding the shape of the lophophore as of great
morphological importance, while Jullien believed that _Fredericella_ was
merely an abnormal or monstrous form of _Plumatella_. The latter belief
was doubtless due to the fact that the zoaria of the two genera bear a
very close external resemblance to one another and are sometimes found
entangled together. The importance of the shape of the lophophore may,
however, easily be exaggerated, for, as both Jullien and Goddard have
pointed out, it assumes an emarginate form when retracted.
The best known species is the European and N. American _F. sultana_
(Blumenbach), of which several varieties or phases have been described
as distinct. This form is stated to occur also in S. Africa. _F.
australiensis_, Goddard[BC] from N. S. Wales is said to differ from this
species in having an oval instead of a circular lophophore and in other
small anatomical characters; but it is doubtful how far these characters
are valid, for the lophophore appears to be capable of changing its
shape to some slight extent and has been stated by Jullien to be
habitually oval in specimens from France. _F. cunningtoni_,
Rousselet[BD] from Lake Tanganyika has stout zooecia encrusted with
relatively large sand-grains.
[Footnote BC: Proc. Linn. Soc. N. S. Wales, xxxiv, p. 489
(1909).]
[Footnote BD: Rousselet, Proc. Zool. Soc. London, 1907 (1),
p. 254.]
The zoaria of _Fredericella_ are usually found attached to solid objects
in shallow water, but a form described as _F. duplessisi_, Ford has been
found at a depth of 40 fathoms embedded in mud at the bottom of the Lake
of Geneva. _F. cunningtoni_ was dredged from depths of about 10 and
about 25 fathoms.
The statoblasts of this genus do not float and often germinate in the
parent zooecium after its polypides have died. They are produced in
smaller numbers than is usually the case in other genera of the order.
The polypides sometimes undergo a process of regeneration, but without
the formation of brown bodies.
[Illustration: Fig. 41.--_Fredericella indica._
A=statoblast, × 120. B=outline of expanded lophophore and adjacent
parts, × 75; a=anus, r=rectum. C=outline of zoarium on leaf of
water-plant, × 3.
(A and B are from specimens from Igatpuri, C from specimen from
Shasthancottah).]
28. Fredericella indica, _Annandale_.
_Fredericella indica_, Annandale, Rec. Ind. Mus. iii, p. 373,
fig. (1909).
_Fredericella indica_, _id._, _ibid._ v, p. 39 (1910).
_Zoarium._ The zoarium is of delicate appearance and branches sparingly.
It is often entirely recumbent but sometimes produces short, lax
branches that consist of two or three zooecia only.
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