_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.
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account