POLYZOA. 



By N. Annandale. 



Eight species of Polyzoa have been found in brackish water on the coasts of 

 India, but of these only three occur, so far as we know, in the Chilka Lake. A 

 fourth was abundant some years ago in small pools of brackish water near its 

 inner shore, but has now disappeared and has not been taken in the lake itself. 



A list of the eight species will be found in the Table of Contents on the opposite 

 page. One half of these species are apparently endemic in estuarine tracts, maritime 

 swamps and lagoons in India, while the other half are cosmopolitan or at any rate 

 very widely distributed. The two series may be tabulated thus: — 



Endemic Indian Species. Wideey Distributed Species. 

 Membranipora bengalensis , Membranipora hippopus, 



Victorella bengalensis , Bowerbankia caudata, 



Loxosomatoides colonialis, Alcyonidium mytili, 



Loxosomatoides laevis. Barentsia discreta. 



With one exception the genera are cosmopolitan. The exception is Loxosoma- 

 toides, which is only known from estuarine tracts and lagoons on the east coast of 

 India. The two species of this genus, as well as the two other endemic forms in the 

 list, have been found only in water of slight or variable salinity, while all the 

 cosmopolitan species are known to occur in the sea. Loxosomatoides is closely related 

 to the North American freshwater genus Urnatella. 



The species found in the Chilka Lake are Loxosomatoides laevis, Membranipora 

 hippopus and Alcyonidium mytili, while the one that formerly occurred in pools in 

 the vicinity was Bowerbankia caudata. The first three of these are abundant or at 

 least fairly common in both divisions of the lake, among the permanent inhabitants 

 of which they must all be included. L. laevis also occurs in lagoons near Madras 

 and is closely related to the Gangetic L. colonialis. The absence of Victorella and 

 of M. bengalensis is rather strange, for both forms occur almost certainly at Bombay, 

 while the Ctenostome has also been found at Madras. Both are very abundant 

 where they do occur, and neither could well escape the notice of a collector accus- 

 tomed to look for it. Possibly their absence is due to lack of suitable food. 



The only important biological fact I have to add to our knowledge of these 

 brackish-water Polyzoa is that Loxosomatoides produces resting buds. The struc- 

 ture of these buds is discussed on p. 130. 



In addition to the indigenous Polyzoa of the lake we found within its boundaries 

 specimens of two other species a marine Cheilostome and a freshwater Phyla ctolae- 



