36 Memoirs of the Indian Museum. [Voi,. V, 



carnosus (Johnston)/ S. inconstans, Pendy 2 and S. cruciatus of the same author. 3 

 The first of these is a cosmopolitan species found by Carter in the late Dr. J. 

 Anderson's collection from the Mergui Archipelago: the two latter were described by 

 Prof. Dendy from Mr. E. Thurston's and Prof. Herdman's collections from the Gulf 

 of Manaar. Thiele + states that S. inconstans is a Spirastrella, but I have not 

 succeeded in finding the characteristic microscleres of that genus in specimens from 

 the Gulf of Manaar; possibly the sponges from Celebes examined by Thiele repre- 

 sented a distinct species. Carter's Suberites vestigium, 5 an example of which was 

 recently obtained by Mr. S. W. Kemp at Kilakarai on the Gulf of Manaar, is a Pseudo- 

 sub erit es. 



One species of Suberites (s.s) is well represented in our collection of the Chilka 

 fauna, namely 5. sericeus, Thiele, a very distinct form that shows a relationship in 

 one of its phases to Pseudosuberites, though better developed sponges clearly belong 

 to the parent-genus of the family. This species was originally described from Japan. 



Suberites sericeus, Thiele. 



(Plate iv, fig. 4.) 



1898. Suberites sericeus, Thiele, Stud. ii. pacif. Spongien (Bibl. Zool. X, 24), 

 p. 39, pi. viii, fig. 10. 



Thiele' s species was described from two small specimens that had grown on the 

 shells of Gastropods. Apart from his account of the spicules, of which he gave a 

 good figure, the description was by no means full and all that we learn from it is that 

 the specimens, which were dry, formed thin films of small size and that the skeleton 

 of one was amorphous while that of the other was " somewhat reticulate." Fortu- 

 nately the spicules are characteristic. Although all are macroscleres and tylostyles, 

 they may be separated into two classes, the more distinctive of which is remarkable 

 for its short, stout form (fig. 5). 



In the Chilka Lake this sponge is found in two phases, one -of which is appa- 

 rently identical with that of the type- specimens, while the other is much more 

 robust. The former may be called phase A, the latter phase B. 



In phase A the sponge is restricted in area, forms a film not more than 2 mm. 

 thick and has a minutely hispid but otherwise smooth surface ; whereas in phase B 

 it extends over areas of considerable extent, may attain a depth of at least 50 mm., 

 and is not only hispid on the surface but also produces irregular projections and, 

 occasionally, curious ear-like horizontal outgrowths. 



The two phases are not absolutely distinct, for the extreme periphery of large 

 masses of sponge closely resemble phase A and when masses of the kind grow out 



1 Most fully described by Topsent in the paper cited (1900), p. 233. 



2 Ann. Mag. Nat. Hist. (5) XX, p. 154, pis. ix, x (1887). 



3 In Herdman's Ceylon Pearl Fisheries III, p. 131, pi. v, fig. 10. 



* Stud. ii. Pacifisch. Spongien (Bibl. Zool. X, 24), p. 10, pi. i, figs. 3-, 3«, pi. v, fig. 4 (1899). 

 5 Ann. Mag. Nat. Hist. (5) VI, p. 52, pi. v, fig. 21 (1880). 



