igi6.] Fauna of the Chilka Lake : Mollusca Gastropoda, etc. 347 



hermit-crab improbable and we may suppose that the species is a marine one that 

 occasionally enters the channel in the salt-water season. 



Family Pyramidellidae. 



Pyrgulina humilis (Preston), Joum. Malacol., XII, p. 6, pi. ii, fig. 27; 1905 [as 

 Pyramidella (Mormula)]; 1915, p. 294 [as Chrysallida (Mormula)]; 1916, p. 32. 



P. humilis, with its variety chilkaënsis, Preston (loc. cit. 1915) was found in 

 large numbers in the outer channel at all times of the year. A few specimens were 

 also taken S. of Kalidai and off Nalbano. The variety appears to be more common, 

 at any rate in July, than the typical form. 



Chrysallida (Mormula) ecclesia* Preston, 1915, p 295, figs. 7, y a. 

 A single living specimen was taken in Madarchua Bay at the south end of the lake 

 in July. 



Chrysallida (Mormula) nadiensis * Preston, 1915, p. 296, figs. 8, 8a. 



This species was only found in the outer channel in the freshwater season; it is, 

 however, very scarce and probably occurs at all times of the year in this part of the 

 lake. 



Odostomia chilkaënsis ,* Preston, 1914, p. 301, fig. 4; 1915, p. 296. 



Only two specimens were obtained, both in the outer channel, one at Manik- 

 patna in March and one near Mahosa in September ; the latter, however, was a dead 



shell. 



Family Neritidac. 

 Neritina (Theodoxus) souverbiana, Montrouzier, Montr, and Souverb., Joum. 



Conch. (Paris), XI, pp. 75, 175, pi. v, fig. 5 (1863). 

 Specimens were found in the outer channel both in March and in September ; 

 they were common near Mahosa in the freshwater season, living among weeds. The 

 species, which was described from the China Sea and New Caledonia, is apparently 

 a marine one that in the sea lives among algae. 



Family Cyclostrematidae. 



Cyclostrema (Tubiola) innocens* Preston, 1915, p. 296, figs. 9, ga, gb. 

 A single dead shell (the type of the species) was obtained in Seruanaddi in the 

 freshwater season. 



[The shell described by G. Nevill ' as Valvata ? microscopica, of which we have 

 examined a long series of co-types, clearly be- 

 longs to the same genus as C. innocens. It 

 appears to differ from that species only in its 

 smaller size, reddish colour and in the sculp- 

 ture on its surface ; but the type of Preston's 



species is bleached and perhaps somewhat _ „ , . .. '. T .„, 



r r r p IG _ 2. — Cyclostrema microscopica (Nevill). 



eroded. We figure (fig. 3) one of the co-types 

 of Nevill's species.] 



1 Cat. Moll. Ind. Mus., fasc. e, p. 21 (1877). 



