60 •Contributions to Indian Malacology. [No. 1. 



No. 16, Neritina obtusa, Benson. 



Scarce. I obtained two specimens on limestone rock at Thaman- 

 dewa in the Bassein river. 

 No. 17, Neritina Smithii Gray. 



Less common than in the estuary of the Granges. 



I have another species of Neritina belonging to the typical section 

 from the estuary of a small stream running into the sea just north of 

 Cape Negrais. I have been unable to identify it with any known 

 species, and it may possibly be new.* 

 No. 18, Neritina (Dostia) depressa, Benson, pi. I, fig. 17,18, 19. 



There are specimens of this shell amongst my Irawaddy collections : 

 I think they are from Rangoon. The species is generally found in 

 fresh or slightly brackish water, while Neritina crepidularia and N. 

 cornucopia are chiefly met with nearer the sea, where the water is 

 more salt. In Bombay Island, however, I have met with N. depressa 

 on the sea shore. 

 No., 19, Neritina (Dostia) crepidularia, Less. PI. I. fig. 20, 21, 22. 



This shell and the next are found rather abundantly upon trees 

 growing in places covered by water at each tide, and especially upon 

 Nipia palms. N. crepidularia frequently occurs upon the sea shore, as 

 well as in estuaries. 

 No. 20, Neritina (Dostia) cornucopia, Benson, pi. I. fig. 23, 24, 25. 



Locally abundant. The shells found by me in Pegu differ slightly 

 from the type, which is scarce in the Hoogly at Calcutta. In the 

 latter, the apex of the shell is very nearly in the same plane as the 

 edge of the peristome, sometimes actually so and touching it. In Pegu 

 specimens, the peristome is free from the apex. The difference is very 

 trifling, and there is slight variation in this character in specimens from 

 the same river. In other respects, the shells appear to agree excel- 

 lently. 



I learned from Mr. Benson some years since that Neritina melano- 

 stoma, Troschel, is identical with N. cornucopia, the latter name having 

 priority.f The figures of the former in Philippi's Abbildungen 



* Further examination shews it to be one of the forms already referred to 

 as intermediate between N. Peguensis and N. retifera, B. It is smooth like the 

 latter. 



f N. melano stoma was published in Wiegman's Archiv for 1837, p. 179 ; 

 N. cornucopia was described by Mr. Benson in this Journal for 1836. 

 Vol. V. p. 748. 



