IQTQ.] N. Annandai:.e& B. Prashad : Gangetic Delta Molluscs. 249 



We have compared Nevill's types with Preston's, and can 

 find no difference. The species appears to be very variable and 

 the varieties described, or rather named, by Nevill in his Hand- 

 list are possibly mere individual variations. The var. minor, 

 however, may be worthy of varietal nomenclature. 



The species is very common among weeds in pools of brack- 

 ish water at Port Canninof. 



Family ASSIMINEIDAE. 

 Genus Assiminea, Leach. 



1S87. Assiminea, Bottger, '^aJirb. deutsch. Malalakozool. Ges., XIV, p. 



158. 

 1880? Assiminea, Heude, "Moll. Terr. Mem. Hist. Nat. Chin.," l,p, 82. 

 1897. Assiminea, von Martens in Weber's Zool, Ergeben. Neiderl. Ost.- 



Ind., IV, p. 212. 



Bottger in his monograph of the genus arranges the species 

 alphabetically , among the Chinese forms Heude recognizes three 





Text-fig. 4. — Radular teeth of Gangelic species of Assiminea. 



(a) A. brevicula (Pfr.). (b) A. beddomiana, Nevill. 



(c) A. francesiae (Gray). 



divisions, which he calls Euassimineae, Pseudomphalae and 

 Salenomphalae; while von Martens, discussing the species of the 

 Malay Archipelago, divides the genus into two groups, Cyclotrophis 

 and Assiminea, s.s., which is distinguished from Cyclotrophis by 

 the presence of a sharp rim at the inner edge of the umbilicus of 

 the shell. We have here to consider three species, two of which 

 [.4. brevicula {Vir.) and A. beddomiana, Nevill] belong to Assiminea, 

 s.s., while the third [A. francesiae (Gray) J perhaps represents 

 Cyclotrophis but ma}' ultimately call for generic distinction. 



