502 Records of the Indian Mnsenm. [Vol. XXII, 



Ostrea gryphoides (Sclilotheim). 



iqi2. Ostrea gryphoides. Newton and Smith. Rec. Geol. Surv. Ind. 

 XII, p. 7, pis. i-vi. 



Newton and Smith have identified the recent species, which 

 occurs very commonly from the Mekran Coast to the Malay Pen- 

 insula, with the miocene 0. gryphoides ; Annandale and Kemp (loc. 

 cii.), on Mr. Vredenberg's authority, consider it doubtful whether 

 the living form should not be known as 0. virginiaua rather than 

 0. gryphoides. As the identity of the Indian and the American 

 species has not yet been definitely established, I prefer to designate 

 the Indian and Sumatran forms 0. gryphoides. The differences in 

 the shell of the American 0. vir°iniana and the Indian species 

 were fully noted by Newton and Smith, and are summarised in the 

 paper b}' Annandale and Kemp. 



The Sumatran shells are closely similar to the Indian forms 

 from the Malay Peninsula and other localities in the Indian Museum 

 collection. They resemble the photographs on pis. iv and v of 

 Newton and Smith's paper. The specimens were collected by Mr. 

 den Doop in the mangrove-swamp region at Belawan (Deli). 

 The shells are not much worn, but are parasitised by some species 

 of boring sponge of the genus Cliona. The external surface 

 of the shell and the inner layer are whitish, the muscle scar is 

 somewhat yellowish, while the ligament has a blackish colour. 



I 



Subgenus Alectryonia, Fischer Waldh. 

 Ostrea folium, Linn. 



1897. Ostrea folium, v. Martens, of), cit.. p. 222. 



Typical specimens of this species are present from the mouth 

 of the Soengei Batang Kwis (Serdang). The specimens were col- 

 lected in the estuarine area and are stated to be subfossil in a 

 sandy incision of an old peniatang. This incision was made for a 

 new drain-canal on the estate. 



Ostrea cuculata, Born. 



1897. Ostrea cuculata, v. Martens, op. cit.. p. 223. 



1916. Ostrea cuculata. Annandale and Kemp Mem. Iiid. Mns. \ . p 

 .^49, pi. xiv, figs. 2. 



This widely distributed species is represented by two partially 

 bleached shells from the same locality as the preceding species. 

 The specimens are rather broken and imperfect. 



Family Unionidae. 



Many species of this family have been recorded from Sumatra 

 by Bruno Strubbel, von Martens and others, but in the present 

 collection this family is poorlj^ represented.' In a recent paper I 



1 I think in the region where I collected this family is very poorly represented. 

 01 this the freshwater Neritinas afford another instance. These are entirel\- 



