1921.] B. Prashad : Notes on Lamellibranchs. 145 



as regards proportionate measurements, but in the large series 

 before me intermediate forms connecting the different types from 

 the different localities are present, and I have found it impossible 

 to detect any constant differences between them. A few notes on 

 the form of the young shells may be included here. The young 

 shells are nearly subtrigonal with the posterior margin regularly 

 arched the truncate distal half being not distinctly marked as yet, 

 the umbones are placed more symmetrically and the hinge is of a 

 more normal type. 



Distribution. — C. galathcae had hitherto been recorded from 

 the Galatea River in the Nicobar Islands ; in the collections of the 

 Indian Museum it is represented by a large series of specimens 

 from the Nicobars (Kar Nicobar, Kondal and Trinkat Islands in 

 the Nicobar group) and Andaman Islands (John Lawrence and 

 Havelock Islands in the Andaman group). The species, therefore, 

 has a wide range in the Andaman and Nicobar Islands. 



Remarks. — A few specimens of this species in the collection 

 were found labelled C. patima, Benson, which is apparently a 

 manuscript name only as I have been unable to find any reference 

 to it in literature except in Theobald's catalogue ' 



The shells of this species are of a very characteristic type 

 and are easily distinguished by the greatly inequilateral, greatly 

 vaulted shells with a highly truncate distal half of the posterior 

 margin, anteriorlj' placed umbones and the curved and forwardly 

 placed hinge with very compact but strong laterals. 



5. Indian Species of the Genus Batissa. 



Up till recently the only known species of the genus Batissa, 

 Gray, from within the limits of India, Burma and Ceylon were B. 

 similis and B inHata described by Prime from the Nicobar Is- 

 lands in 1859^ and iS6o ' respectively. In 1908* Preston des- 

 cribed a unique specimen from the Andaman Islands, collected by 

 the late Rev. J. Warneford, under the name B. capillata. In the 

 Indian Museum collection I found two boxes of specimens from 

 the Andaman Islands provisionally labelled B. violacca, Brug., by 

 the late Mr. G. Nevill ; in addition there were a fair number of 

 specimens from the Andaman Islands which had not been identi- 

 fied. Through the courtesy of Professor Max Weber I received a 

 specimen of B. violacea var. celebcnsis. Martens,* collected by 

 Prof. M. Weber in the Celebes and identified by the late Dr. E. von 

 Martens. The specimen is preserved in spirit and is in an excellent 

 state of preservation. With this material I have drawn up the 

 following notes on the collection in the Indian Museum including 

 a detailed description of the soft parts of the genus Batissa 



' Theobald, Cat. Rec. Shells. Mus. .-Is. Soc. Bengal, p. 140 (Calcutta, i860). 

 ' Prime, Ann. Lyceum Nat. Hist. Soc. New York VII, p. 112 (1859). 

 ■' Id., Proc. Zool. Soc. London XNVIII, p. ,520 (i860). 

 * Preston, /?ec. Ind. Mus. II, p. 207, pi. xvi, fig. 39 (1908). 

 ^ Von Martens, Siiss. ttnd Brack-v.-Moll. in Zool. Ergeb. Nieder. Ost. Ind. 

 IV, p. ,04 (1897). 



