XVI. NOTEvS ON LAMELIvIBRANCHS IN 

 THE INDIAN MUSEUM. 



By B. Prashad, D.Sc, Offg. Superintendent, Zoological Survey 



of India. 



(Plate XX.) 



4. Indian Species of the genus Cyrena. 



The present revision of the Indian species of the genus 

 Cyrena, Lamarck, might appear superfluous in view of the recent 

 treatment of the subject by Preston in his volume on Mollusca 

 in the " Fauna of British India," but the above work is mainly 

 a compilation from the earlier monographs by Prime,' Clessin '^ 

 and Sowerby.'* It was found on examination of the collections in 

 the Indian Museum that the descriptions of the Indian species in 

 these works were very faulty and inadequate being based on 

 insufficient material and that too, in most cases, consisting of 

 young or half-.;rown shells only. These descriptions, owing to 

 the great changes that usually take place in the shape of the 

 shells during growth, are not applicable to adult shells, and are 

 incomplete so far as the description of the hinge is concerned, 

 while the geographical distribution of the various forms is not 

 correctly given. I have, therefore, thought it desirable to re- 

 describe some of the species and in other cases to point out the 

 distinguishing characters. 



According to Preston the following species occurs within the 

 lim.ts of British India, Burma and Ceylon, C. ceylonica, C. im- 

 pressa, C. stnuosa, C. bengalensis, C. tcnncntii, C. proxim.i and C. 

 galathcac. Of these species C. sinuosa, Deshayes, was included in 

 the list on Sowerby's authority. The species is known from Java 

 and except for Sowerby no other author has recorded its occur- 

 rence in Ceylon. In the Indian Museum collection there are large 

 collections from various parts of Ceylon, but none of these speci- 

 mens are referrable to Deshayes' C. sinuosa, and I am very doubt- 

 ful whether Sowerby's record can be accepted as correct. Sowerby 

 probably confused some specimens of the nearly allied C. ceylonica 

 with those of Deshayes' species or the localities on his specimens 

 must have been incorrectly stated. With the above exception I 

 have found Preston's list to be quite correct, but I have also to 



' Prime, Cat. Corbiculidae in Amer. 'Journ. Conch. V (l86g — 1870), and 

 other papers cited further on. 



- Clessin, Cycladeen in Martini and Chemnitz Conch.-Cab. (1879). 

 •■> Sowerby, Conch. Icon. XX (1878), 



