1921.] Manipur Molluscs. 615 



b. Shell climgate-ovate, ratlier thick and op.iquc, with 

 the timbones more prominent than in i', indiciim, 

 but mucli less so than in S. avannni ; sculpture 

 better marUod than in .*v'. iiidiciim ... ... S. niisteiii. 



Sphaerium indicum, Deshaj'es. 



1854. Spliaeriiim indicum, Deshayes, Proc. Zoo! . Sor. London XX 11' 



P- 34-;- 

 igij. Sphaerium indicum, Preston, op. cif.. p. 224. 



Preston is certainly mistaken in assigning this species to A. 

 Adams and in considering Deshayes' name as a manuscript name 

 only, for the reference to the original description of the species 

 cited above and noted by Preston is a paper by Deshayes on new 

 species of shells in Cumming's collection, and not by A. Adams as 

 Preston states. A paper by A. Adams is published immediately 

 preceding that of Deshayes and Preston apparently confused 

 them when citing the references. 



F ~ 



I.e. 



Fig. 34. — Soft parts of Spliaerium indicum. 

 F. foot ; l.G. inner gill ; O.G. outer gill ; M. mantle : P. palp ; i^ siphons. 



The hinge of this species differs from that of my new species, 

 described further on, in the laterals being much better developed 

 and less curved and in there being a single well-developed cardinal 

 in the right valve, the second cardinal of this valve is much reduced 

 or even abseirt in some specimens. 



The soft parts of this species are described in detail below as 

 no account of the anatomy of Indian species has been published 

 before 



The animal conforms in shape to that of the shell and is of a 

 whitish colour. Of the adductor muscles, the anterior is rather 

 small and rounded while the posteriir is much larger and somewhat 

 quadrangular in outline. The posterior retractor pedals are well 

 developed and lie above the posterior adductors. The pallial 

 muscles consist of radiating muscle-fibres starting from just 

 below the pallial attachment and are continued in the inwardly 

 reflected region of the mantle. No siphonal retractors can be 

 distinguished from the pallial fibres. 



