52 Records of the Indian Museum. [Voi,. XIX, 



1887. Soloi, Fischer, Ma?i. de Conch., p. mo. 



1889. Solen (pars), Clessin in Martini-Chemnitz, Svsi. Condi. -Cab., 

 XI {Solanacea), p. 2. 



The original genus Solen, Linne, has been split up by Schu- 

 macher (45) into three, viz., Solen, Ensis and Cultellus, the distinc- 

 tion of which has been confirmed by the anatomical researches of 

 Bloomer (8, pp. 43-45). He described and compared a large 

 number of species of Solen in a series of papers. I have three 

 species of Solen at my disposal, viz., S.kempi, Preston, 5. sp. 

 from Japan and another species which appears to be new (5. gravelyi, 

 sp. n.), the anatomy of which I have been able to study. 



The following diagnosis has been drawn up from the work of 

 Bloomer as well as from my study of the above species : — 



Animal. Body elongated, and narrow ; dorsal and ventral 

 margins very nearly parallel to each other ; anterior and posterior 

 margins straight and sloping. Pedal aperture generally confined 

 to the anterior margin, sometimes extending posteriorly. No 

 fourth aperture. Siphon a single piece with the distal end fringed 

 with tentacles. Anterior adductor muscle narrow and elongated. 

 Posterior adductor muscle oval. Foot cylindrical, somewhat 

 flattened laterally with the anterior end more or less dilated. 

 Radiating fibres of the retractor pedis anterior muscle passing 

 outside the longitudinal muscle of foot. Labial palps elongated 

 and narrow ending in a point generally. Anterior Hp of the mouth 

 separated from the posterior end of the anterior adductor muscle 

 by a distinct interval. Gills narrow and elongated, prolonged into 

 the proximal end of the branchial siphonal canal ; plicate and 

 heterorhabdic, the plicae being free from one another. Visceral 

 portion of the gills forming less than half their entire lengths. 

 Inner lamella of the inner gill free in the visceral portion, but 

 united with its fellow of the opposite side behind (except in 5. 

 gravelyi, sp. n.). Coecum arising from the ventral aspect of 

 pylorus and passing forward. Intestine generally of Solen subtype 

 (p. 50). Heart generally placed in the middle of the pericardial 

 chamber. Liver not extending anteriorly over the anterior 

 adductor muscle. A single anterior pallial nerve from each cerebro- 

 pleural ganglion. Viscero-parietal ganglia placed beneath the 

 bifurcation of the retractor pedis posterior muscle. A single 

 circumpallial nerve. 



Solen kempi, Preston. 



1915. Solen kempt, Preston, J^ec. Ind. Mus. XI, p. 305, figs. 18, \Sa. 



1916. Solen ketnpi, Annandale and Kemp, Mem. Ind. Mus. \ . p. 355. 

 1916. Solen annandalei, id., ibid., pi. xvi, fig. 8.' 



Animal (pi. II, figs. 1-5). The body is five times longer than 

 broad, being deepest somewhat behind the anterior end. The 

 anterior margin is curved above and straight below. The posterior 



1 Dr. Annandale informs me that the figures on the plate have been accident- 

 ally transposed owing to incorrect labels received from the author of the soecies. 



