1920.] B. Ghosh : Anatomy of the Solenidae. 53 



margin is straight. The dorsal margin is shghtly concave in front 

 and slightly convex behind. The siphon is long and segmented, 

 but missing in the specimen as ''it threw it off when captured" 

 (Dr. N. Annandale's note). The surface of the distal end of the 

 branchial siphon presents six small prominences. The pedal aper- 

 ture is confined to the anterior margin and the antero-ventral 

 notch. It is bounded by the pedal valves_, with a small tentacle- 

 like process from the dorsal aspect where the pedal valves meet. 



The foot is long, somewhat flattened, and is shaped like the 

 blade of a scalpel from the side ; it is about half the body in 

 length, and is more thickened in the middle than at either end. 



The anterior adductor muscle is very long, five times as long 

 as deep. The posterior adductor muscle is wide and slightly 

 elongated. 



The labial palps are narrow and greatly elongated, being 

 somewhat wide posteriorly and tapering to a curved point behind. 



The gills are elongated, about five times as long as broad, and 

 more than one-third the bod}' in length. The visceral portion of 

 the gills is very small. 



The oesophagus is fairly long and curved. The stomach has 

 a well developed cardiac and pyloric portion, the latter forming a 

 distinct cul-de-sac beyond the crystallme style. The intestine 

 arising from the anterior end of the pyloric chamber soon forms 

 a number of close coils and then passes round the long coecum 

 forming loose folds in its posterior limb. It forms a round loop 

 before ending in the rectum. The digestive gland surrounds the 

 stomach and the beginning of the intestine. 



The heart is placed in the middle of the pericardial chamber. 



Considering the general structure of the body, the animal is 

 evidently more elongated in its anterior than in its posterior 

 portion, the effect being impressed upon all the organs in that 

 part of the body. 



Solen sp. 



A single specimen was received from the Zoological Survey 

 of India. It was brought by Dr. N. Annandale from Moji, Japan. 



Animal. The body is about five times as long as broad (6*4 

 cm. long), with the posterior end slightly deeper than the anterior. 

 Both the anterior and posterior margins are straight, the anterior 

 sloping forwards. The pedal aperture is confined to the anterior 

 margin. The siphon is ver}^ short and completely retractile inside 

 the shell. The branchial aperture is much wider than the anal, 

 and presents a pair of small valves at its proximal end. A longi- 

 tudinal ridge extends from the ventral aspect of the proximal 

 portion of the branchial siphon to the fused ventral margin of the 

 mantle, with a second smaller one beneath and parallel to it. 



The anterior adductor muscle is elongated, but not so narrow. 

 The posterior adductor muscle is small and oval. The retractor 

 pedis posterior muscle is elongated and larger than the posterior 

 adductor muscle at its insertion. 



