bloomer: anatomy of ENSIS (sOLEn) MAGNUS, SCHUMACHER. 77 



on the inside edge of the mantle lobes. Around the inside of it, but near 

 the outer edge, is a row of tentacles ; those on one side alternating with 

 those on the opposite side (the tentacles are not so long as in E. p^n/x.) 



On the inside of each mantle k)be is a groove passing dorsally from this 

 aperture towards the foot, and in it lie the distal portions of the labial 

 palps. 



The anterior adductor muscle is an extremely broad and shallow muscle, 

 deepening as it proceeds posteriorly. It is connected anteriorly with the 

 mantle lobes and dorsal integument, and posteriorly with the dorsal and 

 ventral integuments. 



The posterior adductor muscle is a comparatively small muscle, curved 

 ventrally and flattened dorsally. It is joined anteriorly with the bifurca- 

 tions of the retractor pedis posterior muscle, and posteriorly with the dorsal 

 integument. 



The retractor pedis anterior muscles, as in E. ensis, have long bifurca- 

 tions, the posterior ones passing through the liver to the valves of the shell, 

 and the anterior ones going some distance over the anterior adductor muscle 

 before adhering to the shell. 



The retractor pedis posterior muscle is a thick muscle of medium 

 length, the bifurcations of it, which are attached to the shell, rest against 

 and are connected with the posterior adductor muscle. 



Owing to the imperfect preservation of the inside of the animal it is 

 not possible to make out the internal structure in detail, but it appeared to 

 be very similar to E. en$ii<. 



The gills are of the type heterorhabdic and are also plicate, but the 

 plication is shallower than in E. e«.siV, while the interlamellar junctions are 

 longer. The number of filaments in a plica range between 13 — 17. 



