8 PUOCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



attaclied to the shell. The siphonal tubes (Fig. 2, Ex.S.', In.S.') are 

 also muscular and externally are transversely ribbed, whilst internally 

 they present evidences of slight longitudinal ribbing. 



Pedal Muscles. — The retractor pedis anterior muscles are inserted 

 into the shell ou the dorsal surface. 



The protractor pedis anterior muscles are attached to the shell and 

 to the anterior adductor muscle close to the lateral edge. 



The retractor pedis posterior muscle (Fig. 2, P.R.P.) is short and 

 thick, with its bifurcations resting upon the antero-dorsal edge of the 

 posterior adductor muscle. 



The attachment to the shell of the pedis elevator and branchial 

 retractor muscles cannot be traced with certainty. 



Alimentary Canal. — The mouth (Fig. 2, M.) is wide with the lips 

 lying in an anterior direction. The oesophagus passes with a curve to 

 the stomach (Fig. 2, St.) ; the latter is long, but internally its shape 

 is not plainly discernible. It appears to be divided into three parts, 

 the oesophageal and cai'diac ones being long and shallow, and separated 

 from each other, on the left side, by a lateral process of the gastric 

 wall, whilst the pyloric division is much larger, and on the ventral 

 surface is continued as the caecum of the crystalline style (Fig. 2, C.C.) 

 which extends to near the ventral part of the foot. The intestine 

 (Fig. 2, In.) has the aspect of being only a groove on the left side of 

 the caecum, but becomes quite separate at the distal end of the caecnm, 

 where it turns rearwardly, and passes dorsally to near the posterior 

 part of the stomach ; there it makes a number of folds and goes 

 posteriorly, as the rectum, over the posterior adductor muscle to the 

 anus (Fig. 2, A.), situated at the postero- ventral edge of the latter 

 muscle. 



It is not possible to make out the nervous system except the position 

 of the viscero-parietal ganglia, situated at the antero-ventral edge of 

 the posterior adductor muscle. 



SoLECCUTUs (Azor) coaectatus (Gmel.).^ 



The specimen described from Japan in 15 fathoms differs con- 

 siderably from A. antiquatus from the Fnglish Channel. 



The Japanese shell, measured antero-posteriorly, is shorter than the 

 English species, the difference being chiefly in the part posterior to 

 the umbonal region, whilst the posterior edge is a little more angular. 

 Measured dorso-ventrally it is deeper than the English species. From 

 the umbonal region of both specimens, and passing in a slightly 

 postero- ventral direction, is on each side a constriction of the shell. 

 This is, however, more pronounced in A. coarcfatiis. 



The animal itself is in a far better state of preservation than the 

 one previously described, thoujrh more contracted. The muscles of 

 the mantle border are well developed and much deeper at the anterior 

 part. The chief difference, however, is in the proximal portion of 

 the siphon, which is very prolonged in the English species, but the 



^ See Smith, Challenger LameUibrandiiaia, 1885, p. 79. 



