222 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



muscle (whicli is much longer than that of S. Dombeyi, but shorter 

 than that of either T. rufus or T. gilbus), and, as far as I have been 

 able to ascertain from the specimens submitted to me for examination, 

 in the possession of elevator pedis and protractor pedis muscles. 



Pallial Muscles. — The muscles of the mantle-lobes (Fioj. 4, M.L.) 

 begin at the anterior end as a deep band, and lessen in depth as 

 they proceed posteriorly. 



The anterior adductor muscle (Fig. 4, A. A.), which lies inclined 

 a little in an antero-ventral position, is a broad and deep muscle, 

 curved dorsally, and gradually decreasing in depth towards the 

 posterior side. It is connected anteriorly with the mantle-lobes and 

 posteriorly with the proximal portion of the foot and body-covering. 

 I cannot trace any complete division of it by the ventral integument 

 passing between the anterior and posterior portions. 



The posterior adductor muscle (Fig. 4, P. A.) is very deep, but 

 shallows somewhat towards the posterior side. It is connected 

 anteriorly with the body-covering and the posterior retractor pedis 

 muscle, and posteriorly with the mantle-lobes. 



The musculus cruciformis (Fig. 4, M. C.) is a broad transverse muscle 

 situated ventrally to the posterior adductor muscle, near to the edge of 

 the mantle-lobe. It appears to be in one piece, of nearly the same 

 width and depth throughout, with its external surfaces adhering to 

 the valves of the shell. There is a slight indication of the presence of 

 the branchial muscles (Fig. 4, B.R.), which are attached to the shell 

 a little behind the pedis elevator muscles. 



Pedal Muscles. — As before stated, the muscles of the foot are very 

 muscular, the muscularity reaching as far as the dorsal surface of the 

 proximal portion of it. 



The protractor pedis muscles (Fig. 4, P.P.) are short and situated 

 posterior to, with the terminal parts a little over, the anterior adductor 

 muscle. 



The retractor pedis anterior muscles (Fig. 4, P.R.A.) are likewise 

 short, and situated a little distance posterior to the protractor pedis 

 muscles. 



The elevator pedis muscles (Fig. 4, E.P.) are posterior, though nearer 

 the median line, to the retractor pedis anterior muscles. 



The retractor pedis posterior muscle (Fig. 4, P.R P.) is a rounded 

 muscle of medium length, with the distal end of it bifurcated, the 

 bifurcations resting on the antero-dorsal edge of the posterior adductor 

 muscle. 



Alimentary Canal. — The lips (Figs. 4, 5, and 6, A.L. and P.L.) 

 point antero-ventrally. The oesophagus (Figs. 5 and 6, A.L. and 

 P.L.), which is of medium length, soon expands into the oesophageal 

 division of the stomach (Figs. 5 and 6, Oe.St.). This division widens 

 out posteriorly as far as what I have previously termed the muscular 

 papilla (Fig. 5, M.P.). The anterior continuation of the latter projects 

 laterally some considerable distance across the stomach, separating the 

 cardiac (Fig. 5, C.St.) from the central (Fig. 5, CD.) division, but 

 both of these divisions are small. The pyloric division (Figs. 5 and 6, 

 P.St.) is large, and continues as the caecum of the crystalline style 



