8o BLOOMER : ANATOMY OF CERTAIN SPECIES OF SOLENIDAE. 



The pedis retractor posterior muscle (fig. i, P.n.P.) is also sliort and 

 thick. The bifurcations are short too, and rest on the antero-dorsal sur- 

 face of the posterior adductor, where they are connected with the valves of 

 the shell. 



There appears to be some indication of the presence of the branchial 

 retractor muscles as noticed in iS. sfriiji/Iaft/f-; but in the specimens examined 

 they are so indistinct that it is impossible to state definitely whether they 

 exist or not. 



Alimenlary Canal. — The lips (figs. 2 and 3, A.L.Awd P.L.) are broad 

 and not very long. The oesophagus (figs 2 and 3, Oe) is short and soon 

 opens into the oesophageal division of the stomach (figs. 2 and 3, Oe. St.). 

 The latter is large and of irregular shape. Posteriorly it is separated from 

 the cardiac (fig. 2, C. St.) and central (fig. 2, CD.) divisions by a slight 

 muscular ridge. On examining the left side of the stomach (fig. 2) it will 

 be observed that the cardiac division, which is small, lies between the 

 oesophageal and pyloric (figs. 2, P.St.) divisions, and antero-dorsally to the 

 central division. Further the central division is bordered dorsally l>y a 

 more muscular ridge (fig. 2, M.P.), the homologue of the muscular papilla 

 of Solan. On the right side of the stomach (fig. 3) the demarcation of the 

 cardiac division is incomplete. The pyloric division (fig-", 2 and 3, P. St.) 

 is large, and posteriorly proceeds as the caecum of the crystalline style (figs. 

 2 and 3, C.C.) The latter is also large, and, gradually curving, traverses 

 anteriorly some distance along the pedal cavity. 



The intestine (fig. 3. In.), as in S. ■•<tri<jiltatnf and T. r/ifi(f<, appears as a 

 groove on the right anterior side of the caecum of the crystalline style, but 

 as far as can be made out, the projection of the muscular liyer between 

 the two cavities is greater, and consequently reducing the channel of com- 

 munication. At the distal end of the caecum the intestine becomes distinct 

 and returns a part of the way along the dorsal surface. Leaving the caecum, 

 it pursues a loose folded course to the dorsal surface of the pyloric division, 

 then, turning posteriorly, continues as the rectum (fig. i, R.) over the 

 posterior adductor muscle to the exhalent siphonal chamber. 



The liver (fig. i, L.) lies laterally and ventrally to the stomach, but by 

 far the greater part is underneath it. 



Nervous system — The nervous system seems to closely resemble that of 

 S. ■^fri(jiliatus. 



The Gills. — As in the species of Solectirtus examined by Dr. Ridewood, 

 the lamellae are highly plicate, resembling more particularly those of 

 Sotenocurtus (Tayelus) rufus, in the interlamellar septa rising high up the 

 demibranch, and in possessing a blood vessel at the apex of the plica. The 

 number of filaments in a plica are, however, less. It is'not possible to 

 make out the structure in further detail as the gills are not well preserved. 



