Messrs. Hancock and Enibleton on the Aiuitoiny r^/Eolis. 77 



X. — On the Anatomy of Eolis, a genus of MoUusks of the order 

 Nudibranchiata. By Albany Hancock and Dennis Em- 

 BLKTox, M.D., F.R.C.S.E., Lecturer on Anatomy and Phy- 

 siology in the Newcastle-upon-Tyne School of Medicine. 



[Concluded from p. 10.] 



The oesophagus, PI. 1. figs. 4 c, 6 and 8 b, PI. II. fig. 9, and 

 PI. III. figs. 1, 2 and 4 c, passes from the posterior dorsal aspect 

 of the biiccal mass, and is a much-constricted canal. It is short, 

 longitudinally plicated, and usually bent into the form of an S, 

 so that the apparatus of the mouth can be advanced with facility. 

 It is generally colourless, but in E. coronata and two or three 

 other species it is of a deep rosy hue, appearing as a stain of that 

 colour, immediately behind the dorsal tentacles. It consists of lon- 

 gitudinal and circular fibres, the former of which have been no- 

 ticed in the description of the mnsclcs of the buccal mass. The 

 plica3 seem to be formed by the lining membrane, which we take 

 to be a mucous one, and bv the muscular coat. 



The stomach, PI. II. fig.O, and PI. III. figs. 1,2 and 4</, throngh- 

 ont the entire group is a large pyriform })onch which lies diagonally 

 in the body, the lower end approaching the left side; it is continued 

 in the form of a wide, tapering canal, PI. II. fig. 9, and PI. III. 

 figs. 1, 2 and 4^, along the median Une immediately below" the 

 dorsal skin, and terminates near the posterior extremity of the 

 body in a blind sac. From the pouch and its continuation branches 

 are given off in pairs, not howcNcr in perfect symmetrical order, but 

 always more or less alternating. These branches give off smaller 

 tubes which are continued into the branchial papillae. From the 

 upper siu-face of the posterior extremity of the stomach, just where 

 it is continued into the great central canal, is given off a short 

 intestine, PI. II. fig. 9, and PI. III. figs. 1, 2 and 4 e, which passes 

 backwards, outwards and to the right side, then running for a 

 short distance along the side, turns outwards and upwards and 

 ends abruptly in a nipple-like anus /, generally concealed among 

 the branchial papillae. 



In E. papulosa, PI. II. fig. 9, the anus is situate immediately 

 behind the ninth row of papilla?, and the intestine is considerably 

 dilated a little before its termination : this dilatation is not so 

 conspicuous in other species. In E. coronata, PI. III. fig. 1, the 

 anus is placed amidst the papilla? in the second clump and close 

 behind the fourth row, and in E. olivacea, PI. III. fig. 2, the 

 nipple is seen about midway between the third and fourth rows. 

 In E. despecta, Johnst., PI. III. fig 4, it is between the first and 

 second branches. 



This portion of the digestive apparatus, i. e. the intestine and 



