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4 Messrs. Hancock and Embleton on the Anatomy of Eolis. 



really gathered from the very limited number and minute size of 

 his specimens. 



We propose to treat of the anatomy of Eolis by describing suc- 

 cessively the various organs, beginning with those of digestion, 

 which will form the subject of the present article. The physio- 

 logy will be found incorporated with the anatomy. 



In PI. V. fig. 16, is given a general view of the viscera of E. 

 papulosa, the dorsal skin having been removed. 



07'gans of Digestion. 

 These consist of 

 1st. An outer and an inner lip, leading to 



2ndly. A buccal mass, composed of a pair of horny plates, pro- 

 vided with strong cutting-edges, and inclosing a spiny prehen- 

 sile tongue, having strong muscles adapted to produce all ne- 

 cessary movements. From the posterior part of the dorsal 

 aspect of this mass passes backward, 

 3rdly. A short constricted oesophagus, which ends in 

 4thly. A ramified digestive cavity ; the ramifications continued 

 into the branchial papillse, and developed into a more or less 

 complicated follicular apparatus for the biliary secretion, 

 being at the same time continued into ovate vesicles which 

 open externally at the apices of the papillse. 

 5thly. A short intestinal tube coming off from the posterior part 

 of the dorsal aspect of the bulb of the stomach, and ending in 

 an anus placed on the right side of the body. 

 6thly. Minute salivary glands. 



The mouth, in Eolis papillosa (an anterior view of which, from 

 a specimen that had been in spirit, is shown in PI. V. fig. 14), 

 opens on the inferior surface of the head and in front of the an- 

 terior border of the foot. It is provided with an external pair of 

 large soft lips, PI. I. fig. 4 a, that divide vertically on the median 

 line. A little within these there is a strong, firm, somewhat com- 

 pressed, muscular layer — the inner lip, PI. I. figs. 4, 6, and 8 b, 

 surrounding an oval vertical space, through which two strong, 

 brown, horny laminae, the cutting-blades of the jaw, PI. II. fig. 2 a, 

 are visible. These blades are seen to be separated by a vertical 

 fissure (PI. V. fig. 14 c) opening into the cavity of the mouth. 

 An inferior view of the mouth of E. olivacea in its natural state 

 is seen in PI. V. fig. 15. 



The buccal mass itself, PI. I. fig. 7, is composed of a pair of 

 large corneous plates, a tongue, and the muscles necessary for 

 the movements of these organs. It is a large and apparently 

 compact body of a subtriangular form, with the sides a little com- 

 pressed. The corneous plates, PL I. figs. 4 «, 9 « «, PI. II. 5, 7, &c., 

 are nearly co-extensive with the general mass, on the sides of 



