PLATE XV. 



1 i The Argonauta argo sailing, 



2. Ocjthoe Cranchii, Leach, sitting within the shelh 



3. Clio Borealis. 



a. The body. 



b. .. viscera seen through the common coverings. 



cc. .. tubercles of the head, and the holes into which the three tenia- 



cula on each side retire. 

 dd. .. branchiae and fins. 



4. Pneumodermon, front view. 



a. The body. e. The chin or pointed fleshy appen- 



b. .. head. dage. 



c. .. mouth. Jf. .. fins. 



dd. .. lips. g. .. branchiae. 



h. .. trunk of the branchial vein. 



5. Pneumodermon, with the skin divided to shew the position of the peri- 



cardium and fleshy tunic. 

 i. The auricle. 

 k. .. pericardium. 



II. .. fleshy tunic with its longitudinal fibres. 



6. The Eolis, placed obliquely, shewing the belly and right side. 



7. Scyllcea pelagica, on the right side. . 



HH. The under surface of the foot hollowed into a deep furrow, by 



which it suspends itself. 

 G. .. mouth. 



AA. .. two tentacula. ' 



BC. Two pair of membranous flexible i These and the back bear the 

 wings. i branchiae in the form of little fi- 



D. A crest on the tail. 1 brous tufts. 



E. The orifice of generation. 



F. .. orifice of the anus. 



