476 PHILOSOPHY OF ZOOLOGY. 



is there any thing accurately known with regard to the pe- 

 cuhar nature of their hermaphroditism. 



43. Chitonellus. Dorsal plates not imbricated. 



In this genus, instituted by Lamarck, (Hist. Nat. des 

 Animaux sans Vertebres, vol. vi. p. 316.), the shells are 

 slender, narrow, and are disposed longitudinally, and not 

 in contact, along the middle of the back, leaving the sides 

 of the cloak naked. Two species, C. lavis and striatus 

 were brought from New Holland, by Peron and Le 

 Sueur. 



(2.) Body naked. Infero-branclna. 



44. Phyllidia. Anus placed dorsally near the extre- 

 mity of the cloak. 



The body, in the animals of this genus, is ovate. The 

 foot is narrow in front. The cloak is broad, coriaceous, 

 and destitute of a shell. Towards its anterior extremity 

 are two cavities, from which issue the retractile superior 

 tentacula, as in the genus Doris. Nearly at the posterior 

 extremity is another cavity, containing the anus. This 

 opening, though similar in situation to that of the Doris, is 

 merely a short simple tube. The head is immediately 

 above the anterior margin of the foot, above which is the 

 mouth, having a small conical feeler on each side. Under 

 the margin of the cloak on the right side, and about half 

 way between the mouth and the middle of the body, are 

 two openings, in a tubercle, for the organs of generation. 

 The branchise consist of slender complicated leaves, which 

 surround the body between the foot and the cloak. The 

 circle is interrupted at the head and at the tubercle of gene- 

 ration. 



The mouth is destitute of jaws. The gullet is simple, 

 ending in a membranaceous stomach. The pylorus is 

 placed near the cardia, and the intestine goes directly to 



