AFLIDIUM. CIRRIPEDA. 



E. subgelatinosum, Lam. Animalcules horizontal, with an elonga- 

 ted neck ; orifice not stellated Lam. v. 96. 



Gen. 10. APLIDIUM, Lam. 



Animals biforous, aggregated, very small, living in a common 

 convex fleshy body, fixed, and without displaying particular 

 systems ; six tentacula at the mouth ; anal orifice not appa- 

 rent exteriorly. 



A. sublobatum, Lam. Spreading and divided into yellowish fleshy 

 lobes, which when opened emit a very disagreeable smell. Inha- 

 bits European coasts. Lam. iii. 95. 



CLASS IV. CIRRIPEDA. 

 (Mollusca Cirrhopoda, Cuv.) 



Soft animals., destitute of head and eyes, covered with a shell, 

 and fixed ; body inarticulated, furnished with a mantle, and 

 tentacular, cirrous, many-jointed arms above. 



THE Class CIRRIPEDA, forming the genus Lepas in the sys- 

 tem of Linnaeus, was instituted by Lamarck in 1812, and has 

 since been adopted by Cuvier, Blainville, and other naturalists, 

 as a distinct group of Molluscous animals, intermediate between 

 them and the articulated groups. 



The body in this class is always much shortened, immoveable, 

 and inclosed in a shell, either itself fixed to an extraneous body, 

 or elevated on a tubular and moveable peduncle, which permits 

 some degree of motion. In the first case the shell adheres im- 

 mediately to the marine bodies upon which it is fixed ; while 

 in the other the shell, of which the valves are always distinct 

 and moveable, and inclosing the body more or less completely, 

 is raised on a peduncle of greater or less length. This foot-stalk 

 or peduncle is tubular, tendinous, moveable, more or less contrac- 

 tile, and fixed by its base ; and it does not appear that the ani- 

 mal has the power of changing its attachment, or shifting its 

 place. The tunic or mantle of the Cirripeda in some cases 

 envelopes only a portion of the body, and forms the external 

 coat of the peduncle in those which have a foot- stalk. In others, 

 as in the genera Otion and Cineras, the tunic envelopes all the 

 body, leaving only an anterior opening for the arms. In none 



