MOLLUSCA. 43 



The species considered by the older naturalists as shells 

 and mollusca, are in this system of Lamark distributed into 

 three great divisions or classes, which he has denominated 

 CntRHirEDA, CoNcniFERvE, and MOLLUSCA. These classes 

 he has subdivided according to the following tabular view : 



CIRRIPEDES. 



Animalia mollia, capite oculisque carentia, testacea, fixa. 

 Corpus subresupinatum, inarticulatum, tegument! appen- 

 dice involutum, disuper brachiis lentacularibus, cirratis, 

 multiarticulatis instructum. 



Os subinferum, non prominulum ; maxiilis transversali- 

 bus dentatis per paria dispositis. Brachia numero varia, in- 

 equalia, biordinata ; singula cerris geminatis, setaceis, mul- 

 tiarticulatis, ciliatis tegumento corneo indutis, pediculo im- 

 positis. Anus tubum proboscedeum terminans. 



Medulla longitudinalis nodosa, branchiae externae, inter- 

 dum absconditae ; circulatio corde vasculisque confecta. 



Testa vel sessilis vel pediculo flexili tendineo elevata ; 

 valvis pluribus modo mobilibus, modo ferruminatis, tegu- 

 ment! appendice intus vestitis. 



ORDRE PREMIER. CIRRHIPEDES SESSILES. 



* Leur corps n'a point de pedoncule, et se trouve enferme dans une 

 coquille fixee sur les corps marius. La bouche est a la partie su- 

 perieure et anterieure du corps. 



1. Opercule Quadrivalve. 



GEN. Tubinicelle, Coronule, Balane, Acaste. 



2. Opercule bivalve. 



GEN. Pyrgome, Creusie. 



ORDRE SECOND. CIRRIPHEDES PEDONCULES. 

 Leur corps est soutenu par un pedoncule tubuleux, mobile, dont 



