$04 ON THE CLASSES OF THE 



Linnseus ; animals that live principally in marshy of 

 stagnant water, where they swim by means of the motion 

 of their antenna? and feet. These projecting from a cleft 

 or longitudinal opening between two scaly or testaceous 

 plates, with which the body is covered, are so placed that 

 they can only move vertically, and not, like the legs o* 

 other aquatic Annulosa, horizontally. The two testaceous 

 plates form a sort of bivalve shell, to the anterior part only 

 of which the body of the creature is attached. One of 

 these extraordinary animals, which now constitutes the 

 genus Cypris, is thus beautifully described by Linnaeus : 

 " Testa semine Brassier major, ovata, oblongiuscula, utrin- 

 que ceqaalis, antice gibba et parum retusa, adeoque omnino 

 Concha,; sed in Conchis apertura est a latere tenuiore et 

 card o ubi gibba magis est ; contra vero in hac; h&c ex- 

 tracta ex aquis iota clauditur ut crederes semen cujusdam 

 plantce; in aquis dum Mat, jurares concham esse" Here 

 then we have a bivalve shell opening and shutting by means 

 of a ligament, and inclosing the animal almost entirely; and 

 yet Linnaeus, notwithstanding the great attention which 

 he paid in general to outward forms, perceived that it was 

 not a Mollusque. How unaccountable then it appears 

 that not only Linnseus, but even Cuvier, should consider 

 another animal to be truly molluscous, when it has 

 nothing whatever in common with the Mollusca but an 

 external shell or shells enveloping the whole body ! 



Cirripeda. Leach. 



" Nous void" says Cuvier in his Memoire sur les Ana- 



tifes, " nous void arrives a des animaux bien different 



de tons les Mollusques dont nous avons parlejusqu' d prk- 



se}U; des membres comes, articulcs en quelque sorte, 



