88 CONCHOLOGY. 



FAMILY ir. 

 Phtllidiacea. Six genera. 

 \. GenvLsPhyUidia. PI. IX. 



A niollusca similar to the preceding genus, without a shell, but 

 its back covered with a rough or coriaceous skin. Inhabits the 

 Mediterranean. Three species. 



Phyllidea varicosa. Phyllidea pustulosa. 



P. ocellata. 



2. Genus Chifonellus. PI. TX. 



Animal. Body creeping, elongated ; middle of the back pro- 

 vided its entire length with a detached, multivalve shell ; the 

 alternate pieces for the most part longitudinal ; sides naked ; 

 branchife disposed around the body ; foot cleft longitudinally by a 

 deep furrow. 



Shell. Each valve with strise radiating from its apex ; the 

 margins serrated ; the base of the last valve obtuse. The testa- 

 ceous plates of this genus are never joined like those of the Chiton, 

 so that the animal can move in every direction. Upon the con- 

 traction of the animal after death, however, these valves become 

 nearly united. Inhabits the seas of New Holland. Two species. 

 Chitonellus striatus. Chitonellus larvjeformis. 



3. Genus Chiton. PI. IX. 



Animal. Body creeping, ovate oblong, convex, round at both 

 extremities ; marginated with a coriaceous skin : the back covered 

 by a longitudinal series of testaceous, transverse, imbricated, and 

 moYcable plates ; head before, sessile, with the mouth placed below, 

 destitute of tentacula or eyes ; branchiae placed round the body, 

 under the margin of the skin ; and orifice at the posterior ex- 

 tremity. 



Shell. Eight imbricated valves, nearly smooth, slightly cari- 

 nated, and rounded at the margins : summit more or less marked 



