PART II. CHELINOTUS. SCUTIBBANCHIA. 355 



TrochiUa Sw. Shell conical, patelliform ; spire central, 



of two or more whorls ; umbilicus closed. 

 T. auriculata. Sow. Man. f. 236. pileus. lb. f. 237, 238. 



Biconia Sw. Patelliform, conical ; internal appendage 

 forming a funnel-shaped fold, not open in front ; 

 apex central, sometimes with the vestige of a whorl. 

 Humph. Conch, f. 11. and 12. 



Chelinotus Sw. Animal cheloniform, broad ; de- 

 pressed ; the mantle much larger than the shell, 

 lobed in front ; tentacula two, short, obtuse ; eyes 

 basal ; mouth circular ; shell ear-shaped, thin, fragile, 

 imperforate ; pillar none. 



Velutina Lam. Animal — } fragile ; shell with the two 

 spiral whorls raised, so as to resemble a Lymnia; no 

 pillar ; epidermis thin, horny. 



laevigata. Sow. Man. f. 337. 



Chelinotus Sw. Shell thin, diaphanous, white, entirely 

 concealed in the back of the animal, which is marked 

 with hexagonal partitions. 



Sigaret de Tonga. Quoy, Voy. d' Astrolabe. 



Coriocella Blainville. Animal broad oval, with the 

 anterior lobes not prolonged, or the back divided as 

 in the last ; shell thin, flexible, membranaceous.* 

 C. niger De Blainville. Man. de Malac. pi. 42. f. 1 . 



Crepidula Lam. Shell boat-shaped; the apex or spire 

 at the narrowest extremity : half of the internal cavity 

 covered by a testaceous plate. 

 C. fornicata. Sow. Gen. f. 1. aculata, lb. f. 5. 



Tribe 3. SCUTIBRANCHIA. The Limpets. 



Shell pateUiform or cup-shaped ; without any spire or 

 internal support. 



Fissurella Lamarck. An oval aperture at the apex, 

 or highest part of the shell. 



* GrifF. Cuv. xii. 68. 

 A A 2 



