PATELLIDiE. 463 



are unlike each other in the position of the gill and in 

 the form of the head. 



Genus gadinia, Gray. 



Shell depresssly-conical, surface radiated ; apex sub- 

 central, or a little posterior ; aperture wide, expanded, mus- 

 cular impression horse-shoe-shaped, the right side shortest, 

 terminating at the siphonal groove ; siphonal groove in 

 the front of the right side of the muscular scar, 



Syn. Mouretia, Soiv. Lyria, Gray. Clypeus, Scac- 

 chi, not Klein. 



Ex. G. Garnotii, Payraudeau, pi. 52, fig. 8. Shell, 

 G. Afra, Gray., fig. 8, a. 



The animals of this genus have very similar habits to 

 those of the Patellidce. Adanson, who first observed 

 them, living on the rocks of the Island of Goree, and of 

 Cape Manuel, named them " Gadin." 



Species of Gadinia. 



Afra, Grarj. Peruviana, Sow. 



costata, Kraiiss. reticulata, Sow. 



Garnotii, Payr. ^ stellata, Sow. 



Fam. PATELLID^. 



Mouth armed with horny jaws; lingual riband very 

 long ; teeth in numerous transverse rows (2'4-2), central, 

 two pairs ; lateral, two on each side, the inner one larger 

 and lower down, vmcini three. Head with a short muz- 

 zle ; tentacles subulate, with the eyes on the outer side of 

 their swollen bases. Mantle-margin fringed j gill on the 



