150 POPULAR CONCHOLOGY. 



having two short tentacula, with eyes at the 

 base; foot large and very thick. — There are 11 

 species recent, and 5 fossil. 



These are all small shells, and are found in 

 European Seas, at Amboyna, the Isle of France, 

 New Holland, &c. 



23. Fissurella. — Shell resembling a Pa- 

 tella, but having a round 

 or oval hole at the apex. 

 Animal, a large and dis- 

 tinct head, having two 

 tentacula, with eyes at 

 the base ; foot large. 

 There are 30 species, of which several are 

 fossil. 



The hole at the apex of this shell, which 

 serves as a passage for water to the branchiae 

 of the Mollusc, which are situated near it, 

 differs in form, varying also with the age of the 

 shell, being in some species round, whilst in 

 others it is oblong, or resembling a key-hole. 

 The shells are generally thick and strong, and 

 often delicately marked with alternate dark 

 and light colours. A few species are found on 

 the coast of England, in the same situations as 



