OF CONCHOLOGY. 89 



son in the first genus of spiral shells ; 

 and Da Casta, going still further from 

 the point, places it as his second genus 

 of simple shells. 



We see no situation in the present 

 arrangement so well adapted to this 

 genus, as the one it now occupies. 

 It is the most simple of the spiral 

 shells, consequently it now stands 

 in its proper place, as the last of the 

 spiral shells, preceding those shells 

 destitute of a regular spire. 



It is asserted, that as a new hole is 

 added by the animal to the shell, it 

 carefully closes up the next open one 

 to the spire ; by which means the 

 number of orifices are, in general, the 

 same in all shells of one species. 



In Turton's Linne 19 species of 

 Haliotis are described ; and only one 

 has been found to inhabit the British 



seas. 



N 



