HALIOTIS. 117 



these, which have no generic deficiency but that of 

 the foraminal ducts. 



Did the animal inhabiting the shells of one sec- 

 tion diflfer from that which constructs the other, 

 it would not prevent a generic union of them, ac- 

 cording to our system ; but no such fact of their 

 dissimilarity is ascertained. Some of the identical 

 species open and make use of a different number of 

 their syphons. Why may not then a Limax be per- 

 mitted to choose a water-tight receptacle, though 

 his fellows prefer one that is pervious to the winds 

 ♦and waves ? 



The Haliotis, from «Xc, the sea, and cora, ears, 

 is thus denominated on account of its ear-like 

 form. The animal is attached by so adhesive a pro- 

 perty to the surface of the rocks, that it requires 

 the utmost force to disengage it, though by a 

 spontaneous action it is able to remove with facility 

 from place to place. It is probable that in some 

 individuals of this family as in some of Helix and 

 Patella, the shell does not cover the whole body of 

 the Molluscous worm, but merely the vital organs. 



