CONCHOLOGY. 127 



4. Haliotis. The Ear Shell. Fifteen species. 

 This genus is very beautiful, and derived its common 

 name from its resemblance to the human ear. The exte- 

 rior is generally tuberculated and loaded with marine sub- 

 stances, which gives it a rough and uncouth appearance, but 

 the interior forms a splendid contrast by its natural irides- 

 cence. Each shell is furnished with a row of orifices near 

 the margin, varying in number from eight upward ; of these 

 from three to seven are generally open, and the others close. 

 These holes are made by the animal as it increases the size 

 of the shell, to admit the passage of a short syphon. 



They are found adhering to rocks like the Patella, and are 

 detached with great difficulty. 



Shell ear-shaped, pearly, recurving, very depressed, more 

 or less oval, with spire very small, very low, almost poste- 

 rior and lateral ; aperture as large as the shell, with mar- 

 gins continued ; the right thin and sharp, the left flat, en- 

 larged, and sharp ; a series of holes, complete or incomplete, 

 parallel to the left margin ; one large oval muscular impres- 

 sion. 



Haliotis Midae. Haliotis asinina. 



H. iris. ' H. glabra. 



H. tubifera. H. lamellosa. 



H. excavata. H. unilateralis. 



H. Australis. H. rugosa. 



H. tuberculata. H. canaliculata. 



H. striata. H. tricostalis. 



H. dubia. 



H. asinina. The asinine Haliotis. 



Internal margin very broad, inside pearly, smooth, shining, 

 iridesent, reflecting green, pink, and orange ; back clouded 

 with brown and green ; striated longitudinally. 



H. costata. The ribbed Hahotis. PL 22, fig. 4, interior. 

 PI. 32, fig. 6, exterior. 



Species with disk rounded anteriorly. 



