180 UNIVALVES HALIOTIS. 



three to seven are generally open, and the others per- 

 fectly closed. The H. parva is remarkable for the large 

 elevated rib or angle on its back. 



The second division consists of the imperforated spe- 

 cies. The H. imperforata, which has an ovate form, 

 with an exserted spire, and prickly ribs, is a charac- 

 teristic specimen. 



The species which may be noticed as rarieties of the 

 genus are the H. pulcherrima, H. glabra, H. australis, 

 H. parva, H. imperforata, and H. impertusa. 



The Haliotides are found on the shores of Europe, 

 Africa, and India, where, like the Limpets, they adhere 

 to the rocks, fi'om which they are with difficulty removed. 



The name of the genus is derived from aXg ^ra sea- 

 ears, in reference to the habitat and form of the shell. 



Division 1. — Shell perforated. 



Family 1. — Roundish or ovate. 



Sdentijic Name. Locality. Common Name. 



Midse • • • • East Indies, Mauritius, 



Cape of Good Hope • Midas' Ear 



Pulcherrima King George's Sound • • Beautiftil • ■ do • • 



Virginea • New Zealand Iridescent • do • • 



Tuberculata Europe, West Indies Common • • do • • 



Striata Asiatic Ocean, Barbary • Wrinkled • do • • 



Bislriata Africa • • Double-lined do • • 



Varia East Indies Rough striated do 



Marmorata Africa, East Indies • • • • Marbled • . do • • 



Glabra South Seas Smooth mottled 



Australis New Zealand Rough plaited do 



Gigantea N. Holland, N. S. Wales Gigantic • • do • • 



i"s New Zealand Iris do • • 



Cracherodii California Cracherode's do 



