96 POPULAR CONCHOLOGY. 



Animal, foot short and thick. — 40 species re- 

 cent, 18 fossil. 



Some of the species bury themselves in the 

 sand, and others moor themselves by a byssus 

 to stones, coral, &c. ; a few have one valve 

 larger than the other, and many have a velvety 

 or shelly .epidermis, frequently ending in a 

 deep fringe at the margin. They are found in 

 the Atlantic, Pacific, and Indian Oceans, the 

 Mediterranean, &c. 

 t 56. Pectunculus. — Shell nearly round, 

 equivalve, almost equila- 

 teral; hinge curved, with a 

 line of teeth diverging on 

 each side, those in the 

 middle being sometimes 

 incompletely formed ; liga- 

 ment external, hairy epi- 

 dermis. Animal, foot 

 large. — 20 species recent, 

 15 fossil. 



The Pectunculus is found in the West Indies, 

 Atlantic Ocean, and Mediterranean, where it 

 lives on the sandy or muddy coasts, and moves 

 with the aid of its foot. Many of the species 

 have a soft downy epidermis. No byssus. 



