290 



POPULAR CONCHOLOGY. 



compressed; labial palpi large, lanceolate.* — Numerous 

 species ; also fossil. 



Anodonta cygnea. 



These shells lie buried in the sand or mud of lakes and 

 ponds, and are found distributed in every quarter of the 

 world; the valves are thin, large, pearly, and covered with 

 an epidermis; from their shape and lightness they are used 

 in France for skimming milk. A. cygnea is British. 



Mr. Lea of Philadelphia, who has studied this family 

 with great attention, says that there are as many as six 

 hundred thousand young Anodontas often present in a 

 single adult specimen. Dipsas of Leach is a sub genus. 



Ieidina. Lam. — Shell very iridescent,; equivalve, in- 

 equilateral; hinge very long; teeth 

 small, like little tubercles, and nu- 

 merous; ligament external, long 

 and marginal. Animal, mantle 

 closed behind and lengthened into 

 two, unequal, very short tubes; 

 the other parts of the body like 

 the animal of the Anodonta. — 4 or 5 species. 



Iridina exotica is found in the rivers of warm climates, 

 the Nile, and other African rivers; the shell is rather 



* Forbes's British Moll. 



