404 THE MOUNTAIN. 



onomies, and the endless propagation of names by natural- 

 ists ambitious to pile up new species. The gauntlet which 

 one shell (the Anodonta cygnea) has run, is a curious com- 

 ment upon this subject. This single species has been de- 

 scribed and catalogued under five different genera, with 

 seventy-five specific names, by seventy-six different authors. 

 The following table will show the present disposition of the 

 family as arranged with great labor by Mr. Lea : 



FAMILY NAIADES. 



I. GENUS MARGARON : 



1. Subgenus Triquetra, 



Having a cardinal and lateral tooth, and furnished with two 

 siphons. 



2. Subgenus Prisodon, 



Having a cardinal and lateral tooth transversely striate, 

 and furnished with tAvo siphons. 



3. Subgenous Unio, 



Having a cardinal and lateral tooth. 



4. Subgenus Margaritana, 



Having one tooth (cardinal.) 



5. Subgenus Monocondyloea, 



Having a simple callus. 



6. Subgenus Dipsas, 



Having a linear tooth under the dorsal margin. 



t. Subgenus Anodonta, 

 Having no teeth. 



II. GENUS PLATIRIS : 



1. Subgenus Iridina, 



Having a granulate dorsal margin, and furnished with two 

 siphons. 



2. Subgenus Spatha, 



Having a dorsal margin non-crenulate, and furnished with 

 two siphons. 



3. Subgenus Mycetopus, 



Having a straight, smooth, dorsal margin, and furnish^ 

 with a long extensile foot. 



