558 



Shells in Massachusetts. 



III. GENUS ANADONTA, Lam. 



Anadonta. 



cataracta, Say. Common Green Muscle, 

 marginata, Say. Blackstone and French Rivers, 

 lugubris, Say. Ponds in Essex Co. 



IV. GENUS CYCLAS. 



Cyclas. 



similis, Say. 

 dubia," Say. 



And two species not described. 



II. UNIVALVES. 



I. GENUS PALUDIN A. 



Paluclina. 



decisa, Say. 

 limosa? Say. 



II. GENUS PLANORBIS. 



Planorbis. 



trivolvis, Say. 

 bicarinatus, Say. 

 armigerus, Say. 

 campanulatus. 

 parvus, Say. 



III. GENUS LYMNAEA. 



Lymnaea. 



catascopium, Say. 

 heterostropha, Say. 

 columella, Say. 



And one species not ascertained. 



LAND SHELLS. 



IV. GENUS HELIX. 



Helix. 



alaboris. Common Wood Snail. 



arboreus, Say. 



tridentata, Say. 



alternata, Say. 



glaphyra, Say. 



thypopdus, Say. 



minuta, Say. 



hirsuta, Say. 



* This does not agree exactly with my specimens of the dubia found in 

 Pennsylvania, but I think it not sufficiently distinct to be separated from that 

 species. 



