ACADEMY OF NATURAL SCIENCES. 265 



West Coast Genera : 



Limnsea, Lam. 

 Subgenera : 



Limnaa, Type L. stagnalis, Lin. 

 Limnophysa, Fitz., Type L. palustris, Mull. 



Physa, Drap. 

 Subgenera : 



Physa, Type P. heterostropha, Say. 



Bulinus,U. & A. Ads., Type»i?. hyjgnorum, Lin. 



Subfamily Planorbin^e. 

 W. C. Genera : 



Planorbis, Guett. 



Subgenera : 



Planorbis, Type P. subcrenatus, Cpr. 



Helisoma, Sw., Type H. ammon, Gld. 



Menetus, H. & A. Ads., Type ilf. opercularis, Gld. 



Carinifex, W. G. Binney. 



Type C. Newbcrryi, Lea. 



Subfamily ANCYLiNiE. 

 W. 0. Genera : 



Ancylus, Geoffr. 



Type A. Neicberryi, Lea. 



Aeroloxus, Beck. 



Type A. Nuttallii, Lea. 



Gundlachia, Pfr. 



Type G. Calif ornica, Powell. 



Subfamily Pompholix^!, Dall. 



Testa depressa, paucis spiralis, anf. ult. maxima. Columella recta, sine plica. 

 Animalis tentaculis longis, oculiferis, et alius par oculorum, in bases interiores 

 tentaculorum. 



Characters, Shell ; depressed, few wborled, last whorl the largest, without fold 



on the columella. Inoperculate. 

 Soft parts ; foot rounded, tentacles long, bearing eyes ; another pair of eyes 



situated on the inner bases of the tentacles. Fluviatile, phytophagous. 



