28 



AMERICAN JOURNAL 



V, simplex, Crld. 

 " tridentata, Wolf. 



CARYCHIUM, Say. 

 C. exiguum. 



LYMN^A, Lamarck. 



L. umbrosa, Say. 

 " reflexa, '• 

 " caperata, " 

 " desidiosa, " 

 " humilis, " 

 " exigua, Lea. 

 " curta, " 

 " parva, " 



PHYSA, Draperoaud. 



P. gyrina, Say. 

 " hypnorum, Drapernaud. 

 " Ilildrethiana, Lea. 



HELISOMA, Swainson. 



H. trivolvis, Say. 

 " bicarinatus, Say. 



MENETUS, H. and A. Adams, 

 M. exacutus, Say. 



GYRAULUS, Agassiz. 



G. deflectus, Say. 

 " parvus, '• 



PLANORBULA, Hald. 

 P. armigera, Say. 



ANCYLUS, Geoffrey. 

 A. tardus, Say. 



VALVATA, 0, P. MiJller. 

 V, tricarinata. Say. 



MELANTHO, Bowditch. 



M. subsolida, Anth. 

 " rufa, Hald. 

 " exilis, Lea. 



VIVIPARA, Mont. 



V. intertexta, Say. 

 " subpurpurea. Say. 

 " contectoides, Binney. 



SOMATOGYRUS, Gill. 



S. isogona, Say. 



AMNICOLA, Gld. and Hald. 



A. decisa, Hald. 

 " limosa, Say. 

 " porata, Say. 



" Cincinnatiensis, Anth. 



BYTHINELLA, Leach. 



B. obtusa, Lea. 



POMATIOPSIS, Tryon. 



P. Cincinnatiensis, Lea. 

 " lapidaria. Say. 



PLEUROCERA, Rafinesque. 



P. subulare, Lea. 

 " Lewisii, " 



GONIOBASIS, Lea. 



G. gracilior, Anth. 

 " livescens, Menhe. 



SPH^RIUM, Scopoli. 



S. solidulum, Prime. 

 " triangulare, Say. 

 " transversum, " 

 " sphsericum, Anth. 

 " rosaceum, Prime. 

 " occidentale, " 



PISIDIUM, Pfeiffer. 



P. abditum, Hald. 

 " variabile, Prime. 



UNIONID^. 



UNIO, Brug. 



U. multiplicatUs, Lea. 

 " pustulatus, " 

 " pustulosus, " 



