Observations on the Terrestrial 



*AURICULID^. 



AURICULIN"^. 



Carychium exiguum, Say. 

 Alexia myosotis, Drap. 



MELAMPIJS"^. 



Melampus bidentatus, Say. 

 * LIMN^ID^. 



PLAlSTftEBIN^. 



Planorbis lentus, Say, 

 Planorbella campanulatus, Say 

 Helisoma trivolvis, Say. 



" bicarinatus, Say. 

 Menetus exacutus, Say. 

 Gyraulus deflectus, Say. 



" jDarvus, Say. 



" hirsutus, Gould. 



" dilatatus, Gould. 

 Planorbula armigera, Say. 



PHYSINjE. 

 Nauta elongata, Say. 

 Physa ancillaria, Say. 



" heterostropba, Say. 



* gyrina, Say. 



Radix ampla, Mighels. 

 " columella, Say. 

 Limnopliysa elodes, Say. 



" desidiosa, Say. 



" caperata, Say. 



" catascopium, Say. 



" humilis, Say. 



ANCTLIN^. 



Ancylus parallelus, Hald. 

 " tardus, Say. 

 " fluviatilis, Say. 

 " avails, Morse. 

 " borealis, Morse. 



* VIVIPARID^. 



Melantho decisa, Say. 



*AMNICOLID^. 



Amnicola decisa, Hald. 

 " porata, Say. 

 " limosa. Say. 



* VALYATID.E. 

 Valvata tricarinata, Say. 



" sincera, Say. 

 Lyogyrus pupoidea, Gould. 



* ITNIONID^. 

 Anodonta fluviatilis, Lea. 



" marginata. Say. 



" implicata. Say. 

 Strophitus undulatus, Say. 



" sculptilis, Ag. 



Alasmodonta marginatus, Say. 

 Margaritana arcuata, Barnes. 

 Lampsilis ocliracea. Say. 



" radiata. Lam. 

 Unio complanatus, Lea. 



* CORBICULAD^. 

 Sphserium sulcatum, Lam. 



" striatinum, Lam. 



" j^artumeium. Say. 



" tenue. Prime. 



" securis. Prime. 



" truncatum, Linsley. 



Pisidium Virginicu7u, Bourgui- 

 " Adamsii, Prime, [gnat. 

 " requilaterale, Prime. 

 " compressum, Prime. 

 " variabile, Prime. 

 " abditum, Hald. 



