Family HELICINID.^'. 



74 Hdic'ina (Oligyra) orbiculata, Sat', d. 



Family LlMJs^^ElD.F]. 

 Subfamily Limn^einje 



75 Limn^ea (Eadix) columella, >S'ai!/. 



76 (Limnophysa) desidiosa, Saij. 



77 " humilis, Say. 



78 " rellexa, S'dy. 



79 Pliysa ancillaria, Say. 



80 . gy rin a, Say. 



81 heterostropha, Say. 



Subfamily Plakorbix.e 



82 Planorbis (Gyraulus) parvus, Say. 



83 (Helisoma) bicarinatus, Sa;/. 



84 " trivolvis. Say. 



85 (Menetus) exacutus, Say. 



86 (Planorbis) glabrus. Say. 



87 " lentus, Say. 



88 Segmentina armigera, Say. 



Subfamily Axcylin.is, 



