220 Wisconsin Academy of Sciences, Arts, and Letters. 
Species living on Castalia-Nymphoea society is dear water of 
creek or in enclosed bay. 
Amnicola cincinnatiensis. 
PJiysa ancillaria warreniana. 
Ancylus parallclus. 
Planorbis parvus. 
Planorbis hirsutus. 
Planorbis campanulatus. 
Planorbis campanulatus rudentisf 
Lymnoea columella. 
Species living in swampy ponds or in Typha plant societies 
where the water is more or less stagnant. 
Sphcerium occidentale. 
Musculium partumeium. 
Musculium securis. 
Pisidium subrotundum. 
Pisidium abditum. 
Physa gynna. 
Aplexa hypnorum. 
Ancylus parallelus. 
Segmentina armigera. 
Planorbis hirsutus. 
Planorbis bicarinatus unicarinatus . 
Planorbis trivolvis. 
Planorbis binneyi. 
Lymncea stagnalis appressa. 
Lymnoea columella. 
Lymncea megasoma. 
Lymncea lanceata. 
Lymncea obrussa. 
Species living in swales. 
Musculium rosaceum. 
Pisidium abditum. 
Pisidium roperi. 
Ancylus parallelus. 
Planorbis parvus. 
