228 Wisconsin Academy of Sciences, Arts, and Letters. 
Quadrula undulata. 
Sphwrium simile, 
striatinum. 
occideniah. 
Musculium partumeium. 
securis. 
rosaceum. 
Pisidium abditum. 
roperi. 
virginicum. 
subrotundum 
Campeloma decisum. 
Amnicola cincinnatiensis. 
Physa gyrina. 
Aplexa hypnorum. 
Ancylus parallelus. 
Segementia armigera. 
Planorbis parvus, 
hirsutus. 
trivolvis. 
bicarinatus unicariatus. 
bicarinatus striatus. 
campanulatus. 
Lymnoea stagnalis appressa. 
calum&lla. 
humilis modicella. 
obrussa. 
Succinea retusa. 
Strobilops virgo. 
Helicodiscus parallelus. 
Pyramidula alternata. 
Vitrea hammonis. 
Euconulus fulvus. 
Zonitoides arboreus. 
Polygyra albolabris. 
Boeeal Species. 
Planorbis campanulatus ruderitis. 
Planorbis binneyi. 
Physa ancillarba warreniana. 
Lymnwa stagnalis lilliance. 
Lymnoea megasoma. 
Lymmcea lanceata. 
Lymnoea emarginata luisconsinensis. 
Pyamidula cronkhitei catskillensis. 
The very great preponderance of the widely distributed 
(45) over the boreal (8) species is brought out strikingly in the 
tables. The land shells secured from this region are of no 
special interest, being of general distribution throughout a large 
portion of the United States and Canada. The same may be 
said of the Pelecypods. 
Among the fresh-water pulmonates, however, there are sev¬ 
eral species of unusual interest. Two new forms of Lymnsea 
