6 



The next two genera are of slender species here, not 

 found south of the canal in this county, the first being here 

 confined to the Erie canal. The snails feed mainly on the 

 fresh water algae growing on stones and logs. They are 

 active quite late, as I collected Goniobasis Dec. 1, 1884, at 

 Baldwinsville. 

 Pleurocera subulare. Lea,. -A beautiful elevated shell, 



apex grooved, aperture auger-like, somewhat rare. 



intensum. Lea. Similar, intense dark and yellow\ 



pallidum. Lea. Similar, color pale. 

 Goniobasis livescens. MenJce. Bulbous, purple within. 



A yellow variety. 



depygis. Say. Yellowish, often with dull red lines. 



Haldemani. Try on. Slender, rare. Erie canal. 



Yirginica GmeL Large, beautiful, variable, smooth 



or striate, banded or plain, thin or thick. Canal and 



Seneca river. 



gemma. DeKay. Variety of the last. 

 The next two genera are of small bivalve shells, the larg- 

 est not an inch long. Some living in wet leaves, others 

 burrowing in still or rapid waters. They have cardinal 

 teeth in the center and linear teeth at the ends of the hinge 

 margin. 

 Sphaerium simile. Say. The largest. Brown, inflated. 



fabale. Prime. Similar, brown, compressed, hinge 



margin curved, rare. 



striatinum. Lam. Compressed, smoother, rare. 



occidentale. Prime. Oval, yellow, shining, com- 

 mon. In wet woods. 



partumeium. Say. White, angular, inflated, thin. 



truncatum. Linsley. Similar, smaller, compressed. 



transversum. Say. Long, thin, large. Erie canal. 



secure. Prime. Small, rhombic, rare. Rivers. 



solidulum. Prime. Yellow and brown, 



stamineum. Conrad. Inflated, yellow. 

 The Pisidiums are smaller and more inequilateral. 

 Pisidium compressum. Prime. Compressed, beaks raised. 



variabile. Prime. Ovate, thick, yellow, polished. 



abditum. Hold. Oval, yellow, smooth, rare. 



Noveboracense. Prime. Oval, inflated, thin, rare. 



Yirginicum. Bourg. Large, thick, brown, rare. 



ferrugineum. Prime. Globose, beaks raised, rusty. 



