33 
6. PISIDIUM FERRUGINEUM, Prime. 
Smithson. Monogr. 
Massachusetts. 
b.. Western New York. 
7... PISIDIUM VENTRICOSUM, Prime. 
Smithson., Monogr. 
aa... Massachusetts. 
b.. Western New Vork. 
c.…. New Brunswick. 
d. Pisidium rotundatum, Prime. Hab.? 
8. PISIDIUM STEENBUCHII, Morch. 
Bull. Mus. Comp. Zool. Harvard V. 
Greenland. (Ex auctore.) 
9... PISIDIUM OCCIDENTALE, Newcomb. 
Smithson. Monogr. 
California. (Ex auctore.) 
1o.… PISIDIUM ULTRAMONTANUM, Prime. 
Smithson. Monogr. 
Canoe Creek, Ca. 
