134 Wisconsin Academy of Sciences, Arts, and Letters. 
Pisidium minusculum St. Lake Butte des Morts, rare. Types of this species 
were from the Fox Eiver. 
Pisidium sargenti St. Lakes Winnebago and Butte des Morts, not common. 
Pisidium adamsi affine St. Lakes Winnebago and Butte des Morts, rare. 
Pisidium strengi St. Same localities as above, not common. Pond in Ter¬ 
rel’s gravel pit. 
Pisidium decorum St. Lake Butte des Morts, rare. 
Pisidium griseolum St. MS. Lake Winnebago, very rare. 
Pisidium milium Held. Lake Winnebago, rare. 
Pisidium walTceri St. Lake Winnebago, not common. 
Pisidum tenuissimum St. Lakes Winnebago and Butte des Morts, common. 
Pisidium scutellatum cristatum St. Lake Winnebago, not common. 
Pisidium vesiculare St. Lake Winnebago, not common.. 
Pisidium medianum St. Lake Winnebago, common. 
Pisidium clavatum St. MS. Lake Winnebago, not common. 
Pisidium splendidulum Sterki. Lake Winnebago, rare. 
Pleuroceridae 
Pleurocera acuta Eaf. Very abundant in Lake Winnebago. 
Amnicolidae 
Somatogyrus suhglobosus (Say). Omro, Fox Eiver, rare. Lakes Winnebago 
and Butte des Morts, common. 
Amnicola limosa (Say). Omro, Fox Eiver, common. Lake Butte des 
Morts, common. 
Amnicola limosa porata (Say). Lake Winnebago, very abundant and the 
dominant form. 
Amnicola judayi Baker. Lakes Winnebago and Butte des Morts. Not com¬ 
mon. 
Amnicola walkeri Pilsbry. Lakes Winnebago and Butte des Morts. Common. 
Amnicola lustrica Pilsbry. Lake Winnebago, rare. 
Amnicola emarginata Kiister. Common in Lakes Butte des Morts and Win¬ 
nebago. 
Bytliinia tenaculata (Lin.) Lakes Winnebago and Butte des Morts, very 
common, especially in vegetation. 
Valvatidae 
Valvata tricarinata (Say). Lakes Winnebago and Butte des Morts. One of 
the most abundant mollusks in these lakes. Five varieties have been noted in 
the lake material; their relative abundance is shown in table 1. 
F. tricarinata simplex Gould 
F. tricarinata hasalis Vanatta 
F. tricarinata unicarinata DeKay 
F. tricarinata supracarinata Baker 
F. tricarinata perconfusa Walker 
