6 
Compared with Helisoma trivolvis, the distribution of corpulentum is 
quite restricted, judging by the authentic records. It is a common species 
in the waters of the International Boundary and in the lakes of western 
Ontario. Say found it in Winnipeg (Winnipeck) river, Rainy lake, and 
Lake of the Woods. It is in the National Museum of Canada from the 
following localities and sources: 
2227. Lac Seul. Wm. Melanies, June 20, 1904. 
2260. English river below Manitou fall. Wm. Mclnnes, June 22, 1905. 
2222. Minnitaki lake. Wm. Mclnnes, June 18, 1904. 
2321. Lake of the Woods. J. Fletcher, 1882. 
2229. Sioux Lookout, English river. Wm. Mclnnes, Sept. 29, 1904. 
2228. Lac Seul. Wm. Mclnnes, June 24, 1904. 
2107. Kenora (Rat Portage) above falls. A. C. Lawson, 1884. 
In the museum of the University of Michigan the following records 
occur: 
35678. Kenora (Rat Portage). Fred Steams, coll. 
28228. Kettle falls, Rainy lake. Hon. F. R. Latchford, coll. 
In the collection of the United States National Museum the specimens 
listed below are typical corpulentum: 
347755. Lake of the Woods, northwest angle, Minn. UJ3. Biol. Surv., W. F. 
Kubicheck, Sept. 16, 1921. 
347783. Lake of the Woods, Warroad, Minn. US. Biol. Surv., F. P. Metcalf, 
Sept. 17, 1921. 
251143. Kettle falls. Rainy lake. Hon. F. R. Latchford, coll. 
346628. Kettle falls, Rainy lake. Hon. F. R. Latchford, coll., June 28, 1910. 
361737. Kettle falls, Rainy lake. Hon. F. R. Latchford, coll. 
The museum of the Academy of Natural Sciences of Philadelphia 
contains the following material referable to typical corpulentum: 
127768. West end lac Seul. A. W. Fahrenbruck, 1920. 
It is in the Natural History Museum of the University of Illinois, 
collected by Dr. A. R. Cahn, from the following localities: 
Z32296. Lac la Croix, Rainy River district. 1931. Adult. 
Z32297. Lac la Croix, Rainy River district. 1931. Immature. 
Z32298. Lac la Croix, Rainy River district. 1931. Young. 
Z32349. Basswood River rapids, Rainy River district. 1931. 
Z32319. Northern Light lake, Thunder Bay district. 1931. 
Z29845. Trout lake, Patricia portion of Kenora district. 1928. 
Z32300. Iron lake, St, Louis county, Minn. 1931. 
The typical species is recorded from Manitoba and Ontario by Mozley 
as noted below, but the material may include related species or races. 
None of the specimens has been available for study. 
Indian lake, Falcon bay, Manitoba; Minaki, Sand lake, White Dog, Sword lake 
near Minaki, all on or near Winnipeg river; Fox lake, near Wade, all in Ontario. 
The presence of typical corpulentum in the Mississippi drainage has 
been questioned by the writer, but undoubted specimens of the species in 
several authentic collections remove all doubt of its presence in the head- 
waters of Mississippi river. The records are noted below. 
Mus. Univ. Mich. 47010. Outlet lake Itasca, Itasca State park, Minn. 
Phil. Acad. 121324. Upper Mississippi. C. M. Wheatley, 
It is very doubtful if this species occurs in either Michigan or 
Wisconsin. Walker’s record (Nautilus, XIII, page 133) cites the species 
as simply from Michigan with the comment that it must have come from 
