53 
papers on this region were published. The material collected by Dr. Calm 
is in most respects like that from the original locality in Tomahawk lake, 
Wis. Some of the shells have a longer spire than is typical in this race, but 
they have the same general regularity of the aperture and body whorl 
characteristic of this lake race. The largest specimen measures: length 
50, width 24; aperture length 28-5, width 13-5 mm. They are like Figure 
9, Plate XII, of Baker’s Wisconsin Monograph. The variety is probably 
widely distributed in central and northern Canada. All of the shells of 
the stagnalis group, as well as of most of the species in the Keewatin material, 
are very thin and brittle, as would be expected to be the case with animals 
living in waters surrounded by igneous rocks. 
Stagnicola exilis (Lea) 
Cat, Paslikokogan, and Bamaji lakes, and Bamaji Lake outlet. Not 
common. The individuals are rather smaller and narrower, as well as 
thinner, than the same species as it occurs in Wisconsin. Not recorded 
before from Keewatin or other parts of central Canada. Dali (1905) has 
confused this species with lanceala and kirtlandiana, all quite distinct species. 
Stagnicola palustris alpenensis (F. C. Baker) 
Bamaji lake, common. Excepting for the smaller size and very thin 
shell, due to lack of lime in the water, the Bamaji shells are like the Lake 
Michigan form of alpenensis. It is apparently an ecological variety induced 
by lake conditions. Much the same form was found in Mills lake, Mac- 
kenzie River district, by Whittaker. Some of the material recorded by 
Dali and others as palustris from York Factory, Moose Factory, English river, 
as well as localities in Mackenzie River region, may include this variety. 
Typical Stagnicola palustris elodes was not found by the Calm party, 
Stagnicola eatascopium kempi var. nov. Plate II, two lower rows. 
Type locality: Bamaji Lake outlet on rocks in rapids; other localities: 
lake St. Joseph; Paslikokogan river, in rapid water. Types : Museum of 
Natural History, Univ. 111., No. Z30719; Cotypes, National Museum, 
Canada, Molluscs, No. 4377. 
Shell differing from that of typical eatascopium in being much larger, 
with a larger, wider, in many cases a patulous, aperture, a wider columellar 
callus, a more distinct columellar plait, and usually wider spire whorls. 
The spiral sculpture is more distinct. The umbilicus may be a small* 
shallow chink or it may be tightly closed. 
Length 25 *0; Diam. 15-5; Aperture length 14-0; Diam. 10-0 mm. Type 
Length 24- 0; Diam. 15 0; Aperture length 14 ■ 0; Diam. 9*0 mm. Paratype 
Length 21-0; Diam. 14 0; Aperture length 13-0; Diam. 7-9 mm. Paratype 
Length 19-5; Diam. 13-5; Aperture length 12-5; Diam. 8-0 mm. Paratype 
Ivength 22-7; Diam. 16-5; Aperture length 15-5; Diam. 10*5 mm. Paratype 
This variety of eatascopium is a product of the environment, the 
large patulous aperture being a response to the nature of the habitat, where 
the animal lives on rocks in rapids and a larger foot is necessary for the 
animal to retain its hold on the rock to prevent being swept off by the 
rapidly flowing water. It is very distinct from the graceful, long-spired 
shell of the more quietly flowing waters of the southern rivers. The shells 
