436 THE CHICAGO ACADEMY OF SCIENCES, 
Ecotocy: “This form is abundant in Washington Harbor, and 
with Limnea stagnalis constitutes the characteristic molluscan life of 
this station. The specimens collected were found clinging to the rocks 
under the same conditions as L. stagnalis. It was also found to occur 
commonly in the rock pools on the Minong Trap promontory (Adams; 
Ruthven). 
Remarks: Pilsbryana differs from emarginata (as herein under- 
stood) by its less rotund shape and particularly by the entire absence 
of the inner lip emargination. It is, however, very closely allied to the 
conical race known as canadensis, differing, as indicated by Walker, by 
its darker color and more inflated spire whorls. The Isle Royale 
emarginata appear to be transitional forms between typical emarginata 
and the race canadensis, many specimens have a spire quite as wide as 
either emarginata or pilsbryana, while others have the sharp conical 
spire of canadensis. The characteristic of the inner lip will immed- 
iately distinguish pilsbryana from all related species. 
Galba montana (Elrod). Plate XLVI, figures 5-8. 
Limnea emarginata var. montana ELrop, Nautilus, XV, p. 111, 1901; Trans. 
Amer. Micr. Soc., XXII, p. 76, 1901; Bull. Univ. Mont., Biol. Ser., No. 3, -pp. 
112, 173, 1902. 
Limnea emarginata montana Keep, West Amer. Sh., p. 314, 1904. 
SHELL: Rather large, elongated, thin; periostracum light brown- 
ish horn or pearl gray; surface shining; sculpture of heavy growth 
lines crossed by heavy impressed spiral lines, giving the shell a beauti- 
fully latticed appearance; rarely malleated; whorls 5% to 6, well 
rounded, rather obliquely coiled, body whorl obese; spire long, acutely 
pyramidal, a trifle longer than the aperture; nuclear whorls as in 
emarginata; sutures well impressed; aperture roundly ovate or elon- 
gate ovate; interior of aperture chocolate colored; peristome thin with 
a slight thickening within; inner lip reflected and forming a broad, 
flat expansion which emargins the large umbilical chink; parietal callus 
not generally notably heavy; columella thickened but not plicate; axis 
slightly twisted. 
Length. Width. Aperture length. Width. 
27.00 13.25 14.70 10.25 mill. (Elrod.) 
29.50 14.25 14.50 S500 Mission Mountains. 
28.50 14.00 13.00 8.00 “ i i 
31.00 15.00 14.00 S75 =! x 
24.50 14.00 12.50 9.001. * = + 
Types: Collection Morton Elrod, University of Montana; topo- 
types, The Chicago Academy of Sciences, four specimens, No. 23709. 
