217 



depended upon to furnisli a dozen specimens any smamer afternoon. 

 The animal is long and slender, of a whitish color and very timid. 

 Greater diameter H-3, height 1-4 mm. 



Strohila lahijrinthica, Say. — The normal form of this shell resem- 

 bles C. falvus in size and color, but its surface is strongly^ marked with 

 raised lines of growth, and the aperture avraed with six rib.s, three of 

 which are thickly set with sharp projections pointing outward. The 

 yielding tissues of the animal pass over these witliout catching, but an 

 intruding insect or other enemy would find his progress effectually barred 

 by them. The color of the shells is genei-ally brown, but I have found 

 several examples which are of a chalky white. These albinos were taken 

 living under troughs used in catching sap in a grove of sugar niapleij 

 in Hidl. A favorite station for this shell is in mossy crevices in 

 rocks, where it is sometimes found in lai-ge numbers. From between 

 ledges in Brigham's quarry I have taken it in great abundance. 

 Greater diameter 2-4, height 2 mm. 



Steiwtrema monooon, Rackett. — This species, which was first de- 

 scribed from Canada, belongs to a small grou[) of distinctively American 

 shells. It is common here in or near woods, and off en in verv dry 

 stations, but nowhere do more than a few occur together. While it 

 loves company it seems always satisfied with one or at most two com- 

 panions. Its constant occurrence in twos and threes under the one loo' 

 or stone is perhaps something more than a mere coincidence. It 

 varies considerably in elevation and elightly in diameter. I have not 

 found any whose greater diameter is less than 9 or more than 1 2 mm. 

 The umbilicus in some specimens is wide and open, and in others from 

 the same localities is so narrow as to be concealed by the reflection of 

 the peristome. This latter form has been called var. frateriia, but it is 

 not, I think, deserving of recognition even as a variety. On the other 

 hand, the small, globose form termed var. leail, which is never found 

 here, though common in the Manitoulin Island.s, seems to me clearly 

 entitled to specific rank. The young of aS'. monodon liave a sim[)le lip, 

 are brown in color, strongly keeled, and always covered with a velvety 

 growth of hair-like projections. With age the lip thickens and becomes 

 reflected, one tooth is formed on the labium and another within the 

 aperture between the u[)per and lower walls of the last whorl. Lastly, 



