214 THE CHICAGO ACADEMY OF SCIENCES. 
small, narrow projection; reflection tricuspid, the central cusp 
very long, rather wide, and reaching to the border of the base 
of attachment; side cusps short and wide; the fifth tooth is a 
modified lateral, with a much shortened central cusp; marginal 
teeth wider than long, reflection with three cusps, the inner 
cusp being longer than the outer and bifid; the outer cusps are 
small and narrow; the eleventh and twelfth marginals have 
three outer cusps instead of two; all.the cusps have rounded, 
well developed cutting points (Fig. 51). There are over 75 
rows of teeth. 
Distribution: ‘Ontario and Quebec to Florida, west to Rio 
Chania and White Oaks, New Mexico (Pilsbry). Manitoba 
(Hanham). 
Geological distribution: Pleistocene; Loess. 
Habitat: In damp situations, under loose bark, in rotting 
wood, and under sticks, stones and leaves. Associated with 
Pyramidula striatella, Zonitoides arboreus, etc. 
Remarks: A small species, at once distinguished by its 
flat whorls and armed aperture. The teeth within the aperture 
are placed as follows: one pair near the aperture; a second 
pair is placed within the aperture, a third or half a whorl from 
the opening, anda third pair(when present) still farther within 
the aperture. Each pair is placed one above the other, the 
superior tooth being at or a trifle above the periphery, and 
the inferior between that point and the base of the aperture. 
When the animal is in motion the shell is carried almost flat, 
the eye-peduncles and tentacles pointing upward at an angle 
of 85 degrees. The anterior part of the animal is much in 
advance of the shell, the latter being placed almost on the 
posterior extremity. This species is fully as abundant as the 
last, and is almost always found associated with it. It is one 
of the neatest of the smaller Helices. 
Subfamily Punctine. 
“Faw composed of'sixteen to twenty-four separate pieces.” 
(Pilsbry.) 
Genus PUNCTUM Morse, 1864. 
Shell: Small, discoidal, aperture subcircular, peristome 
thin. Jaw composed of numerous separate plates, which partly 
overlapeach other. Radula with a unicuspid central tooth and 
