Oe are 
i a 29% 
is 
278 THE CHICAGO ACADEMY OF SCIENCES. 
gitudinally banded; surface shining, covered with numerous 
closely crowded growth lines, sometimes showing very fine 
impressed spiral lines which reticulate the surface; the growth 
lines are also wavy and elevated, in some specimens forming 
elevated ridges of considerable size; apex smooth, brownish 
or blackish; whorls six to seven, elongate-rounded, last whorl 
dilated (compressed in some forms), reflexed; spire very long 
and pointed, occupying about two-thirds of the entire length 
of the shell; sutures impressed; aperture lunate or elongate- 
ovate, narrowed at the upper part, very oblique in some speci- 
mens; peristome whitish, thin, sharp, thickened by a heavy 
callus on the inside, the callus chocolate or purplish in color; 
lower part of peristome dilated; columella oblique, with a 
heavy plait across its center, running up into the whorl and 
extending to the apex; the columella callus is heavy, wide and 
spreading, and, with the columella, is reflected so as to com- 
pletely cover the umbilicus; umbilical region indented. 
Length, 36.50; width, 11.00; aperture length, 14.00; width, 7.00 mill. (8111.) 
34.00; “ 10.00; ss 13.00? 0-5 6.00" “2. (BETS 
ve 30.50; “ 9.50; - <i 12.50; .“ 5.50. “ — (8109.) 
¥ AOD LEE AZ OOF ie oo % 15.00; “ 850 “ (8109) 
- DOUG; s. 10.00: s 13.50; “ 650 “ (8110.) 
re 01.00; “ 9.50; 7 12.003 5 5" 1.00) > > ABE 
Animal: Bluish-black or black; foot short and wide, 12.50 
mill. long, 6.50 mill. wide; other characters as in palustris. The 
head is carried but little in advance of the edge of the shell. 
Jaw: As usual. 
Radula formula: 34+8§+19+44 19+8+#4 (40—1— 40); 
central tooth as usual; lateral teeth with a subquadrate base of 
attachment; reflection large, a little longer than wide; bicus- 
pid, the inner cusp very large and sub-bifid, the second part 
represented only by a swelling on the inner side of the cusp; 
the outer cusp is short and narrow, and pointed; intermediate 
laterals and marginals tricuspid, the center cusp long, the outer 
cusps short; as the marginals are approached the reflection 
becomes narrow and the outer cusp is placed nearer the top of 
the tooth; marginal teeth long and narrow, of the usual type 
(Fig. g1). 
Genttaha: Not observed. 
Distribution: Northern United States and Canada, from 
the Atlantic to the Pacific. 
Geological distribution: Pleistocene; Loess. 
