17 
exterior surface of the body whorl ; at base the lip is adpressed 
and covers the umbilicus ; labrum with a large, prominent, oblique, 
lamelliform tooth ; umbilicus closed. 
Greatest transverse diameter nearly nine-twentieths of an inch. 
Inhabits lower Missouri. 
The teeth of the labrum somewhat resemble those of tridentata; 
but in the form of the groove behind the labrum, and the pillar- 
tooth, it resembles H. hirsuta. Several specimens were found, but 
all dead shells, and destitute of their epidermis. 
H. CLAUSA. — Shell fragile, slightly perforated, subglobular, 
yellowish horn color, above convex ; whorls four or five ; aperture 
slightly contracted by the lip ; lip reflected, flat, white, nearly 
covering the umbilicus. 
Inhabits Illinois. Greatest breadth from one half to three-fiflhs 
of an inch. 
A small and handsome species, which somewhat resembles albo- 
labris, but is much smaller, more rounded, and is subumbilicate. 
This shell also occurs, though,^ pefhaps rarely, in Pennsylvania. 
II. OBSTRICTA. — Shell depressed, with elevated lines forming 
grooves between them ; epidermis pale brownish, naked ; volutions 
five, depressed above, beneath rounded, with an acute, projecting 
Carina ; umbilicus covered with a white callus, indented j mouth 
resembling that of H. palliata. 
Inhabits Ohio. Breadth nearly one inch. 
This species is very closely allied to Helix palliata, but the 
epidermis is not covered with small elevations as in that shell, and 
the Carina is very prominent and remarkable. 
H. ELEYATA. — Shell pale horn color, spire elevated ; whorls 
seven, regularly rounded ; umbilicus none ; aperture somewhat 
angulated ; labrum dilated, reflected, pure white, at base adpressed 
to the body whorl, abruptly narrowed on the inner edge beneath 
the middle, and continuing thus narrowed to the superior termina- 
tion, leaving a projecting angle behind the middle ; labium with a 
large, robust, very oblique, subarquated, pure white tooth. 
Greatest breadth seven-eighths of an inch. Column nine-six- 
teenths of an inch. 
Found rather common in the vicinity of Cincinnati, Ohio. It 
seems to be distantly related to thyroidus by the tooth on the 
labium, but this tooth is much more robust ; it difiers much more 
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