244 THE CHICAGO ACADEMY OF SCIENCES. 
foot; the base of the foot is whitish; length of the foot 2.00 
mill., width 1.00 mill. 
Yaw: Very much arched, the ends square and the whole 
length very uniform in width; the concave portion bears a very 
well-developed median projection; the anterior surface is lon- 
gitudinally striated (Fig. 73, J). 
Radula formula: 75;+3+8+4+§+3+,25 (14—I1—14); 
central tooth with a base of attachment a little longer than 
wide; almost rectangular, with a broad reflection which bears 
the short cusps, rather stout, of which the center cusp is the 
longest; the lateral teeth (6) are similar but asymmetrical, 
Safes a3! 
J 
Fig. 73. 
Radula of VERTIGO OVATA Say. (Original.) c, central tooth; 1, first 
lateral; 5, fifth lateral, modified; 11, typical marginal; J, jaw. 
tricuspid, the inner cusp’being large and the two outer cusps 
small, the inner cusp reaching half way to the lower border of 
the base of attachment; the outer laterals (3) are somewhat 
modified, the inner cusp becoming shorter; the marginal teeth 
(5) are low and wide and serrated, the inner cusp being quite 
large and the outer cusps (3-5) being quite small. There are 
about go rows of teeth (Fig. 73). 
Genitaha: Unknown. 
Distribution: North America and parts of Europe. 
Geological distribution: Pleistocene. 
Hlabitat: Found rather plentifully under sticks, stones, 
leaves, etc., in moist places, especially along the banks of riv- 
ers, ponds and creeks. 
Remarks: This species is at once distinguished by its 
dentate aperture and the peculiar constriction of the last whorl. 
Zonites upsont Calkins is probably nothing but the young of this 
species. Most, or all, of the Pup are very small when young. 
