LYMNAIDZ OF NORTH AMERICA. 229 
Types: Say’s type cannot be found. A specimen received from 
Say is No. 58824 in the collection of the Academy of Natural Sciences, 
Philadelphia ; smithsoniane Lea, six specimens, Smithsonian Institution, 
No. 118700; ferrissi, one specimen, Chicago Academy of Sciences, No. 
2458. 
Tyre Locatity: Indiana for caperata; Loup Fork of the Platte 
River for smithsoniana; Rock Run, Joliet, [linois, for ferrissi. 
ANIMAL: Black or bluish black, lighter below and minutely flecked 
with small, whitish dots, which are scarcely visible except on the top 
of the head; head distinct; tentacles short, flat, triangular; foot short 
and wide, 8 mill. long and 3 mill. wide. The animal is very rapid 
and decisive in its movements. 
Jaw (pl. VI, fig. L): Wide and rather high, the median swelling 
occupying about one-third of the width; ends rather bluntly rounded. 
RADULA (plate IX, figure J): Formula: 2%+1,5474+814181,4, 1370 
32-1-32) ; central tooth with a rather broad, spade-shaped cusp; lateral 
teeth bicuspid, the mesocone very broad, the ectocone very small and 
placed rather high; intermediate teeth tricuspid, the entocone of the 
‘ninth, tenth and eleventh teeth very small and acute, placed high on 
the mesocone, which is smaller than in the lateral teeth; the twelfth 
tooth is very much modified, with the three cusps about equal in size; 
marginal teeth claw-like, the entocone split to form from three to four 
small cusps, the mesocone and ectocone reduced in size and a small 
cusp appearing prominently above the ectocone. There are over eighty- 
five rows of teeth. 
In the Mollusca of the Chicago Area, the writer figured a radula 
with but seven laterals, but the normal number is eight. The radula 
figured on page 272 for the short-spired caperata is incorrect, no speci- 
mens being subsequently studied which gave such a formula. 
GENITALIA (plate XIII, figure D): Male organs: Penis short, 
two-thirds the length of the penis-sac, which is large and cylindrical ; 
vas deferens a trifle longer than penis and penis-sac combined; pros- 
tate duct about the length of penis and penis-sac ; prostate large, ovately 
cylindrical, rounded at both ends; retractor muscle of penis enlarged 
at its insertion in the columellar muscle; penis-sac retractor enlarged 
‘at its junction with the penis-sac, about three-fourths the length of 
the penis retractor; the two retractors are joined at their insertion in 
the columellar muscle. 
Female organs: Lower portion of oviduct narrow, short; first 
accessory albuminiparous gland very large, bulbous; receptaculum 
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