154 THE CHICAGO ACADEMY OF SCIENCES. 
Lymnea stagnalis lilliane BAKER, Nautilus, XXIII, p. 112, February, 1910. 
Lymnea stagnalis var. DAantELS, Nautilus XXII, p. 120, 1909. 
Lymnea stagnalis var. WALKER, An. Rep. Mich. Geol. Surv. 1908, p. 289, fig. 
63, No. 1, 1909. 
Limnea stagnalis ApAMS, Rep. Geol. Sury. Mich., 1908, pp. 16, 17, 18, 21, 
1909. 
SHELL: Elongate-ovate, with short spire and elongated, narrow 
aperture, which is typically longer than the spire; whorls flattened, 
elongated, very flat-sided and sloping, especially the body whorl which 
is cylindrical; spire sharply accuminated ; whorls 5% to 6; body whorl 
elongated, flattened, roundly shouldered; aperture long and narrow, 
slightly expanded; axis strongly gyrate; umbilical region with a very 
minute, narrow chink; sculpture and nuclear whorls as in stagnalis 
ap pressa. 
Length. Breadth. Aperture length. Breadth. 
42.00 22.00 26.00 13.00 mill, 
40.00 19.50 23.50 Tray 
39.00 20.00 24.50 TOON Say 
37.50 19.50 23.75 2100s 
28.00 13.00 17.50 Sao) 
Types: Chicago Academy of Sciences, 5 specimens, No. 24554. 
Type LocaLity: Tomahawk Lake, Oneida County, Wisconsin. 
ANIMAL: Similar to that of stagnalis appressa in form; in color 
varying from yellow to jet black (see ante, page 45 for notes on the 
animal of this race). 
JAw: Similar to that of stagnalis appressa. 
RADULA; Formula) giee ee ea 
(39-1-39) ; the teeth are similar in form to those of stagnalis ap- 
pressa; there are but fifteen laterals, in this respect differing from 
both appressa and sanctemarie which have respectively nineteen and 
eighteen laterals; the intermediate teeth are double those of stagnalis 
and sanctemarie, and the total number of teeth is less. 
GENITALIA: Similar to those of stagnalis appressa; the penis-sac 
retractors are two in number, the penis retractor inserted in the pos- 
terior retractor, as figured on plate XIV, figure A, 2; this arrange- 
ment of the retractor muscles allies this race with appressa rather than 
with sanctemarie, in which there is a distinct penis retractor (see 
plate XIV, figure B). A specimen gave the following measurements 
(dissection No. 24552) : 
Penis. Penis-sac. Vas. def. Prost. duct. Ret. mus. Rec. sem. Shell. 
4.00 14.00 47.00 22.00 5.50 9.50° 43.50 mill. 
