180 THE CHICAGO ACADEMY OF SCIENCES. 
body whorl; inner lip reflected and widely spreading in old specimens ; 
umbilical chink very small in young or half grown individuals, but 
wide and deep in fully adult specimens. The epidermis is somewhat 
marked by light and dark lines of color, alternating. Nucleus of about 
1% hyaline whorls, not differing in outline from those of Lymnea 
stagnalis appressa. 
Length. Breadth. Aperture length. Breadth. 
23.00 17.00 18.00 11.00 mill. 
20.00 15.50 15.50 9°50) te 
31.00 24.00 24.50 16150) ee 
26.50 21.50 24.50 ALO OM ie 
18.00 112525 13.00 8.00 “ (Half grown) 
15.00 10.00 11.00 HOD a * 
Type: Location unknown. 
TYPE LOCALITY: Not known to the writer. 
ANIMAL: Body flecked with small white spots; mantle marked 
by many black, irregular spots which show through the shell; head 
broad, auriculate; tentacles very long, narrow, tapering; foot broadly 
rounded anteriorly and acutely rounded posteriorly; 18 by 11 mill. in 
a specimen of good size. 
Jaws: Superior jaw low and very wide, strongly arched, about 
one-quarter as high as wide with a distinct rounded median projec- 
tion about one-third the length of the entire jaw; lateral jaws not 
differing from those of Lymnea stagnalis (Pl. V1, fig. D). 
RapuLa: Formula: #}+4+$+3+54+174434+34+3474+8 
(Pl. VII, fig. C) (50-1-50). Central tooth narrow, with a long 
acute mesocone (C); first lateral tooth very broad, tricuspid, the 
mesocone very wide, the entocone and ectocone small; second to ninth 
lateral teeth broad, bicuspid, the mesocone very wide, the ectocone 
emall and rather narrow; the tenth tooth becomes tricuspid by the 
splitting of the mesocone to form a small spade-shaped entocone; the 
eleventh to thirteenth teeth are similar in form, the entocone, however, 
approaching more nearly to the distal end of the reflection in the 
twelfth and thirteenth teeth; the fourteenth to eighteenth teeth have 
a very long and narrow reflection, with two spade-shaped cusps at 
their extremity and two small outer cusps about midway of the reflec- 
tion; the nineteenth to twenty-first teeth are similar, excepting that 
the cusps at the distal end vary from two to four in number ; the mar- 
ginals from the twenty-third to the edge of the membrane are long and 
narrow, with small cusps at their distal ends, and two small cusps on 
the outer margin. There are from eighty to ninety rows of teeth. 

