10 THE CHICAGO ACADEMY OF SCIENCES. 
marginals show no variation, all being of the usual multicuspid type. 
The center tooth is generally quite uniform in shape, the reflection 
being more or less trilobed with a spade-shaped cutting point. The 
cutting point is difficult to see except with high powers, the opaque 
portion standing out clearly and causing the tooth to appear trilobed 
or tricuspid, thus causing the errors mentioned below. The central 
tooth is very difficult to observe clearly, owing to its small size. It 
has been figured as tricuspid, trilobed and simply ovate by different 
authors. In the Cambridge Natural History, Mollusca (Cooke, 1895, 
p. 235) it is figured as tricuspid, the cusps being as large as those of 
the lateral teeth, unquestionably an error, as no Lymnezid has this type 
of central tooth. 
In studying these radulz it is important to consider only the newer 
perfect teeth, as the older teeth near the mouth are usually much worn 
and hence give a false idea of the true form of the cusps. Figure D, 
plate III, shows two of these worn teeth. Compare these teeth with 
the same numbered teeth in figure A of the same plate. On plates 
VII, VIII and IX the radulz of the various species are figured.* 
d. THE REPRODUCTIVE SYSTEM. Plates IJ, III, IV. 
Like all pulmonates, the Lymnzas are hermaphrodites. The male 
and female systems are, however, separated for the most part, the 
opening of the male being behind the right tentacle, while that of the 
female is at the base of the neck near the respiratory cavity. (PI. III, 
fig. G). 
The organs of the fresh-water pulmonates divide naturally into 
three groups, as follows: 
penis. 
penis-sac. 
Male organs...... vas deferens. 
prostate. 
prostate duct. 
vagina. 
oviduct. 
uterine portion of oviduct. 
receptaculum seminis or spermatheca. 
duct of same. 
albuminiparous gland. 
first and second accessory albuminiparous glands. 
Female organs.... 
ovotestis. 
c to both.. ; 
Sage gamer duct. 
1See the chapter on classification for a further consideration of the specific 
variation of radulae. 
