No. 465.] GENITALIA OF LYMNÆA. > —— 669 
The true relations of the hermaphrodite portions of the geni- 
talia cannot be understood until the organs are separated and 
spread out, when it is seen that the ovisperm duct divides into 
two branches, one branch forming the prostate, which cares for 
the spermatozoa, and the other branch forming the oviduct which 
carries the ova. | 
Lymnea stagnalis jugularıs Say. 
The genitalia of this variety are in all respects like those of 
variety appressa excepting in color, the prostate being brownish 
yellow, the receptaculum seminis yellowish white, and the rest of 
the female organs yellowish and flesh-colored. 
Compared with the European sz/agnalis, the American varieties 
seem to be almost identical. The figures in Keferstein (Taf. 
103, Fig. 8) differ only in the form of the uterus, which is rep- 
resented as more pyriform, and the bulbous part of the prostate 
islarger. The penis is not clearly defined in the figure. The 
figure in Prasch (Taf. 5, Fig. 7) is almost identical, the male 
organs being shown in much detail The uterus is somewhat 
differently shaped but this may be due to a different point of 
view. There is nothing in the genitalia to separate the varieties 
of stagnalis. 
Lymnaa palustris Müller (= eledes Say). (Fig. 5.) 
Male Organs. — The penis is almost as long as the penis-sac 
and is very slender. The penis-sac is rather long, cylindrical, 
and of large diameter. There are two large, wide, ribbon-like 
retractors attached to the penis-sac and one muscle from the 
head of the penis to the posterior retractor muscle. Protractor 
muscles similar to those of stagnalis. Vas deferens long and 
threadlike. Prostate duct very fine; prostate thick, cylindri- 
cal, connected with the ovisperm duct as in stagnalis. | 
Female Organs.— Vagina long, cylindrical, of narrow diameter, 
enlarging to form a large, thick, pyriform uterus which narrows 
to form the much folded oviduct, which in turn narrows to form 
the ovisperm duct. Albuminiparous gland large. Receptacu- 
