674 THE AMERICAN NATURALIST. [Vor. XXXIX. 
to the distal end of the penis-sac; and the penis muscle, which 
is attached to the head of the penis, is inserted in this muscle 
near its attachment to the columella muscle. Vas deferens and 
innervation as in the other species described. The prostate is 
large and cylindrical at its junction with the prostate duct, but 
becomes very long and narrow at its posterior portion and again 
narrows as it unites with the ovisperm duct. 
Female Organs.— The ovotestis is made up of the usual lobu- 
lated follicles. The ovisperm duct is rather long; the oviduct 
is a much lobed organ, rather long and of large diameter ; it 
enlarges to form a long, cylindrical uterus which suddenly con- 
tracts to form the vagina. The receptaculum seminis is small, 
elongate-ovate in form and connects with the vagina rather high 
up by a narrow duct. The albuminiparous gland is not large 
and is of the usual form. The innervation is as in the other 
species described. 
The organs are colored as follows: penis and penis-sac yel- 
lowish, prostate yellowish or amber-colored, ovotestis yellowish, 
albuminiparous gland greenish, receptaculum seminis pearly 
white, and the other organs yellowish. The muscles are white 
in color. | 
The genitalia of mighelsi differ from those of all the other 
species described in the form of the uterus, which is long and 
cylindrical while the vagina is short and wide. The prostate is 
also differently shaped. The penis-sac is very long and wide 
while the penis is about half its length. It is evident from a 
study of the genitalia of mighelsi and emarginata that the for- 
mer is specifically distinct from the latter. The penis is 
shorter, the oviduct is differently shaped, as well as the pros- 
tate. The shells also exhibit differential characters. 
Lymnea catascopium Say. 
Male Organs — In all respects like those of emarginata. The 
Prostate is also like that of emarginata. The receptaculum 
N I5 more pear-shaped. The uterus is not so swollen, the 
distinction between -vagina and uterus not being very marked, 
and the two organs form a long, somewhat cylindrical sac. 
