POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 255 



Generative system 

 Plates 7, 8 



The H e 1 i c i d a e and Limacidae are hermaphroditic, and 

 the hermaphroditism is most complete, having complex male and 

 female organs separated from each other, but so arranged that 

 self-impregnation is impossible, the union of two animals being 

 necessary to reproduction. 



The generative organs consist of the penis, vas deferens, sper- 

 matic duct, oviduct, uterine canal, albumen gland, hermaphroditic 

 duct, consisting of the fallopian tube and spermatic duct, and the 

 ovotestis. On the right side of the foot, about on a line with the 

 beginning of the superior tentacles, is an orifice known as the 

 genital orifice. It presents the appearance of a short slit with 

 the margins in contact, but is capable of great distension. It is 

 from this orifice that the penis is protruded during coition, and 

 into which the penis of the other animal is inserted. Leading 

 from this orifice is a short chamber or tube, known as the cloaca, 

 atrium^ or genital vestibule, connecting with the penis and 

 vagina. The orifices of these two organs are situated side by side, 

 that of the penis immediately in front of the vagina. 



The penis is a long, cylindric body of a glistening white color, 

 occupying the dorsal anterior part of the foot, nearly straight, 

 very slightly curved. Its walls are strong^ thick and composed 

 of muscular fibers. At the base of the penis the walls are very 

 much thickened, and abruptly turned back exteriorly (pi. 8, fig. 

 1, 2). The inner surface of the walls is plicated (pi. 8, fig. 3). The 

 lining membrane along the bottom of the penis is elevated into a 

 very strong muscular fold (the "pilaster"), nearly filling the 

 interior of the penis (pi. 8, fig. 3). The plications of the inner sur- 

 face of the walls are surmounted by papillae (pi. 8, fig. 4). The 

 plications of the lining membrane of the penis, and the muscular 

 fold as seen in the penis laid open longitudinally, and in the trans- 

 verse sections, under a low magnifying power or hand lens present 

 a very beautiful appearance. 



The vagina and the spermatheca or receptaculum seminis are 



