REPRODUCTIVE SYSTEM. 



373 



h.d. 



R 



a.g- 



(d) The ova and spermatozoa pass from the hermaphrodite 

 duct towards the head along a common duct, but not at the 

 same time. Moreover, their paths are different, for the 

 portion of the duct down which the ova travel is much 

 plaited, while the path which the spermatozoa follow is a 

 less promiment groove, incompletely separated from the 

 other. Both paths 



are glandular, and the 

 glands on the male 

 side are often called 

 prostatic. 



(e) At the base of 

 this common duct, a 

 distinct vas deferens 

 diverges to the left 

 and leads into a mus- 

 cular penis, which can 

 be protruded at the 

 single genital aperture 

 and retracted by a 

 special muscle. Be- 

 fore the vas deferens 

 enters the penis, a 

 long process or flagel- 

 lum is given off. It 

 is like the lash of a 

 whip, and is as long 

 as the common duct. 

 Within it a sperm 

 packet or spermato- 

 phore is partly formed, 

 but seems to be com- 



Ml. ST. 



FiG. 185. Dissection of Helix pomatia. 

 Mainly after Leuckart. 



!.;-., nerve-ring; s.g., salivary glands on the crop; 



f., foot; d.g., digestive gland opening into mid- 

 gut; /*., heart; /., kidney; r., rectum; I\., 

 hermaphrodite organ in terminal part of digestive 

 gland; h.d., hermaphrodite duct; a.g., albumen 

 gland ; c.d. , common duct, \vith more convoluted 

 oviducal part ; v.d., vas deferens entering penis; 

 //., flagellum ; r.s., receptaculum seminis, with 

 a branch from its duct; m--> mucus glands; 

 iJ.s.. dart sac. 



pleted in the penis. 

 The spermatophore is laden with a large number of sper- 

 matozoa, and is transferred by the penis into the genital 

 aperture of another snail. 



(/) Continued from the oviducal side of the common 

 duct, there is a separate ciliated oviduct. This has a short 

 course, and ends in the common genital aperture. Before 

 it reaches this, however, the oviduct is associated with two 

 structures. The first of these is a long process, as long as 



