390 



PHYLUM MOLLUSC A. 



which can be protruded at the single genital aperture and 

 retracted by a special muscle. Before the vas deferens 

 enters the penis, a long process or flagellum is given off. 

 It is like the lash of a whip, and is as long as the common 

 duct. Its secretion is used in forming a sperm-packet or 

 spermatophore of a large number of spermatozoa, which are 



O.T 



H.D 



D.S 



FIG. 210. Reproductive organs of Helix pomatia. 

 After Meisenheimer. 



O.T., Ovotestis ; H.D.> hermaphrodite duct ; A.G., albumen gland ; F.D., 

 female side of common duct ; Af.D., male side of common duct ; O., 

 oviduct; Jt.S., receptaculum seminis ; M.G., mucus glands; D.S., 

 dart-sac ; V.D.^ vas deferens ; FL. , flagellum ; /*., penis ; M., retractor 

 muscle of penis ; A P., genital aperture. 



compacted together at the time of sexual union partly in 

 the flagellum, partly in the penis. The spermatophore 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 



