GONADS OF SNAIL 



443 



{a) The essential reproductive organ (the ovotestts) is a 

 whitish body near the apex of the visceral spire. It consists 

 of numerous cylindrical foUicles, in each of which both ova 

 and spermatozoa are formed, but not at the same time. 



{b) A much-convoluted hermaphrodite duct of a white 



O.T 



Fig. 252. — Reproductive organs of Helix pomatia. — 

 After Meisenheimer. 



OT. Ovotestis ; H.D., hermaphrodite duct ; /I .G., albumen gland ; F.D.. 

 female side' of common duct; M.D., male side of common duct ; 0., 

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

 dart-sac'; T.D., vas deferens ; FL., flagellum ; P., penis ; M., retractor 

 muscle o'f penis'; AP., genital aperture. 



colour conducts the sex cells from the ovotestis, and leads 

 to- the base of a large yellowish albumen gland. 



(c) This tongue-shaped albumen gland varies in size with 

 the age and sexual state of the snail. It forms gelatinous 

 protein material, which envelops and probably nourishes 



the ova. 



(d) The ova and spermatozoa pass from the herma- 

 phrodite duct towards the head along a common duct, but 



