ANATOMY AND PHYSIOLOGY OF A SNAIL, 



39 



The Reproductive Organs. — The reproductive organs of the 

 typical Pulmonate Gastropod may be well divided into three 

 groups, a male group, a female group, and a group common to 

 both the male and female group. The male group contains the 

 penis sac, vas deferens, prostate, and flagelliini ; the female group is 

 made up of the oviduct, dart-sac, receptaculuni senii?iis, allmmini' 

 parous gland, and finger-shaped glands ; the group common to 

 both the male and female portions contains the hermaphrodite 

 glatid or ovotestis, the hermaphrodite duct, the common generative 

 canal, and the cloaca or 

 vestibule. These various 

 parts will be readily seen 

 at a glance in the accom- 

 panying figure of the 

 generative organs of our 

 largest English land-snail, 

 Helix po mafia. The 

 principal organ is the 

 hermaphrodite gland or 

 ovotestis situated in the 

 left lobe of the '* Mit- 

 teldarmdrtise," and con- 

 sisting of numerous fol- 

 licles connected together 

 by connective tissue. The 

 ova and spermatozoa are 

 formed from the wall of 

 the follicle and from 



identical cells, but they pi-. n. -Reproductive organs of H. pomatia. Zd, 



hermaphrodite gland ; Zg, its duct ; Ed, albuminipa- 

 rous gland ; Od, common generative canal ; I'd, vas 

 deferens ; P, protrusible penis ; Fl, flagellum ; Rs, 

 receptaculum seminis ; D, finger-shaped gland ; L, 

 spiculum amoris in the dart-sac ; Go, common gene- 

 rative opening (after Baasen). 



are developed at different 



times, — the former from 



the cells on the outer 



wall, the latter from its 



more central portion. A 



sperniatozoon is a filiform body — the filamentous portion being 



known as the tail — with an enlargement at its anterior extremity 



{head) ; an ovum is a rounded cell without a distinct outer coat, 



as in the higher animals, and it consists of protoplasm con- 



