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 flagellum ; the female group is 

 made up of the oviduct, dart-sac, receptaculum seminis, albumini- 

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

 both the male and female portions contains the hermaphrodite 

 ^land 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 pomatia. The 

 principal organ is the 

 hermaphrodite gland or 

 ovotestis situated in the 

 left lobe of the " Mit- 

 teldarmdruse," 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 Fig. n -Reproductive organs of H. pomatia. Zd, 

 are developed at different hermaphrodite gland ; Zg, its duct ; Ed, albuminipa- 



rous gland ; Od, common generative canal ; Vd, 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). 



times, the former from 



the cells on the outer 



wall, the latter from its 



more central portion. A 



spermatozoon is a filiform body the filau.entous portion being 



known as the tartwith an enlargement at its anterior extremity 



(head) ; an ovum is a rounded cell without a distinct outer coa% 



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



