GENERATIVE ORGANS OF DIOECIOUS MOLLUSCA 



135 



ova and the spermatozoa. These glands are generally known as 

 the ovary in the female, the sperm-gland or testis in tlie male. 



(&) The channels which provide for the passage of the seminal 

 products ; namely, the oviduct in the female, the vas deferens or 

 sperm-duct in the male. 



(c) The external generative organs. 



Dioecious Mollusca. — The connuon LUtorina ohtnsata will 

 serve as a typical instance of a dioecious prosobranchiate, exhibit- 

 ing the simplest form of organs. In the female the ovary, a 

 lobe-shaped body, is embedded in the liver. An oviduct with 



Fig. 49. — Generative and other organs 

 of LUtorina obhcsata L., female. 



A, anus. 



Br, brancliia. 



Buc, buccal mass. 



H, lieart. 



Hep, liejiatic duct. 



I, continuation of 



oesopliagus 

 Ki, kidney. 

 Li, liver. 



M, muscle 



attachment. 

 O', female orifice. 

 Od, oviduct. 

 Oes, oesophagus. 

 Ov, ovary. 

 Ra, radula. 

 St, stomach. 

 U, uterus. 



of 



Fig. .50. — Generative and other organs 

 of LUtorina ohtusata L., male. 



A, anus. M, muscle of attacli- 



Br, brancliia. meut. 



H, heart. Pe, penis. 



I, intestine. Te, testis. 



Li, liver. VD, vas deferens. 



(After Soiileyet.) 



(After Souleyet. ) 



many convolutions conveys tlie ova into the uterus, an ol)long 

 chaud)er which consists simply of a dilatation of the oviduct. The 

 ova descend into the uterus, which is sometimes furnislied with a 

 seminal poucli. In this seminal poucli, or above it, in the oviduct, 

 the ova come into contact witli the spermatozoa. The lower part 

 of the uterus secretes a gelatinous medium (or capside, as the case 



