/;/ trod ltd ion to Am ma I Morphology. 



o i 



and has appended to it a multifimbriated prostate. 



The end of the vas deferens is muscular, elongated 



as a penis often with a long flagel- Fig. 33. 



lum. The spermatozoa are united by 



albuminous matter into masses or sper- 



matophores. In Helicidae there is ap- 

 pended to the male organs an eversi- 

 ble sac, whose papillary mouth is close 

 to the opening of the mucous glands ; 

 within this the epithelium is calcified 

 into a sharp quadrangular dart, vary- 

 ing in shape in different species. This ' 

 is everted, and is used previous to the 

 mutual impregnation of two indivi- 

 duals as an organ of irritation. Its 

 use lasts about two hours in a snail, *; 

 and is followed by a 5-7 minutes' im- 

 pregnation. In Limax the two indivi- ^uterus. 

 duals twist spirally round each other in coitu. Self- 

 impregnation has only been noted in Tergipes Ed- 

 wardsii, and Limnaea auricularis, in the whole class. 



i<- dart sac 



Heteropods are dioecious: the penis of the males is 

 a projection of the body wall with no sac, but with a gland- 

 ular extremity, on the right side ; and in Pterotrachra a 

 '.1 sucker is added. The lobed testis occupies the 

 part of the nucleus, and from the opening of tin- vas 

 i ciliated groove leads to the testis. In tin- females 

 same position as the testis (often only 



distinguishable from it by its contents), an oviduct, albumm 

 gland, uterus and vagina. Prosobran< hs an- nmstlv din-cious 

 (except Chiton and Valvata). Some (Cymba, Littorina, 

 Paludina), like the Pulmonat pliora ventri 



Clausilia similis, Pupa umbilicata and marginal'.-, Helix ru- 

 pestris, and some species of Achatincll.i and Yitrina, arc 



