142 FEMALE AND MALE ORGANS OF HELIX chap. 



duct separate completely from one another, the female portion 

 being then termed the oviduct (ov.) and the male portion the 

 vas deferens (v.D.). 



Following first the oviduct, we find that it soon widens into 

 the vagina (v.), which is furnished with a pair of mucous glands 

 (m.g.), one on each side. These are much branched, and re- 

 semble little bunches of whitish sea-weed. A little above the 

 mucous glands a long tube diverges from the vagina, which is 

 furnished with a produced coecum (c.) and a pouch, the sjjenna- 

 tJieca (sp.) at the extreme end. In this pouch, and in the duct 

 leading to it, is stored the spermatophore received in union with 

 another snail. Just below the mucous glands the vagina is joined 

 by the dart sac (d.s.), which is more fully described below. 

 Finally, at its lower end the vagina unites with the penis sac 

 at a point just posterior to the common orifice. 



Returning now to the male organs, we find that the vas 

 defereris is the continuation of the male portion of the herma- 

 phrodite duct, after its final separation from the female portion. 

 It passes under the retractor muscle of the upper right tentacle, 

 which has been cut away in the specimen figured, to dissect it out. 

 Just before the vas deferens widens into the penis sac, it branches 

 off into a long and tapering tube, the flagellum^ in which the 

 spermatozoa are stored and become massed together in the long 

 packet known as the spermatojyJiore. The jjeiiis sac (p.s.) is 

 the continuation of the vas deferens beyond the point at which 

 the flagellum diverges. It joins the vagina at its extreme 

 anterior end, uniting with it to form the common genital aper- 

 ture, which cannot be exactly represented in the figure. The 

 penis itself lies in the interior of the penis sac, and is a rather 

 long muscular tube which is protruded during union, but at 

 other times remains retracted within the sac. 



In the Helicidae generally, the form of the generative organs 

 varies with each separate species, sometimes merely as regards 

 the size of the different parts, at others in the direction of greater 

 simplicity or complication. The mucous glands may be absent, 

 and the flagellum greatly reduced in size, or absent altogether. 



The Dart Sac. — A remarkable part of the reproductive 

 system in many of the ti'ue Helicidae is the so-called dart^ 

 LiehespfeiU or telum veneris. It consists of ' a straight, or curved, 

 sometimes slightly twisted tubular shaft of carbonate of lime, 



