142 FEMALE AND MALE ORGANS OF HELIX chap. 



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

 the vaginct (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 spermatheca 

 (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 jusb 

 posterior to the common orifice. 



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

 deferens 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 Jiagellum, in 

 which the spermatozoa are stored and become massed together 

 in the long packet known as the spermatophore. The penis 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 aperture, 

 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 dming 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 true Helicidae is the so-called dart, Liehcs- 

 pfeil, or telum veneris. It consists of ' a straight, or cm-ved, some- 

 times slightly twisted tubular shaft of carbonate of lime, tapering 

 to a fine point above, and enlarging gradually, more often some- 

 what abruptly, to the base.' The sides of the shaft are sometimes 

 furnished with two or more blades ; these are apparently not for 



