GENERATIVE ORGANS OF HELIX 



141 



and spermatozoa pass through the upper part of the licrmcqilirodite 

 duct (h.d.), which is always more or less convoluted. Below 

 the convoluted portion, the duct opens into the alhumcn gland 

 (a.g.), a large linguiforin mass of tissue which becomes dilated 

 at the time of pairing, and secretes a thick viscid iluid which 

 probably serves to envelop the ova. Up to this point both 

 the male and female elements follow the same course, but 



Fig. 53.- — Genitalia of Helix aspersa 

 Miiller, drawn from two indivi- 

 duals iu the act of union, from a 

 dissection by F. B. Stead. 



A. G, albumen gland. 



C, caecum, 



Cr, crop. 



D.S, dart sac. 



E, eye (retracted) 



Fl, tiagellum. 



H.D, liermaplirodite duct. 



H.DF, ditto, female portion. 



H.DM, ditto, male portion. 



H.G, licrmapbrodite gland. 



L, liver. 



M.G, M.G, mucous glands. 



Ov, oviduct. 



P.S, penis sac. 



R.M, retractor muscle of jienis. 



Sp, spermatbeca. 



V, vagina. 



V.D, vas deferens. 



on tlieir exit from the albumen gland they diverge. The herma- 

 phrodite duct becomes greatly enlarged, and is partially divided 

 by a kind of septum into a male and female portion. . These run 

 parallel to one another, the larger or female portion (ildf.), 

 through which the ova pass (and which is sometimes termed the 

 utems) being dilated into a number of puckered folds, while the 

 smaller or male portion (h.dm.) is comparatively narrow, and 

 not dilated. At their anterior end, the two portions of the duct 

 separate completely from one another, the female portion being 

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

 deferens (v.d.). 



