GENERATIVE ORGANS OF HELIX 



141 



wall of the gland, while the spermatozoa, which are produced in 

 the more central part, are threadlike bodies, generally aggre- 

 gated in small bundles. From the hermaphrodite gland the ova 

 and spermatozoa pass through the upper part of the hermciphro- 

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

 Below the convoluted portion, the duct opens into the albumen 

 gland (a.g.), a large linguiform mass of tissue which becomes 



Fig. 53. — Genitalia of Helix aspersa 

 Miiller, drawn from two indivi- 

 duals in tlie act of union, from a 

 dissection by F. B. Stead. 



A.G, albumen gland. 



C, coecum. 



Cr, crop. 



D.S, dart sac. 



E, eye (retracted) . 



Fl, flagellum. 



H.D, bermapbrodite duct. 



H.DF, ditto, female portion. 



H.DM, ditto, male portion. 



H.G, bermapbrodite gland. 



L, liver. 



M.G, M.G, mucous glands. 



Ov, oviduct 



P.S, penis sac. 



R.M, retractor muscle of penis. 



Sp, spermatbeca. 



V, vagina. 



V.D, vas deferens. 



dilated at the time of pairing, and secretes a thick viscid fluid 

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

 the male and female elements follow the same course, but on 

 their 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 (h.df.), 

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

 uterus') 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 



