Chap. XV.] THE SNAIL. 301 



Much larger than the essential organ or ovotestis is the 

 white tongue-shaped albumen gland (al. gl.), between the base of 

 which and the hermaphrodite gland runs a delicate convoluted 

 tube, constituting the upper part of the hermaphrodite duct (h. d.). 

 Into this duct the albumen gland pours its secretion. Below 

 the albumen gland the duct is much folded and puckered, and 

 closely connected with its lower part is the white glandular 

 prostate. Towards its lower end it becomes partially divided 

 into two tubes by an infolded partition. Lower still it gives 

 rise to a shorter oviduct (ov. d.), and a longer vas deferens (v. d.). 

 The oviduct is joined by another tube, the spermatheca (sp.), which 

 higher up bifurcates into two tubes, one ending blindly without 

 dilatation, and in its natural position closely attached to the 

 genital duct, the other ending in a rounded dilatation, which 

 in its natural position lies in the loop of the intestine at the 

 bifurcation of the aorta. Below the point of junction of the 

 oviduct and spermatheca the common tube is joined by the 

 ducts of two muciparous glands (m. gl.), just below which there 

 is a large white oval sac, the dart sac, which, if it be carefully 

 opened, will sometimes be found to contain a sharp calcareous 

 dart, the so-called spicula amoris, on which are four slightly- 

 twisted ridge-like blades. The tube common to the oviduct, 

 spermatheca, muciparous glands, and dart sac, now passes to the 

 vestibule (vb.\ which opens on to the exterior by the genital 

 aperture (g. ap.). 



The vas deferens, after diverging from the common genital 

 duct, takes a curved course. From it a long whip-like diver- 

 ticulum, the flagellum (/.), is given off. Near the vestibule the 

 tube is swollen, and if it be carefully opened it will be found 

 to contain a conical intromittent organ (p. s.). From this point 

 downwards the tube may be everted. A retractor muscle (r. p.) 

 passes back from the tube above this point, and is inserted into 

 the muscular floor of the pulmonary cavity. 



The spermatozoa, after descending the vas deferens, would 

 seem to be enclosed in a sperm capsule, or spermatophore, the 

 flagellum not improbably secreting the material out of which 

 this is moulded. It is a delicate spindle, two or three inches 



