SPECIAL ANATOMY. 67 



onoe very easily settles their true nature ; although, even without this 

 mode of analysis, we would suppose the epididymis would indicate the 

 character of the gland of which it is the duct, and leave the remain- 

 ing two organs to be considered as belonging to the female apparatus. 

 In Helix the structure of the testicle consists of dense fasciculi of 

 short ccecal pouches, which are simple, bifurcate, or trifurcate. These 

 contain polygonal spermatophori, which are finely granular with a round 

 nucleus, or filled with granular globules of uniform size, or with coils or 

 bunches or fasciculi of spermatozoa. The epididymis always contains, 

 more or less, and is frequently distended with, a white, silky, filamen- 

 tous substance, composed of spermatozoa. The latter consist of very deli- 

 cate and, comparatively, enormously long filaments, terminating, at one 

 extremity, in a thickened head. They vary in length in different spe- 

 cies of these gasteropods. The head assumes two principal forms ; it is 

 either sigmoid and pointed, as in Mesodon albolabris, Mesodon multili- 

 neata, etc., or else it is spiral and pointed, as in Patula alternata, Pa- 

 tula solitaria, etc. In the vas deferens the spermatozoa may often be 

 detected in movement, which is slow and vibrating in character. 



The prostate gland, although situated along the tract of the oviduct, 

 evidently belongs to the male apparatus, as is proved by its emptying 

 solely into the vas deferens in Veronicella, and in its being placed be- 

 tween the termination of the epididymis and the commencement of the 

 vas deferens only, as is very conspicuously observed in Succinea. In 

 structure, it is composed of closely packed, tortuous, tubular, simple 

 follicles, lined with short, thick, pyramidal epithelia, which are densely 

 granular, and contain a round, nucleolated nucleus. The object of this 

 organ probably is to dilute the very tenacious spermatic matter as it 

 oozes from the epididymis into the spermatic groove on the inner side 

 of the oviduct. 



In all the terrestrial gasteropods examined, there was found a small 

 glandular body, from which proceeds a short duct to join the termina- 

 tion of the epididymis. It consists of from two to nine rounded folli- 

 cles joining a common duct, and, from the constancy of its existence, 

 must be deemed important. 



The ovary is soft and homogeneous in appearance ; viewed by the 

 microscope, it is" found to be almost wholly composed of immature ova, 

 polygonal cells with a germinal vesicle and macula. 



The sides of the oviduct are soft, and in great measure composed of 

 a tissue consisting of large polygonal cells, with from one to five small 

 round nuclei. 



