446 succiNEiu^. 



the albumen gland it contracts considerably, enlarging inside tbe 

 latter to a poucb of about 2 mm. in size. This inflation, which 

 I propose to designate as a fecundation pouch, has uot been 

 desci'ibed either in Succinea or other Pulmonates. The same 

 applies to the two seminal vesicles opening out into it. The 

 latter are two club-shaped vesicles, whose solid walls consist of an 

 integument of connective tissue and a non-vibratory epithelium. 

 These large seminal vesicles at once arrest, the attention during 

 preparation, without the aid of a lens. Close to this occurs the 

 opening of the hermaphrodite duet. The efferent ducts of the 

 albumen gland open out on the opposite side. Downwards the 

 fecundation pouch is continued in the uterus on the one hand, 

 and on the other in the male duct, which does not, as in Helix, 

 run for some distance as a groove in the wall of the uterus, but 

 separates above from the uterus at the albumen gland. The 

 fecundation pouch is invested with a cylinder epithelium, which 

 is raised into numerous broad folds, of which sometimes one, at 

 other times several, are covered with epithelium. Immediately 

 below the fecundation pouch the uterus is provided with a short 

 caecum-like appendage, invested by a cylinder epithelium, the 

 walls of whicii are repeatedly thrown into folds and, on account 

 of their white colour, very prominent. Thence the uterus descends 

 in numerous spiral twists around a vessel-trunk, serving as axis. 

 The walls assume a transparent gelatinous aspect. Upon micros- 

 copic examination, the outer layer is found to consist of a 

 homogeneous tender membrane with embedded granules, and 

 invested anteriorly with a large-meshed network of fine vessels, 

 the interstices being occupied by large globular pale cells. It 

 might easily be imagined these were unicellular glands, but no 

 efferent openings could be observed in any of them. 



" If therefore these cells are concerned in the seci'etion of 

 mucus, in which the perfect ova are embedded, their contents 

 must penetrate into the cavity of the uterus through the delicate 

 membrane of these cells. The lower part of the uterus is some- 

 what more dilated and uot coiled. It is very prominent owing 

 to its reddish colour. The narrow and rather short duct of the 

 receptaculum seminis joins the uterus not far from the external 

 genital orifice. 



"The lower portion of the uterus, from this point to the 

 external orifice, may be fitly designated as the vagina. The female 

 genital orifice occurs on the right side, somewhat below and 

 behind the upper tentacle, close to the male orifice. In Succinea, 

 therefore, we do not find a common genital cloaca or vestibule, as 

 in Helix, but, as in Limncea, the male and female genitalia have 

 distinct external apertures. 



" The vas deferens descends along the coiled portion of the 

 uterus and bears where the latter passes into the straightened 

 portion, a rather large, laterally appressed gland — the prostate. 

 The penis, which is provided with a single retractor muscle, is a 

 thick-walled muscular simple tube. It is situate in front of the 



