CoTTRELL. — Auafomy of Siphniiaria obliquata. 



591 



duct is of small diameter ; it passes forward, and after reaching the pos- 

 terior extremity of the common duct runs across its large posterior region 

 (fig. 6 ; hil). After a sharp bend, which gives rise to a small finger-shaped 

 process [hd'), it enters the posterior end of the common duct, which end 

 is directed forwards owing to the fact that this extreme posterior part of 

 the common duct is bent upon itself. About the middle of its length the 

 hermaphrodite duct dilates somewhat, giving rise to the seminal vesicle, 

 which rests on the posterior end of the common duct (fig. 6 ; sv). The 

 common duct consists of two parts — glandular and non -glandular. (1.) For 

 about half its length the duct is large and very glandular ; this region 

 runs forwards, and, except for the posterior bend mentioned above, is quite 

 straight (fig. 6 ; cd). (2.) The duct then gradually loses its glandular 

 character, and tapers to a tube of comparatively very small diameter ; at 

 the same time it bends sharply on itself twice, and then on reaching the 

 body-wall it bends forward again, running on the left side of the spermo- 

 theca duct towards the penis (fig. 6 ; cd'). At the side of the glandular 

 region of the common duct is the spermotheca, a spherical greyish sac 



supplied with a stout 

 muscular duct which 

 runs forwards with the 

 common duct, both en- 

 tering the penis close 

 together near the geni- 

 tal pore (fig. 6 ; sth, 

 sthd, cd', gp). 



The penis is a large 

 muscular pyriform 

 organ, occupying the 

 anterior region of the 

 body - cavity on the 

 right side of the buccal 

 mass. It opens to the 

 exterior by the genital 

 pore. Distally the 

 penis tapers to a thick- 

 walled muscular tube, 

 which carries at its end 

 the prostate gland 

 (fig. 6 ; p, pro). This 

 gland has a bright- 

 orange colour, while 

 the penis is of a light- 

 cream tint. 



The various lobes of 

 the hermaphrodite 

 gland are made up of 

 follicles. In each lobe 

 there is a somewhat ex- 

 tensive central follicle 

 surrounded by smaller follicles which are outgrowths from its walls 

 (fig. 7 ; c/, ef). From the germinal epithelium of these outer follicles the 

 ova arise, and in section each of these follicles contains one, two, or three 

 ova — seldom more. From the epithelium of the large central follicle the 



Fig. 7.- 



-Hermapheodite Gland (Transverse Section) 

 X 60. 



cf. Central follicle, producing spermatozoa (sp) ; ef, external 

 follicles, producing ova (o) ; ef.d, efferent duct leaving 

 central follicle ; x, passage from external to central 

 follicle. 



