192 1.] N. Annandale «& R. B. S. Sewei^l ; Vivipara. 



223 



to the mantle margin in the angle formed by the roof and floor of 

 the cavity opposite the S5'phon, so that all excreta are at once 

 carried out of the chamber away from the body. 



In the female the uterus and ureter open close together. 

 These two ducts run down side by side on the extreme right of the 

 branchial cavity, the ureter being to the left of the uterus, and 

 the rectum lying above and to the inner side of the ureter. The 

 terminal portion of the uterus is known as the vagina : it forms a 

 prominent rounded papilla, the walls of which are thick and 

 spongy, and the orifice is situated at its apex. This orifice is 

 extremely distensile and in the contracted condition is oval or 

 slit-like. The aperture of the ureter lies above and to the outer 

 side of the vagina. It is much smaller and is provided with a 

 sphincter muscle. The rectum passes down above and to the 

 inner side of the ureter, it ii continued further forward, towards 



ves Senv. 



Fig. 4. — Vivipara beiigalensis, view of the right half of the buccal cavity, 

 cut in the sagittal plane, be. buccal cavity ; br.f. branchial fold ; /./., lateral 

 chitinous jaw ; m., mouth aperture ; od., odontophore ; oes., oesophagus ; rad.s., 

 radularsac; <;y,, transverse fold above and behind odontophore; ves.sem., vesicula 

 seminalis cut in oblique section. 



the mantle margin than either the uterus or ureter and having 

 passed the terminations of these ducts it bends downwards and to 

 the right and opens at the tip of the anal papilla. The terminal 

 papilla and orifice of the anus is usually of a bright golden-yellow 

 colour. 



In the male, the rectum and ureter occupy the relative 

 positions as given above, but the position of the uterus is now 

 occupied by the orange yellow testis. 



The Alimentary System. 



The mouth is situated ventrally at the anterior end of the 

 snout and forms an oval aperture, bounded by fleshy lips, between 

 which the radula is thrust out during the process of feeding with 

 a rotar)' motion from above downwards. The mouth leads back- 

 wards and upwards into the cavity of the buccal mass and 

 each lateral wall is furnished with a low ridge, running from above 



