220 



Records of ths Indian. Museum. [Vol. XXII, 



prs. 



ntestine ; k.. 



margin show- 



osphradiuin ; 



, rectum ; st , 



//.. upper and 



branchial roof, running obliquely forward from left to right, is the 

 line of attachment of the gill, and close to it in front and to the 



left and extending back 

 for only a comparatively 

 short distance from the 

 mantle margin is an opa- 

 que whitish- yellow narrow 

 streak, which denotes the 

 position of the osphradi- 

 um, while extending for 

 the whole distance along 

 its right and posterior 

 border is a brown band, 

 the branchial gland. On 

 the extreme right of the 

 branchial cavitj" in the 

 a- is the crescentic spi- 

 rally-twisted testis, which 

 is usually of a bright yel- 

 low or orange colour, 

 though this character is 

 often obscured by the 

 dense black pigmentation 

 of the skin ; in the 9 

 this position is occupied by 

 the thin-walled distended 

 uterus, which seems invariably to contain eggs and young in the 

 sexually mature examples, no matter at what season of the j-ear 

 they are taken. To the left of the uterus is a narrow clear line 

 which denotes the course of the ureter, and bej'ond this again is a 

 broad brownish band, indicating the course of the rectum. The 

 central portion of the roof of the branchial chamber is thin- 

 walled and is traversed by numerous blood-sinuses which com- 

 mence in the perirectal sinus on the right and pass transversely 

 across to the left to open into the afiferent gill vein which runs 

 along the course of the branchial gland. The free edge of the 

 mantle underlies the peristome of the shell, and is thickened and 

 covered with ciliated epithelium. In young specimens it is 

 produced into a series of IMunt finger-like processes, which are 

 usually of a golden-j^ellow colour {vide infra). These tend to 

 disappear as age advances, but traces of them can still be made out 

 in the adult. There is often a quite noticeable one situated on 

 the mantle margin opposite the commencement of the gill, and the 

 yellow pigment-splashes on the mantle margin' possibly denote the 

 former positions of others that have .since disappeared. 



Immediath^ behind the free edge of the mantle, running 

 parallel to it, is the shell-gland. This is most highly developed, as 

 one would naturally expect, during early life, when the rate of 

 growth is most rapid. A similar band exists in Vivipara vivipara 

 and has been noticed by Villepoix (1895, p. 513). I,aterally the 



Fig. 3. — Vivipara bengulensis : view of the 

 visceral hump from abo\e. of. g.v., afferent 

 gill vein; alb.g., albumen gland; e.s.g., esfa- 

 shell gland ; gb.. gill base ; iiit. 

 kidne)' ; /., liver ; mm., mantle 

 ing traces of processes ; ospli 

 pr.s., perirectal blood sinus ■ ;■ 

 superficial area of stomach ; 11. 

 lower parts of uterus. 



