228 Records of the Indian Museum. [Vol. XXII, 



once more and is now continued on as the rectum. It passes 

 forwards on the right of the whorl, lying on the surface ; in the 

 2 it is in close apposition to the albumen- and shell-glands, and 

 passes downwards and forwards immediateh' to the outer side of 

 the kidnej- and the first pprt of the ureter. In the body-whorl it 

 passes forwards, as we have alread}^ seen, in the roof of the 

 branchial chamber and opens at the anus. In this latter part of 

 its course its walls are thrown into numerous transverse folds. The 

 contained faeces are moulded into small oval compact masses. 



The Vascular Systr.m. 



The heart lies in the pericardial chamber at the apex of the 

 bvanchitl cavity and on the inner side of the penultimate body- 

 whorl. It is a closed cavity the walls of which are in places 

 exttemely thin and delicate and hence are very liable to become 

 torn or ruptured. On its inner aspect the pericardium is separated 

 from the shell only by thin membrane; above and in front 

 it is bounded by the kidney, and above and behind is the loop of 

 the intestine and the liver ; on its right or outer side lie the 

 genitalia and the rectum ; while below it lie the oesophagus, the 

 termination of the supra-intestinal and sub-intestinal nerves and 

 the splanchnic ganglion and, in the female, the loop of the oviduct. 

 On its outer and upper aspect the cavity of the pericardium com- 

 municates with the kidney through the reno-pericardial opening, 

 the position of which will be studied when dealing with the kidnev 

 itself. 



The heart consists of two chambers. Anteriorly is the soft- 

 walled whitish-looking auricle, the walls of which are usually 

 thrown into a series of irregular folds. In almost every adult 

 example examined, the auricular wall was seen to contain a 

 number of small round white bodies. These are cysts of an 

 Echinostome Agamodistome and are present in such large num- 

 bers that they may almost fill the whole org-in. The wall 

 of the auricle is thick and glandular, and is said to form 

 the haematic gland that is present in other molluscs {vide 

 Perrier, 1889, p. 178). The ventricle hes posteriorly and is a 

 rounded body of a pale brownish colour and its walls are thick 

 and muscular. The auriculo-ventricular aperture is tube-like and 

 projects into the cavity of the ventricle. From the inferior aspect 

 of the ventricle arises a short wide aorta. In Vivipara vivipara 

 (vide Perrier, 1889, pi. viii, fig. 38 x.) there is said to be a valve- 

 like flap at the point of origin of the aorta from the ventricle, 

 which prevents the regurgitation of blood during the ventricular 

 diastole. Leydig (1850, p. 170) on the other hand states that there 

 is a cresentic valve situated between the auricle and ventricle. 

 In Vivipara bengalensis I have failed to find any indication of 

 eith("r. The common aorta almost at once bifurcates into two 

 wide trunks, which run in opposite directions. One branch, the 

 cephalic aorta, passes forwards and downwards to the inner side of 

 and close to the oesophagus. In this position it passes forwards 



