110 DR. A. GUNTHER ON THE ANATOMY OF MONITOR. [Mar. 26, 



The pharynx and the upper parts of the oesophagus are not black, 

 as in Regenia and other Varani. The oesophagus is provided with 

 numerous low longitudinal folds, and passes without distinct separa- 

 tion into the long, pad-like stomach. Its mucous membrane is very 

 thick, and forms irregular thick folds, anastomosing with one another, 

 and chiefly running in a longitudinal direction. Its muscular mem- 

 brane has a tendinous appearance, and becomes thicker in the pyloric 

 region, the width of a vertical cut being two lines and a half ; there 

 is, besides, a longitudinal tendinous, pad-like protuberance on each 

 side of the pyloric extremity. The whole structure distinctly shows 

 that this is a true pylorus, and that the part behind it belongs to the 

 intestinal tract*. This commencement of the intestine, which is 

 nearly the same as in Regenia, and which we have called there a 

 duodenum, is 20 lines long, not wider than, and separated from, the 

 small intestine by a circular valve, which is 1^ line deep. The en- 

 trance of the ductus choledochus is 15 lines below that valve. The 

 valvulae conniventes run in an oblique direction from the mesenterial 

 line towards the side opposite, parallel to one another, and always a 

 higher alternating with a lower one ; they are provided with numerous 

 delicate villi. The valvulae become deeper, less oblique, and more 

 transverse in the posterior portion of the jejunum ; and the villi here 

 are coarser and more numerous. The jejunum passes into the ilium 

 or into the portion without valvulse, quite suddenly. This portion is 

 wider than the jejunum, and provided with Peyerian glands, which 

 are less numerous than in Regenia, and less distinct ; so that perhaps 

 they might have escaped my observation, if my attention had not 

 been previously directed to them by their occurrence in R. ocellata. 

 The passage into the wide rectum is narrow, and without a valve 

 behind. The cloaca is separated from the rectum by a broad fold 

 of the mucous membrane. 



The length of the stomach is 5 lines, of the jejunum 21, of the 

 ilium 1 1, and of the rectum with the cloaca 5. 



The liver is large, divided by a comparatively small notch into a 

 right and left lobe ; both are depressed, elongato- ovate, and the right 

 one is nearly twice the size of the left one, having a small elongate 

 lobule appended at its posterior part. The gall-bladder is round, of 

 moderate size, and partially imbedded in the substance of the liver. 



The heart is situated as in Regenia. The separation of the two 

 atria is complete, and the right one is rather larger than the left ; 

 both are provided with trabeculse carneae. The right atrium receives 

 the blood from two vense cavse superiores (externa et interna) and 

 from a very large vena cava inferior ; the circumference of the former 

 is 8 and 9 lines, of the latter 16 ; the vena cava superior interna, 

 however, has a considerably narrower lumen where it enters the 

 atrium than in the part next above. All the three vense enter the 

 atrium at the same spot from behind, near the septum atriorum. 

 The directions of the currents of blood are such that that from the 



* A similar division of the intestinal tract, found in the Crocodiles, is described 

 as a part of the stomach (Stann. & Sieb. ii. p. 110), and, as we think, with better 

 right, that division being much wider than the small intestine. 



