PELAMYS BICOLOR. 377 



The Water-Snakes [Hydrophida] . 



The animals of this tribe resemble very much in their general ap- 

 pearance a snake, from which they probably received the name of 

 ' Water- Snake :' but they differ, perhaps, as much from the snake, as 

 the water-newt does from the lizard ; and therefore the term lizard to 

 the newt is as applicable to that animal, as that of water- snake to the 

 other. They differ from both of those tribes [lizards and newts] in 

 having only one lung ; but they come nearest to the water-newt in the 

 form of the anus, although not exactly; which part in the newt is 

 very different from either that of the lizard, snake, viper, &c. They 

 partake more of the snake in the parts of generation than of the frog, 

 toad, chameleon, (fee. 



The Water-Snake, with a dark back and yellow belly [Pelamys 

 bicolor, Daud.]. 



It is pretty round near to the head ; but, as it approaches nearer to 

 the tail, it grows flatter and flatter, and at the tail it is extremely thin 

 [from side to side]. Its back, having the bone and muscles for motion 

 in it, is thick ; but towards the belly it becomes thinner, terminating 

 almost in an edge like a knife 1 . The ribs are continued as far as the 

 anus, which preserves this shape. The scales of the skin do not over- 

 lap, tile-form, but are formed into a kind of irregular hexagonal 

 figure, placed in rows. The teeth are like those of a snake. The abdo- 

 minal viscera are united together by cellular membrane, and thereby 

 to the abdomen. The oesophagus and stomach form one straight canal ; 

 the intestine going out at one side of the bottom of the stomach 2 . 



The intestines are folded or coiled on one another, like the vas 

 deferens where it begins to form epididymis ; which folds are united to 

 one another. The liver is only one lobe, placed on the right side ; it 

 is small. The gall-bladder is detached from the liver, lying in the first 

 bend of the first intestine. The duct of the liver passes down from 

 the liver to the intestine • and a duct also passes from the gall-bladder 

 to the intestine about half an inch long. These ducts passed through 

 that end of the pancreas which lies on the intestine. The gall was 



bile from being driven directly into the gut when the liver is pressed upon by the 

 swallowed prey, in course of deglutition. 



The anatomy of the rattle-snake is shown in the Hunterian Preparations, Nos. 

 778, 802, 1091, 1819, 1921, 1922, 2106, 2162, 2419, 2709, 3314, 3315, 3316.] 



1 [They have a poison-fang, with smaller teeth, on each side of the upper jaw, 

 and then* bite is dangerous.] 



2 [Hunt. Prep. Phys. Series, No. 508.] 



