240 SNAKES. 



A further facility to their agile and graceful Natural size, 

 movements in the water are their smooth, non- 

 imbricated, or only slightly imbricated scales. 

 These, though mostly hexagonal, and laid side 

 by side, different from those of land snakes, 

 yet vary much in size and form ; and the head 

 shields particularly are so abnormal, that, as 

 Giinther affirms, you can tell a sea snake at 



Same magnified. 



once by them (see illustrations, chap, xviii.). ^ , . i 



To distinguish a pelagic from a fresh-water ^"""""ofhidJa"""'' 

 snake is, however, far easier than to distinguish species 

 among themselves. They present great varieties of form 

 and colour, but the transitions are very gradual, and the 

 female is generally larger than the male, and sometimes of 

 a different colour, which adds to the difficulty. 



They are all viviparous, and produce their young in the 

 water, where the little ones are at once able to take care 

 of themselves, and feed on small fish or molluscs. The 

 full-grown HydropJiidcE feed on fish corresponding with their 

 own dimensions, and swallowed head foremost. Even spiny 

 fish are managed by them, notwithstanding that they have 

 a smaller jaw than most land snakes. Being killed by the 

 poison of the bite on being caught, Giinther explains, the 

 muscles of the fish are relaxed, and the prey being com- 

 menced at the head, the armature does not interfere, but 

 folds back fiat as the fish is gradually drawn into the jaws. 



An interesting study to the lover of nature it is to watch 

 the wonderful movements of these sea reptiles. Swimming 

 and diving with equal facility, flashing into sight and dis- 

 appearing again in twos or scores, or in large shoals, 



