212 OP SERPENTS. 



give the animal great strength and agility in all its motions. 

 The skin also contributes to its motions, being composed of 

 a number of scales, united to each other by a transparent 

 membrane, which grows harder as it grows older, until the 

 animal changes, which is generally done twice a year. This 

 cover then bursts near the head, and the serpent creeps from 

 it, by an undulatory motion, in a new skin, much more vivid 

 than the former. If the old slough be then viewed, every 

 scale will be distinctly seen, like a piece of net-work, and will 

 be found greatest where the part of the body they covered 

 was largest. 



There is much geometrical neatness in the disposal of the 

 serpent's scales, for assisting the animal's sinuous motion.- 

 As the edges of the foremost scales lie over the ends of their 

 following scales, so those edges, when the scales are erected, 

 which the animal has a power of doing in a small degree, 

 catch in the ground, and so promote and facilitate the animal's 

 progressive motion. The erecting these scales is by means 

 of a multitude of distinct muscles, with which each is sup- 

 plied, and one end of which is tacked each to the middle of 

 the foregoing. 



When we come to compare serpents with each other, the 

 first great distinction appears in their size ; no other tribe of 

 animals differing so widely in this particular. 



Leguat assures us, that he saw one in Java, that was fifty 

 feet long. Carli mentions their growing to above forty feet : 

 and we have now the skin of one in the museum, that mea- 

 sures thirty-two. Mr. Went worth, who had large concerns 

 in the Berbices in America, assures me, that, in that country, 

 they grow to an enormous length. He one day sent out a 

 soldier, with an Indian, to kill wild fowl for the table ; and 

 they accordingly went some miles from the fort ; in pursuing 

 their game, the Indian, who generally marched before, be- 

 ginning to tire, went to rest himself upon the fallen trunk of 

 a tree, as he supposed it to be ; but when he was just going 

 to sit down, the enormous monster began to move, and the 

 poor savage perceiving that he had approached aLiboya, the 



