CROCODILES. 307 



her of articulated horny rings, and terminating in a sort 

 of button. By agitating this the rattlesnake produces a 

 noise much like that of the locust, this noise being usually 

 made when the snake is excited. The number of rings 

 is increased with successive sloughings or castings of the 

 skin, but does not indicate the age of the animal. There 

 are three other poisonous serpents in the United States : 

 the water moccason and the small harlequin snake of the 

 South, and the copperhead, so called from its coppery 

 color, of the North. 



Among the poisonous snakes of other countries the 

 better known are the cobra of India, whose bite causes 

 large numbers of deaths annually, the puff adder of 

 Southern Africa, and the fer de lance of Martinique. 

 The stings of venomous serpents rapidly paralyze the 

 nerve-centres, and depress the circulatory and respira- 

 tory functions ; at the same time there is great local and 

 general swelling of the affected part and its vicinity. 



CROCODILIA. 



Crocodiles grow to a large size. Their bodies are pro- 

 tected by a hard scaly hide, which is almost impenetrable 

 by bullets. Their diet is carnivorous, their life aquatic ; 

 they cannot walk well on shore, their bodies being too 

 heavy for the legs, but they swim very rapidly. The 

 larger species are dangerous to man, the crocodile of 

 the Nile being said to attain a length of thirty feet, 

 although those seen are not often more than half that 

 long. The ancient Egyptians worshipped them. 



The alligators have shorter and broader heads than 

 the crocodiles, and are not so large, the greatest length 

 being about twenty feet. They are found in the waters 

 of South America, Mexico, and the Southern United 



