BRANCH CHORD AT A: CLASS REP Jill A 3 2 5 



spine or horn, from which the name horned viper is 

 derived. The most poisonous snake of South Africa is 

 the large and ugly puff-adder, which puffs itself up when 

 irritated. An interesting group of snakes is that of the 

 Hydrophidse or sea-snakes, which swim on the surface of 

 the ocean by means of their flattened and oar-like tails. 

 These forms live in the tropical portions of the Indian and 

 Pacific oceans, ranging as far north as the Gulf of Cali- 

 fornia, and spend their whole life in the water, "out of 

 which they appear to be blind and soon die." They are 

 extremely venomous, but are all of small size, rarely two 

 feet long. 



Crocodiles and alligators (Crocodilia) . The crocodiles 

 and alligators are reptiles familiar by name and appear- 

 ance, though seen in nature only by inhabitants or visitors 

 in tropical and semitropical lands. In the United States 

 there are two species of these great reptiles, the American 

 crocodile (Crocodilns americanus], living in the West 

 Indies and South America and occasionally found in 

 Florida, and the American alligator (Alligator missis- 

 sippiensis)^ common in the morasses and stagnant pools 

 of the southern States. The alligator differs from the 

 crocodiles in having a broader snout. It is rarely more 

 than twelve feet long. The best-known crocodile is the 

 Nile crocodile, which is not limited to the Nile, but is 

 found throughout Africa. In the Ganges of India is 

 found another member of this group. of reptiles called the 

 gavial. It is among the largest of the order, reaching a 

 length of twenty feet. The crocodiles, alligators, and 

 gavials comprise not more than a score of species 

 altogether, but because of their wide distribution, great 

 size, and carnivorous habits they are among the most 

 conspicuous of the larger living animals. They live mostly 

 in the water, going on land to sun themselves or to lay 

 their eggs. They move very quickly and swiftly in water 



