362 GENERAL ZOOLOGY 



Some snakes produce eggs with a tough shell, others bring 

 forth living young. Some water snakes (Natrix) and garter 

 snakes (Tham'nophis) give birth to large families. As many 

 as seventy-five young may be given birth at one time by a 

 female garter snake. The old superstition that snakes 

 swallow their young to protect them is absolutely false. It 

 probably had its origin in the fact that unborn young are 

 sometimes found in the bodies of dead snakes. 



Turtles and Tortoises. The turtles and tortoises, Chelo'nia 

 (Gr. chelone, ' tortoise "), are externally the best protected 

 of all the reptiles, being incased in a shell formed of plates 

 firmly fixed to the vertebras and ribs. Chelonians have no 

 teeth, but the rim of the jaws is covered with a horny skin. 

 The limbs are sometimes modified into flippers for locomo- 

 tion in the water, though the land and fresh-water species 

 have digits with claws. 



The green turtle (Chelo'nia my'das) of the warmer por- 

 tion of the Atlantic, Indian, and Pacific oceans and the 

 hawkbill (Eretmoch'elys imbrica'ta), also widely distributed 

 in warm ocean waters, are economically important, — the 

 first as an article of food, the second as the source of tortoise 

 shell. These turtles lay their eggs in immense numbers on 

 sandy beaches in holes dug for the purpose by the female. 

 As many as two hundred eggs may be laid by a single female. 

 Within about six weeks they hatch, having been incubated 

 by the heat of the sun. These turtles are captured by the 

 natives of different parts of the world, by diving or by nets 

 or harpoons. A peculiar method of capturing them is fol- 

 lowed by natives of such widely separated regions as Torres 

 Strait, Madagascar, and Cuba. This method consists in 

 utilizing the services of the sucking fish. This fish is pro- 

 vided with a sucker-like attachment on the top of the head. 

 It is borne from place to place by larger fishes, especially 

 sharks and swordfishes, leaving its host occasionally to 



