TURTLES. 157 



Turtles are the largest of their genus : they swim with great faci- 

 lity, and can remain a long time under water. The external orifice 

 of the nasal canal is furnished with a sort of valve, which the animal 

 raises when it is in the air and closes when submerged ; but it rarely 

 leaves the sea except in the breeding season, when Nature prompts it 

 to seek the shore to lay its eggs. Some species, however, frequent 

 the shore in the night, to browse on terrene plants. On land they 

 move with difficulty, and even with pain ; but not so in the sea, where 

 they are remarkably active. Some species feed upon sea-weed and 

 algas, while others prefer living animals, such as crustaceans, zoophytes, 

 and molluscs, which they seize with their horny jaws, which are hard 

 and trenchant as the beak of a bird of prey. 



We have seen how regularly and systematically the Land Tortoises 

 proceed when ready to deposit their eggs; nor is less method adopted 

 by the Turtle. The females, accompanied by the males, frequently 

 traverse hundreds of miles of sea in order to deposit their eggs in 

 some favoured locality, and resort, year after year, with the greatest 

 punctuality, to the same island where they drag themselves ashore 

 sufficiently inland to be safe from the tide. Using their hind flippers 

 as a shovel, they excavate holes about thirty inches deep. Here they 

 lay frequently a hundred eggs, afterwards covering them with sand. 

 Having carefully levelled the surface, they return to sea, leaving the 

 eggs to be hatched by the solar rays. The eggs are round, slightly 

 depressed at both ends, and furnished with a coriaceous shell. 

 From the high temperature communicated to the sand-bank, they are 

 hatched in about fifteen days. The females seem to have two or 

 three layings in the season, at intervals of two or three weeks. When 

 the young turtles are hatched, their instincts lead them at once to 

 the sea ; they are then feeble, white, and about the size of frogs. 

 Under the fostering care of their mother, those which have escaped 

 the birds of prey on their way to the sea and the fishes lying in 

 wait for them, rapidly develop, and attain, under favourable cir- 

 cumstances, an enormous size — some of the Sphargis, or Leathery 

 Turtles, having been known to weigh from 1,500 to 1,600 pounds, 

 — while others, whose carapaces measured more than fifteen feet in 

 circumference and seven feet in length, exceeded 1,800 pounds. 



Turtles are met with in herds more or less numerous in all seas 

 in the tropical regions. The shores of the Antilles, the Gulf of 

 Mexico, and the Indian Ocean, are their favourite haunts. Those 

 occasionally found by navigators in the North Atlantic seem to be 

 stragglers who have wandered from their companions. 



Of all Chelonians, the Turtle is the most useful to man. In 



