44 THE STORY OF REPTILE LIFE. 



the expense of the fore, so that these became id 

 time reduced to the merest vestiges. 



Ill-fitted as they are for a life ashore, yet the 

 females, at any rate, are obliged to sojourn here 

 awhile, at least once a year, when they come tq 

 deposit their eggs. Other aquatic reptiles, such 

 as the ancient Plesiosauria and Ichthyosauria.; 

 seem to have avoided this necessity by retaining! 

 the eggs within the body until they hatched j 

 that is to say, they were viviparus. 



Gigantic as some of the tortoises have become, I 

 they are surpassed by their sea-dwelling cousin* 

 the turtles, the species known as the Leathery! 

 Turtle, sometimes weighing as much as a ton.j 

 This animal, however, is like other giant forms, 

 verging on extinction. We shall see indeed as] 

 we proceed how often Nirvana has been achieved! 

 by the reptile-people through the gateway oil 

 over-growth. 



The Green-turtle or " edible-Turtle " (CMonA 

 my das), and the Hawks-bill Turtle (Chelone imbril 

 cata), in so far as the general shape of the body! 

 and paddles is concerned, are extremely like the! 

 Leathery Turtle just described, yet, as has been! 

 pointed out earlier in this chapter, they are only! 

 in a very remote degree related their similarity! 

 is due to what is called " convergence of de- 

 velopment," and not to community of descent. 

 It is this same convergence, this adaptation to 

 environment, which has produced the community 

 of likeness, which has been pointed out between 

 such widely different forms as the turtle, the fish- 

 lizards, and the whales. 



The Green-turtle is the species which plays 



