XV111 INTRODUCTION. 



siderable rapidity ; whilst the marine Turtles have them 

 modified into true paddles, the toes being entirely conceal- 

 ed by hard scaled skin. These modifications of form are 

 very interesting, as evincing an admirable adaptation of a 

 general plan of structure to the varied habits of the dif- 

 ferent groups. 



The jaws of all these different forms are covered with a 

 hard, sharp, horny beak, the lower portion of which shuts 

 within the upper, and the portions of food are cut or 

 snapped off, as it were, on the principle of shears. The 

 aquatic species aid the separation of their food, which they 

 seize with their jaws, by tearing it by means of their long 

 and sharp claws. They thus pursue, seize, and tear in 

 pieces living frogs, and other aquatic reptiles, fish, and even 

 young water birds ; and so forcible and violent is their 

 bite, that I have known a stick of half an inch in diameter 

 at once snapped asunder by the jaws of a snapping Turtle, 

 Chelydra serpentina ; and a specimen of Trionyx, lately in 

 the possession of Mr. Cross, of the Surrey Zoological Gar- 

 dens, snapped off the finger of a sailor when on his voyage 

 to this country. 



The whole of the Testudinata are strictly oviparous, and 

 the egg is covered by a calcareous shell, like that of birds ; 

 the eggs of the land Tortoises, as well as those of the 

 marine Turtles, are generally round ; but those of the 

 fresh-water genera are usually more or less oval or ellip- 

 tical. The multitudes of fresh-water Tortoises in some 

 districts is astonishingly great, and their eggs form a 

 lucrative article of commerce from the quantity of oil which 

 is obtained from them. 



It has been already stated that we have no indigenous 

 species of this order. There are, however, on record seve- 

 ral well-authenticated instances of marine Turtles, of two 



