CHELONID.E, OR TURTLES. 54? 



Marine Tortoises, CHELONIDJE, or Turtles, are at once distin- 

 guished by the compressed and paddle-like form of the feet ; of 

 these, the anterior pair is most developed ; and they are used as 

 oars, or rather as aquatic wings, by means of which these ani- 

 mals can move through the water in any direction, with con- 

 siderable rapidity and address. This conformation, however, 

 renders their progression on land so much the more difficult ; 

 they can only shuffle along at a slow rate and with laborious 

 efforts ; and, from the flattened form of their carapace, they are 

 unable to recover their natural position, when turned upon their 

 backs upon a flat surface. The jaws of the Turtles are robust ; 

 and the upper mandible is received into a groove in the lower, so 

 that their grasp is very firm. Most of the species feed upon 

 marine plants; but the Hawksbill (Fig. 318), so named from the 

 peculiar hooked form of the end of the upper mandible, also eats 

 Crustacea, Shell-fish, Echini, &c. These animals are found in 

 all the seas of warm climates, but principally in the tropical 

 ocean ; though stragglers occasionally arrive at our own shores. 

 They have their favourite breeding-places, to which thousands 

 periodically resort, often travelling thither from immense dis- 

 tances ; these are usually islands situated in the midst of the open 

 ocean, such as the island of Ascension, which is one of those 



most frequented by them. At 

 other times they are found at the 

 distance of many hundred leagues 

 from any land. The species most 

 valued as food is the Chelonia 

 midas, or Green Turtle; this oc- 

 casionally attains an enormous size, 

 measuring six or seven feet in 

 length, and weighing from five to 

 eight hundred pounds; its ordin- 

 ary bulk, however, is much less. 

 The Chelonia imbricata, or 

 Hawksbill Turtle, is the one most 

 no. 318-HAWKSBiLL TURTLE. i n re q ue st for its covering of horny 

 plates, which are known as tortoise-shell; these plates are of 



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