2i8 CHARACTERS OF VERTEBRATE ANIMALS 



forms included in the same genus with the Grecian Tortoise are 

 fourteen giant species, which either are or have been within the 

 last 300 years inhabitants of some of the islands in the Indian 

 and South Pacific Oceans. Of these probably the best known, 

 are those found in the Galapagos Islands off the north-east coast 

 of South America. Several species have been described, one 

 of which {Testudo nigrita) was described by Darwin as reaching 

 such large dimensions that large specimens could only be lifted 

 by from six to eight men. 



The European Pond - Tortoise {Emys orbicularis) may be 

 mentioned as a good example of a fresh-water form. In ac- 

 cordance with its aquatic habits, the shell is much flatter than 

 in a land tortoise, and the feet are webbed. It is a native of 

 South Europe, South-west Asia, and parts of North Africa. 

 Specimens, mostly of small size, are often exhibited for sale in 

 this country. 



(b) Turtles are marine Chelonia obviously adapted for aquatic 

 life, as may be seen from their flattened shells and paddle-like 

 limbs, the digits of which have for the most part lost their claws. 

 The front end of the carapace is notched, and the head can 

 be only partly retracted. The true turtles somewhat resemble 

 the Leathery Turtles (se.e p. 217) in form, a result of adaptation 

 to the same sort of life, but, unlike the latter, the shell is covered 

 by horny plates, and some of the digits have retained their claws. 

 There are also important differences as regards the plastron and 

 carapace. The former, though not so complete as in the Grecian 

 Tortoise, is more so than in the Leathery Turtle, while the 

 carapace is made up of the same elements as in the tortoise 

 and is firmly connected with the internal skeleton. Two species 

 may be noted here — the Green Turtle and the Hawk's-bill 

 Turtle. 



The Green Turtle {Chelone midas), found in all the warmer 

 parts of the ocean, is the species which has attained a doubtful 

 sort of fame in connection with aldermanic feasts. Its short 

 beak devoid of a hook is well adapted for biting off the pieces 

 of sea-weed which constitute the food. The horny plates which 

 cover the carapace are united by their edges. 



The Hawk's-bill Turtle {Chelone imbricatd) has the same 

 wide distribution as the preceding species, but is somewhat 

 smaller. Its strongly-hooked beak accords with a carnivorous 



