536 MANUAL OF ZOOLOGY. 



are furnished with fleshy lips. All the Trionycidce inhabit fresh water and 

 are carnivorous in their habits. Good examples are found in the Soft- 

 shelled Turtle (Trionyx ferox\ and the large and fierce Snapping Turtle 

 (Chelydra serpentina) of the United States ; but other species are found in 



Fig. 294. Hawk' s-Bill Turtle (Ckelone imbricata) after Bell. 



Egypt and the East Indies. The Terrapins (Etnys] have a horny beak, 

 and have the shield covered with epidermic plates. They are inhabitants 

 of fresh water, and are most of them natives of America. 



The third section of the Chelonia comprises only the Land Tortoises 

 (Testudinida), in which the limbs are adapted for terrestrial progression, 

 and the feet are furnished with short nails. The carapace is strongly con- 

 vex, and is covered by horny epidermic plates ; the head, limbs, and tail 

 can be completely retracted within the carapace. Though capable of 

 swimming, the Tortoises are really terrestrial animals, and are strictly 

 vegetable feeders. The most familiar species is the Testudo Grceca, which 

 is indigenous in Spain, Italy, and Greece. A much larger species is the 

 so-called Indian Tortoise (Testttdo Indica), which inhabits the Seychelles 

 and Galapagos Islands, and attains a length of over three feet. 



DISTRIBUTION OF CHELONIA IN TIME. The earliest-known 

 traces of Chelonians occur in the Permian rocks, in the lower 

 portion, that is, of the New Red Sandstone of older geologists. 

 These traces, however, are not wholly satisfactory, since they 

 consist solely of the footprints of the animal upon the ripple- 

 marked surfaces of the sandstone. Of this nature is the 

 Chelichnus Duncani, described by Sir William Jardine in his 

 classical work on the ' Ichnology ' of Annandale in Dumfries- 

 shire. The earliest unequivocal remains of Cheloniida are in 

 the Oolitic rocks (the Chelone planiceps of the Portland Stone). 



