LEATHERY TURTLES 



2445 



a gradual disintegration and breaking up of the carapace. In the living genus the 

 carapace is completely bony, and marked by seven prominent longitudinal keels; but 

 the plastron is much less fully ossified, and carries five similar keels, the unpaired 

 entoplastral bone being wanting. The head, which is covered with small shields, 

 is remarkable for its relatively-large size and globose form, the beak having two 

 triangular cusps situated between three deep notches. The jaws differ from those 

 of the true turtles in being sharp edged from end to end, without any expanded 

 bony palate; and there is also an important difference in the structure of the skull 

 itself, which may, however, be apparently the result of specialization. As in the 

 true turtles, the limbs are converted into flattened paddles, which are, however, 

 completely destitute of claws, the front pair being much elongated, narrow, and 

 pointed, while the hinder ones are short and truncated. The humerus, or bone of 

 the upper arm, has the same general form as in the true turtles, and is thus very 

 unlike the corresponding bone of other members of the order. The process marked 

 .h in the accompanying figure is more developed than in the turtles, and the foramen e 

 at the lower end is unique in the order. Largest of living turtles, the leathery 

 turtle exceeds six feet in length; and while in the young the front flippers are equal 

 in length to the shell, in the adult they become shorter. The general color is dark 

 brown, which may be either uniform, or relieved with yellow spots; the longitu- 

 dinal tuberculated keels on the shell, as well as the margins of the limbs, being 

 invariably yellow in the young. 



This turtle is generally distributed throughout the tropical portions of the 

 Atlantic, Indian, and Pacific Oceans, from whence it occasionally \yanders to the 

 coasts of cooler regions. Yearly becoming scarcer, it is, 

 however, one of those species which stand a fair chance of 

 extermination at no very distant date. Although but little 

 is known as to the mode of life of this turtle, it appears 

 that its food is chiefly of an animal nature, comprising 

 fish, crustaceans, and mollusks. In the breeding season it 

 appears in numbers on the Tortugas islands, off the coast 

 of Florida, and sometimes in still greater abundance on 

 the sandy shores of Brazil. Arriving somewhat later than 

 the true turtles, it deposits its eggs in a similar manner, 

 laying as many as three hundred and fifty in two batches; 

 while at times, when three or more females have a nest in 

 common, upward of a thousand eggs may be found in 

 a single spot. When hatched, the young turtles immedi- 

 ately seek the water, where, however, they have almost 

 as many foes as on land; so that it is probable only a 

 very small percentage arrive at maturity. The strength 

 and weight of a full-grown individual are very great; one 

 captured some years ago, on the coast of Tenasserim, 

 requiring the combined efforts of ten or twelve men to 



drag it on to the beach. The flesh has an unpleasant flavor, and is not, there- 

 fore, generally eaten. 



FRONT VIEW OF LEFT HU- 

 MERUS OF AN EXTINCT 

 LEATHERY TURTLE. 



