S8 
TORTOISES AND TURTLES. 
This turtle is generally distributed throughout the tropical portions of the 
Atlantic, Indian, and Pacific Oceans, from whence it occasionally wanders 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 molluscs. 
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, upwards 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 
flavour, and is not, therefore, generally eaten. 
Gigantic as is the existing leathery turtle, it was 
considerably exceeded by some of its extinct allies. 
Among these, the huge Eosphargis, from the London Clay, 
with a skull of nearly a foot in length, apparently had a 
carapace consisting only of one median row of broad-keeled bony plates, and a 
border of marginal bones; while in Psephophorus, from the higher Eocene and 
Miocene strata of the Continent, both upper and lower shells were formed of 
mosaic-like bones, which, it is thought, were overlain by horny shields. In the 
earlier Protostega and Protosphargis, from the Cretaceous rocks of North America 
and Europe, the upper shell appears to have been represented merely by a row of 
marginal bones, while the lower one was very stoutly ossified; some of these early 
forms probably attained a length of from 10 to 12 feet. 
The Side-Necked Tortoises. 
Families CllEL YIDSE and Pel omedUSIDsE. 
In place of withdrawing the head into the shell by means of an S-like 
flexure of the neck in a vertical plane, as in all the groups hitherto described, 
the remainder of the living tortoises with complete shells bend the neck side¬ 
ways in a horizontal plane (as shown in the illustration on p. 92), and thus 
bring the head within the margins of the shell. Accordingly, the group is 
collectively spoken of as the side-necked tortoises, or Pleuroclira. This character 
is alone amply sufficient to separate the group from the foregoing assemblage 
FRONT VIEW OF LEFT HUMERUS 
OF AN EXTINCT LEATHERY 
TURTLE. 
