82 
TORTOISES AND TURTLES. 
structure; while the limbs form most perfect paddles, capable of propelling the 
animals with great speed. The head is placed upon the neck in such a manner as 
to allow of the nostrils being readily raised above the surface of the water for the 
purpose of breathing, and the nostrils themselves can be hermetically closed by 
means of a fleshy valve. The three best known species of turtles, which are 
assigned to two genera, are inhabitants of all tropical and subtropical seas; one 
species—the loggerhead—occurring in the Mediterranean, and occasionally wander¬ 
ing northwards. 
Green Turtle. 
Widely celebrated as being the source of the far-famed turtle- 
soup of civic banquets, the green turtle (Chelone mydas ) is one of two 
species belonging to a genus characterised by the presence of four pairs of costal 
shields on the carapace, and by the persistence of the vacuities between the costal 
and marginal bones of the latter 
throughout life. The plastron 
is, moreover, distinguished by 
the presence of an intergular 
shield between the two gulars; 
while, as in the second genus, 
there is a row of inframarginal 
shields between the marginals 
and the proper shields of the 
plastron. The skull is of moder¬ 
ate size in comparison to the shell, 
with the sockets of the eyes 
placed nearly vertically, and 
separated by a broad bar of 
bone. Such are the characters 
common to the two species of the 
typical genus of the family. 
The green turtle is specially 
distinguished by its short beak, 
which is devoid of a hook at the 
tip, and by the shields of the 
carapace being in contact by 
their edges all through life. In 
the young, the carapace shows a faint median keel; while its hinder margin is at 
most but feebly serrated at all ages. Generally there is but a single claw on each 
paddle, although, in some instances, young specimens also have a claw on the 
second digit. In colour, the shell of the adult is olive or brown, with yellowish 
spots or marblings; while in the young it is uniform dark brown or olive above, 
and yellow beneath, the limbs being bordered with yellow on the upper surface, 
and inferiorly yellow with a brown spot near the extremity. The food of the 
species consists of seaweeds, especially the seawrack, upon which the turtles 
graze at the bottom of the water, rising occasionally to the surface to breathe. 
Generally rejected as food, the hawksbill turtle ( C. imbricata ) 
iia-WKSDiii lurtie. , _ t 
enjoys thereby no respite from persecution, since it is eagerly hunted 
GREEN TURTLE. 
