While most of the Tortoises are highly useful to man, both for food and other purposes, perhaps the most interesting are the Green Turtles (_Tortues franches_ of French authors), _Chelonia caouana_ and _Caretta_. From these man draws the greatest advantage from their superior size, and from the thickness of their shells. The Green Turtle (_Chelonia Mydas_, Fig. 40) is so called from the reflected green of its carapace. It abounds in the Southern Atlantic Ocean, where it keeps habitually far from the shore, except in the breeding seasons, when it makes long voyages in order to deposit its eggs, giving a preference for that purpose to Ascension Island and St. Vincent. It rests on the surface of the open sea, and as it sleeps heavily, it is easily taken by a cord with a running knot, which is carefully slipped round its neck as the boat containing the captors silently glides past. It is even said to be a practice with the Malay fishermen to dive beneath them, and attaching a cord to the foot of a sleeping Turtle, thus take it alive. Many other modes are employed for capturing them. In the regions frequented by them in the breeding season, they are followed by their track on the sands, and their retreat cut off, when met with, by forming a circle round them, when they are thrown on their backs; hand-spikes sometimes being necessary to accomplish this from their great size. In this position they are helpless, and must remain until wanted, so that their enemies have time to pursue their sport elsewhere, as represented in Fig. 41. The next day they are collected or destroyed at leisure. In 1802 the crew of a French ship surprised a female Turtle on the Island of Lobos. The men had infinite trouble in making good its capture and throwing it on its back, for it was strong enough to drag them all towards the sea. It was at last mastered. Its head was as large as that of an infant, and its beak four times the size of a paroquet. It weighed two hundred and sixty pounds, and had in its body three hundred and forty-seven eggs. Turtles are also taken in nets, in the meshes of which their beaks and flippers get entangled; thus prevented from coming to the surface for air, they die of asphyxia. Others harpoon them on the open sea when they come to the surface to breathe. The harpoon is attached to a cord, by which the animal is soon brought to the surface and drawn into the boat. But the commonest mode of capture is approaching them in a boat as they float asleep on the surface--this must be done silently. When within reach, a back flipper is laid hold of by one of the crew, and by a sudden twist the Turtle is thrown on its back, when becoming helpless for the moment, it is dragged on board. [Illustration: Fig. 42.--Hawk's-bill Turtle (_Chelonia caretta_).]