CHELONIDAE 38 1 



is almost cosmopolitan within the warmer zones, but not a few 

 iind their way far into the temperate seas. They are all eagerly 

 hvmted by man either for food or for the sake of the tortoise- 

 shell. 



Chelo7ie.—With only four pairs of costal shields. Carapace 

 with large persisting fontanelles between the costal and marginal 

 plates. Two species. 



Ch. mydas (the " Green or Edible Turtle ") has when adult a 

 nearly smooth shell, all the shields being juxtaposed, fitting closely 

 into each other, and becoming quite smooth with age. The 

 neural shields of younger specimens have a feeble keel. The 

 twenty-five shields which surround the carapace form a smooth, or 

 but indistinctly serrated rim. The head is covered with one pair 

 of prefrontal shields, the others are small. The horny beaks of 

 the upper and lower jaws have denticulated outer edges, those of 

 the upper jaw having two pairs of strong denticulated ridges. 

 The limbs have generally only one claw, namely on the first 

 digit. This claw, although sometimes curved and thick, and 

 more than an inch in length, is blunt. The general colour is 

 olive or brown above, with yellowish spots or blotches ; the 

 under parts are pale yellowish. This species attains a large 

 size, with a length of shell of nearly four feet, but the usual 

 length of full-grown specimens is three feet, and these weigh, 

 when in good condition, more than three hundredweight. Their 

 home is in the Atlantic, Indian, and Pacific Oceans, but there 

 are certain regions in which they are more common than in 

 others. Famous centres are the Island of Ascension, the West 

 Indies, and the coast of Mosquito, at least for commercial 

 purposes. As they require sandy, easily accessible beaches for 

 the deposition of their eggs, they congregate in certain parts of the 

 world more than in others, and being strictly vegetable feeders, 

 they are naturally bound to the coasts, although they are some- 

 times met with far out at sea. Their chief food consists of 

 algae, and of Zostera marina, the edible " Dulce," which grows 

 plentifully in the lagoons of the coast of Florida. When they 

 have eaten their fill, they are said to chop off more of these 

 plants, and roll them, together with the adherent mud, into balls 

 of the size of a head, and these balls, receding with the tide, 

 are followed by the Turtles. 



Whilst in the water they are caught in ' various ways, with 



