T. mydas, or the common green turtle, is not unfrequently five feet long, and of the weight of 500 pounds ; and is denomi nated green, from a shade of that colour assumed by the fat when the animal is in its perfect state. In the 'West Indies it has been long in the highest estimation for the table, and within sixty or seventy years it has gradually been advancing in reputation in this country for food, and is at present considered as furnishing the highest
T. imbricata, or the imbricated turtle, or hawksbill, is so called from its shells lapping one over another, like tiles on the roof of a house. It is about three feet
long ; is found in the seas both of Asia and America, and sometimes also in the Mediterranean ; and is said to have been seen even of 600 pounds weight. Its flesh is in no estimation ; but its lamina are manufactured into that elegant material, known by the name of tortoise-shell, which has been applied by human inge nuity to innumerable purposes both of use and ornament. The thickness of the plates varies in reference to the age and size of the turtle. Those of a very young one are of no value. A large one will supply . ten pounds weight of valua ble scales, which being softened by heat, and lapped over each other by means of pressure, become eflectually united, so as to constitute one piece of considerable extent, and without any perceivable trace of their separation. This article was well known to the Greeks and Romans, and was an important material of luxury and commerce. Various articles of furniture, and even beds, were inlaid with it. The Egyptians exported large cargoes of it to Rome for these purposes; and in China, as well as Europe, it is at present in very high demand for elegant and ornamental manufactures.