Tortoise, or Testudo, L. a genus of amphibious animals, comprehending thirty-three species, of which the following are the principal :
1. The midas. See Common Turtle.
2. The imbricata, v. caretta, or hawk's bill tortoise, is a native of South America ; where it attains the length of three feet: its shell is divided into the upper part, which covers the back; and the lower, for the protection of the belly: it is composed of thirteen leaves, or scales, that form the beautiful transparent substance, known under the name of tortoise-shell.
3. The orbicularis, or common river-turtle, inhabits the milder climates of Europe, particularly the swampy parts of Hungary and Sclavonia ; its size seldom exceeding eight or nine, inches in diameter. It is coveted with a smooth dark shell; lives in morasses; and spends the winter under ground, in a torpid state. - The flesh of this species is much esteemed on the Continent, where it is eaten by the consumptive and debilitated, on account of its restorative properties.
Turtles live on worms, inserts, small fishes, and marine plants ; they are reputed for their longevity, subsisting for twelve months on simple water, and evincing mus-cular action, after the head has been severed for a fortnight. Their progress through life is remarkably slow.
The best tortoise-shell pays, on importation, Is. 4 1/2d. per lb. : it is thick, transparent, of a deep lead-colour, resembling that of antimony, and is sprinkled with brown and white spots. Like horn, this shell becomes soft in a moderate beat, and is then manufactured into combs, and other articles, which may be easily stained of different colours, by tinctures made of the common dyeing drugs in spirit of wine; or by the solutions of various metals in the mineral acids.