tortoise (1 as u), tortuce

[O. Fr. tortue (Fr. tortue ), from Low Lat. tortuca, tartuca =a tortoise; O. Ital. tartuga; Ital. tartaruga; Sp. tor. tug a; all from Lat. tort us, pa. par. of torqueo =to twist, from the crooked or twisted feet of the tortoise.] 1. Zool.: A name formerly taken to include all the Chelonians, but now, unle qualified by an adjective, confined to the individuals of the family Testudinide. (TERRAPIN, TURTLE.] Tortoises, in the wider sense, are sluggish reptiles, long-lived, and extremely tenacious of life under adverse surroundings, and have survived from remote antiquity while higher animal types, formerly contemporaneous with them, have become extinct, and have been succeeded by very different forms. They have an o eous exoskeleton, which is combined with the endoskeleton to form a kind of bony case or box in which the body of the animal is inclosed, and which is covered by a coriaceous skin, or, more usually, by horny epidermic plates. [TORTOISESHELL.] The exoskeleton consists e entially of two pieces: a dorsal piece, generally convex (the carapace), and a ventral piece, usually flat or concave (the plastron), by some regarded as an abnormally developed sternum, while others consider the bones of which it is composed as integumentary o ifications. In the endoskeleton the dorsal vertebræ are immovably joined together, and have no transverse proce es, the heads of the ribs uniting directly with the bodies of the vertebræ; the scapular and pelvic arches are placed within the carapace, so that the scapular arch is thus inside the ribs, instead of being, as it normally is, outside them. All the bones of the skull, except the lower jaw and the hyoid bone, are anchylosed. There are no teeth, and the jaws are cased in horn, so as to form a kind of beak. Tongue thick, and fleshy; heart three-chambered, ventricular septum imperfect. The lungs are voluminous, and respiration is effected by swallowing air. All will pa prolonged periods without food, and will live and move for months after the removal of the entire brain. in close order and placing their bucklers over their heads, making a cover resembling a tortoise-shell; a testudo (q. v.). tortoise-beetle, s. Entom.: Any individual of the Ca idide or Ca idiade (q. v.). So named from their form, the body being margined all round with dilatations of the thorax and the elytra. tortoise-encrinite, s. Zoology : The genus Marsupites (q. v.), from presenting some resemblance to a tortoise in their appearance. tortoise-flower, s. [CHELONE, 2.]