Page:The American Cyclopædia (1879) Volume XV.djvu/841

TORTOISE 811 and narrow body, the carapace rising to be- hind the middle, and thence descending steep- ly backward ; the whole shield is ossified, cov- ered with large horny scales, and as wide behind as in front, with a tendency of the edges to round up and turn inward ; the tail is neither long nor strong enough to bear any of the weight of the body, and in the male ends in a horny nail ; legs slender, feet short and round, toes freely movable and webbed, and the whole very flexible ; head long behind and short in front of the eyes, pointed, with Jhe small mouth underneath; alveolar ridge sharp, the lower jaw ending in a point ; neck long and slender ; the plastron is sometimes hinged. In average size they are the smallest of the order, the least being about 4 in. and the largest 9 in. in length ; all are American, and no trace of their fossil existence has been discovered ; the sexes are very different. They live mostly in water and in the mud, coming out to bask in the sun in places where they can readily drop into the water at the ap- proach of danger ; their food is principally animal, and their motions quick, though feeble and awkward ; generally timid, they bite fierce- ly if attacked while feeding, like the insectiv- ora among mammals. The colors are gen- erally dark, sometimes with reddish, greenish, and yellowish tints. They lay three to five eggs, on the shore near the water, in holes dug with their hind feet ; they are elongated, with a smooth and shining surface, thick, and brittle. In the common mud tortoise ((thy- rosternum Pennsyhanicum, Ag.), the jaws are strong and cutting, and the mouth long and narrow ; it is dusky brown above, yellowish dusky or brownish below ; chin and throat dirty yellow, with the warts on the latter brighter ; it is usually about 3 in. long, nearly 3 in. wide, and If in. high. It is found from Pennsylvania to Florida, and west to the Mis- sissippi valley ; the anterior and posterior parts of the sternum are movable on the central piece ; it abounds in muddy ponds, feeding on small fish and aquatic insects and larvae ; it is a pest to anglers, seizing the bait set for bet- ter game ; it has a slight odor of musk, but less so than the musk tortoise (ozotheca odora- ta, Ag.), which ranges from New England to Florida, and west to the Mississippi. The emydoida are most numerous in species, over 60 being described, presenting great differences in size, structure, and habits. The body is ovate, swelling in the centre, the margin with a tendency to spread outward ; the carapace is completely ossified and united by sutures, high and irregularly convex in all directions ; plas- tron long and broad, and sometimes hinged ; the jaws horny, without lips, and not termi- nating in long sharp points; head, neck, and limbs completely retractile ; nostrils at the end of the snout, which is not prolonged into a proboscis ; toes long and webbed, or short and free, according as the habits are aquatic or terrestrial; skin of head, neck, limbs, and tail more or less scaly. They are principally aquatic, though some are terrestrial, the limbs moving horizontally while swimming, and walking being performed on the whole foot (as in plantigrades); they are generally of moderate size, the smallest being 4 in. and the largest (the aquatic) 15 in. in length. The fqod is both animal and vegetable, consisting of fish, worms, larvae, berries, leaves, and grass ; they are most abundant in warm regions. The eggs are laid in holes dug by their hind legs, the terrestrial species laying 2 to 7, and the aquatic 10 to more than 30 ; the shell is less calcareous and more flexible than is usual ; the shape is oblong. Though this family is most numerous in North America, there is not a single species described under the genus emys by herpetologists which belongs in it; the so-called cutudo Blandingii, corresponding to the emys of Europe, is the only representa- tive here of Brongniart's genus ; the others belong to various genera as established by Agassiz in vol. i. of his "Contributions to the Natural History of the United States" (1857). The genera trachemys (Ag.), ptychemys (Ag.), deirochelys (Ag.), and malacoclemmys (Gray) have been described under TERRAPIN. The Shell of the Painted Tortoise (Chrysemys picta). common painted tortoise (cJirysetnys picta, Gray) may be known by the yellow borders of the black dorsal scales, the blood-red blotch- es and lines on the marginal plates, limbs, and under part of tail, and the golden yellow ster- num. It is found as far north as New Bruns- wick, through the eastern and middle states to South Carolina and Georgia; west of the Ohio it is replaced by the C. marginata (Ag.) ; it is about 6 in. long, 4$ in. wide, and 2 in. high ; it is most abundant in ditches and slug- gish waters, spending most of the day basking in the sun ; it is very timid, hibernates early, and is one of the first to appear in spring ; it feeds on insects, worms, tadpoles, &c., and is very troublesome to anglers; "it will survive only a few days out of the water. The speck- led or spotted tortoise (nanemys guttata, Ag.) is another very common species, distinguished by its yellow dots on a black ground, and its blackish sternum bordered with yellow. It is found from New England to the Carolina?,