Another large and valuable turtle is the hawksbill (q.v.), which furnishes tortoise-shell (q.v.). A third species is the loggerhead (Thal assochelys caretta), which is much more fre quently taken on the coast of the Middle and New England States than either of the others. It may be distinguished from the green turtle by the thin non-imbricated plates of the carapace, by having the central scale on the top of the head surrounded by a circle of more than 12 small scales, while the green turtle has seven; and by having two, instead of one, claws on the feet. This species reaches a large size, up to 500 pounds, and is carnivorous. It has no com mercial value, hut is sometimes sold as the green turtle.
A strictly American family (Chelydridee) is that of the snapping-turtles (q.v.), including two well-known species of some commercial importance.
Numerous species of small or medium-sized pond, swamp and land tortoises belong to the families and Emyider. Of the first the well-known musk-turtle or stink-pot of boys (Aromachelys odoratus), found in every pond in the Eastern States, is an example. The diamond-back (q.v.) (Malaclemmys centrata) of the Atlantic salt-marshes, the red-bellied ter rapin (Pseudemys rubriventris), the .painted turtle (Chrysemys pieta) and the speckled tor toise (Clemmys guttatus), three common pond turtles of the East, the last two being familiar to every fisherman, Clemmys muhlenbergi, a less common species distinguished by its dull brown shell and a yellow blotch on each side of the neck, and found along meadow streams, and the map-turtle (Graptemys geographicus), chiefly of the Mississippi Valley, and distinguished by the yellow streaks and irregular lines which everywhere mark the shell and skin, all belong to the Entyidre, which also includes the familiar land tortoise (q.v.), or box tortoise (Terrapene
carolina) and numerous other species.
Of the true land tortoises (q.v.) (Testudini dee), the gopher turtle (Gopherus Polyphemus) of the Southern States, the European land tor toise (Testudo grceca) and the gigantic Gallapa gos tortoises (Testudo) may be mentioned. See LAND TOWIDISE.
Besides the articles in this work on par ticular kinds of turtles consult Holbrook, 'North American Herpetology (Philadelphia 1842) ; Agassiz, L., (Contributions to the Natu ral History of the United States,' Vols. I and II (Boston 1857) • Boulenger, E. G.,
Chelonians British Museum' (London 1889) ; id., (Reptiles and Batrachians' (New York 1914) ; Hoffman, in Brown's (Thierreichs) (Leipzig 1890) ; Taylor, (Box Tortoises of North America' (Proceedings United States National Museum, Washington 1895) ; Gadow.
Natural History,' Vol. VIII (Lon don 1901) ; True, (The Useful Aquatic Reptiles and Batrachians of the United States' (Wash ington 1834); Williston, S. W.,
Reptiles of the Past and Present' (Chicago 1914). On fossil species consult Hay, O. P.,