Page:The American Cyclopædia (1879) Volume XI.djvu/280

 268 MASTODON the ulna much the stoutest, and 34 in. long. The fore foot measures nearly 2 ft. across; the wrist has eight bones, in two rows of four each ; metacarpals five, the first or thumb the smallest (4 in. long), the second and fourth 5 in., the third (the largest) 6, and the fifth about 4; phalanges in thumb two, and in the others three each, supposing an un- gual phalanx to be present in all, though want- ing in the skeleton. The thigh bone is massive and about as long as the humerus, 17 in. in cir- cumference at the middle and 30 at the lower portion; the knee pan nearly globular; tibia human-like, 28 in. long, 30 in. in circumfer- ence above and 13 in the middle ; fibula 26 in., ascending less high than the tibia, but de- scending lower to form the external malleo- lus; feet more depressed, and the toes more radiating, otherwise much as in the elephant. This skeleton is 11 ft. high, 17 ft. from end of face to beginning of tail, the latter being Gi- ft. ; circumference around ribs 16 ft. 5 in.; tusks about 11 ft., of which 8$- project beyond the sockets. The teeth consist chiefly of den- tine invested by enamel, though a layer of ce- ment, thinner than in the elephant, invests the fangs and is spread over the crown. The whole number of teeth is 24, of which rarely more than 8 were in use at one time ; they are de- veloped from behind forward in order to relieve the jaws from the excessive weight of the whole at one time; the outer edge of the upper teeth projects beyond that of the lower. Two on each side in each jaw are developed soon after birth, and are shed early. In the lower jaw, the first is small, 1J in. by, and in. nigh, with two transverse bifid ridges slight- ly notched, and two projecting much curved fangs ; the second, immediately behind it, has the same characters, but is larger, If by 1J in., and IV in. high, with a prominent heel; the third is three-ridged and six-pointed, 3 by 2 in., and 1 high; the fourth is 3J by 2, and If in- high, with the inner mastoid eminence notched ; the fifth is 4i by 3 in., with the in- ner points notched ; the sixth is four-ridged, with complex heel and deeper cleft furrows, 8 by 3 in., and 6 high ; the last sometimes has five ridges. The first and second of the upper jaw resemble those of the lower ; the third is three-ridged, 2$ by 2 in. ; the fourth is three- ridged, 3 by 2J in. (and sometimes much wi- der), with the eminences notched ; the fifth is also three-ridged, 4 by 3 in., each with two eminences; the sixth is four-ridged, with a small heel, the points sometimes bifurcated, and the furrows deep, 6 by 3 in., sometimes larger, even to 9 by 5, and with five ridges. There is no evidence of an additional premolar Tooth of Mastodon. under the second lower milk tooth, though there may be such in the upper jaw, as in other species of mastodon, and in the tapir. At an advanced age the sixth tooth remains alone on each side above and below ; in a case mentioned by Dr. Warren there was a seventh or super- numerary tooth on one side of the lower jaw, 7 in. long and 7J- high. Besides the upper tusks, there are in the mastodon, though not in the elephant, inferior mandibular tusks. The food of the mastodon was entirely vegetable, as is proved by the remains of the twigs of conif- erous trees, leaves, and other vegetable matter found between the ribs ; and the animal doubt- less resorted to marshy and boggy places, like other proboscidians, in search of succulent plants, where it was often mired in the very places whence its remains have been extracted during the 19th century. Around the Shawan- gunk skeleton were found tufts of dun-brown hair varying in length from 2 to 7 in. ; so that the mastodon, like the Siberian mammoth, may have been clothed to withstand a climate considerably colder than that in which modern elephants live. The bones of M. giganteus have not been generally found in a mineral- ized state ; in Dr. Warren's specimen they are light-colored, of less specific gravity than re- cent bones, and retain from 27 to 30 per cent, of animal matter (bone cartilage) ; both bones and teeth, however, have been found silicified, and they are generally impregnated with iron, which it is well known has a great preserving power. The geological position of the re- mains of this species has long been and still is a subject of dispute among geologists ; in a few instances they are said to have been found be- low the drift, in the pliocene, and even in the miocene ; but they have generally been obtained from the post-pliocene or alluvial formations at a depth of from 5 to 10 ft., in lacustrine deposits, bogs, and beds of infusorial earth; Pomel and others consider them diluvial; the bones of this mastodon and of the fossil ele- phant have been found in company in Ohio, South Carolina, Texas, the pliocene of Nebras- ka, and various other parts of North America. Some have thought that the mastodons became extinct since the advent of man upon the earth, like the dinornis and the dodo ; according to Lyell, the period of their destruction, though geologically modern, must have been many thousand years ago. The same causes proba- bly acted in their extinction as in the case of the fossil elephant, perhaps partly climatic changes, but more probably some great con- vulsion on the surface of the globe at an epoch anterior to man. About 30 species of masto- don have been described, for details on which see the work of Dr. Warren and those referred to by him. In South America lived the M. Humboldtii (De Blainv.), belonging to the narrow-toothed group, of which the European M. angu&tidens is the type ; this is charac- terized by the shorter rostrated extremity of the lower jaw, the apparent absence of lower