Proboscidea

Abstract

SINCE the discoveries of the late Dr. C. W. Andrews and Mr. H. J. L. Beadnell in Egypt at the beginning of this century, the origin and evolution of the elephants seem to have become clear. They began at the dawn of the Tertiary period in northern Africa as small amphibious pig-shaped hoofed mammals, with a nearly complete set of teeth but the second pair of incisors above and below growing large to become tusks and predominate over the others. In the course of ages, while the primitive elephants developed into larger and less amphibious animals with longer legs, the neck always remained short, so that the head and jaws had to lengthen to reach the ground. The bone of the lower jaw continually lengthened for this purpose, but that of the upper jaw did not do so, and the extension of the face was thus left entirely without hard parts. Throughout the middle portion of the Tertiary period, the long soft face was supported only by the rigid lower jaw. Then in the elephants of later Tertiary times the lower jaw began to shorten, until eventually it left the soft face hanging downwards as the familiar proboscis.

Proboscidea:

a Monograph of the Discovery, Evolution, Migration and Extinction of the Mastodonts and Elephants of the World. By Prof. Henry Fairfield Osborn. Edited by Mabel Rice Percy. Vol. 1: Moeritherioidea, Deinotherioidea, Mastodontoidea. (Published on the J. Pierpont Morgan Fund by the Trustees of the American Museum of Natural History.) Pp. xl + 802 + 13 plates. (New York: American Museum Press, 1936.) 5 dollars.