386 AN INTRODUCTION TO THE STUDY OF FOSSILS 



small rock- and tree-living hoofed animals include the coney 

 (Hyrax) of Africa and southwestern Asia. 



(3) The extinct Amblypoda (Eocene of North America) were 

 huge, heavy-limbed, blunt-footed animals. They include the 

 huge hippopotamus-like Coryphodon, and the giant Dinoceras, 

 Uintatherium (Fig. 163, 6), Eobasileus, etc., with three pairs of 



bony, horn-like prominences upon the top of 

 the skull. 



(4) The Proboscidea, the elephant tribe 

 (Upper Eocene to present), are primitive 

 ungulates. Each of the massive limbs 

 terminates in five toes which are separately 

 incased in hoofs (Fig. 167). Canine teeth 

 are absent ; the molars are large and trans- 

 versely ridged. These molars (Fig. 168) 

 come in successively from behind and move 

 obliquely forward to be finally, when worn 

 down very low, pushed out from the front 

 of the jaw. Owing to the great size of the 

 teeth and the shortness of the jaw, only one 

 tooth on each side, above and below, is in 

 full use at one time. In existing forms 

 there is only one pair of incisors present, 

 the upper ; these are free from enamel and 

 are developed into continuously growing 

 tusks. Many early forms had tusk-like 

 incisors both above and below (e.g. Paleo- 

 mastodon [Fig. 169] of the Upper Eocene of northern Africa). 

 As is true of all animals, there is seen in the elephant a persist- 

 ence of primitive, archaic characters alongside of highly adap- 

 tive, modern ones. The elephant retains the primitive mam- 

 malian form of body, the five toes and the carpal bones arranged 

 in vertical rows, but these are associated with such highly 

 specialized characters as reduction in number of teeth, remark- 

 able growth of two incisors, wonderful increase in height of 



Fig. 167. — Vertical 

 section through the 

 fore foot of the In- 

 dian elephant. U, 

 lower end of ulna ; 

 L, lunar bone of the 

 carpus (wrist) ; M, 

 magnum of carpus ; 

 ///, third metacarpal 

 (palm) bone ; /, 2, 

 3, phalanges of the 

 third digit (middle 

 finger) ; E, pad of 

 elastic tissue. (From 

 Scott, after M. 

 Weber.) 



