APEIL a9, 1898.] 



SCIENCE. 



587 



Elephants, some were hairy and others 

 naked. The top of the head was doubt- 

 less naked posteriorly, and in old ani- 

 mals may have been only covered by a thin 

 epidermis, as in the Crocodiles, thus pre- 

 senting a rough, impenetrable front to 

 antagonists. 



" The movements of the Coryphodons, 

 doubtless, resembled those of the Elephant 

 in its shuffling and ambling gait, and may 

 have been even more awkward, from the 

 inflexibility of the ankle. But, in com- 

 pensation for the probable lack of speed, 

 these animals were most formidably armed 

 with tusks. These weapons, particularly 

 those of the upper jaw, are more robust 

 than those of the Carnivora, and generally 

 more elongate, and attrition preserved 

 rather than diminished their acuteness. 

 The size of the species varied from that of 

 a Tapir to that of an Ox." 



Osborn* in 1892 wrote as follows : 



" The fact is, the position of the fore and 

 hind feet of Coryplwdon is absolutely dif- 

 ferent. The fore foot ivas digitigrade, like 

 that of the Elephant ; the hind foot was 

 jplantigrade, like that of the Bear. In other 

 words, the carpus was entirely raised from 

 the ground and the manus rested upon the 

 distal ends of the metacarpals and upon 

 the spreading phalanges, while the cal- 

 caneum and tarsus rested directly on the 

 ground, together with the entire pla,ntar 

 surface of the foot. This substantial dif- 

 ference between the advanced state of 

 evolution of the fore foot and retarded 

 evolution of the hind foot is of great inter- 

 est. It is clearly shown in the accompany- 

 ing figures." 



In 1893 Marsh,f in his description and 

 restoration, presented quite a different con- 



*rossil Mammals, of the Wasatch and "Wind River 

 Beds, Collection of 1891 ; Osborn & Wortman, Bull. 

 Am. Mus. Nat. Hist., Sept., 1892, p. 121. 



t ' Restoration of Coryphoclon,Mme?-. Joxir. Science, 

 Oct., 1893, p, 324. 



ception of the animal as ungidigrade. In 

 regard to these matters he made the follow- 

 ing statement : '' The position first given 

 to the figure is retained in the restoration 

 after a careful investigation of the whole 

 posterior limbs in a number of well-pre- 

 served specimens. In Dmoceras the ter- 

 minal phalanges are much larger than in 

 the Elephant, so that they thus bore a 

 greater weight, the digits being undoubtedly 

 free, although a pad may have helped to 

 support the feet. In Coryplwdon the digits 

 were still more elongate and the ter- 

 minal phalanges proportionately larger and 

 broader, indicating that they were covered 

 with hoofs that supported the feet. This 

 would agree with the position given them 

 in the restoration, which coincides with 

 the anatomical structure of the entire hind 

 limb." 



It appears from our more complete ma- 

 terial that the difi^rence between the feet 

 , was exaggerated by Osborn, as already 

 observed by Marsh. There is no doubt, 

 however, that, as seen in the mounted speci- 

 men, in the forward step the calcaneum 

 rested very near the ground, being separated 

 merely by a thick plantar pad. The digits 

 of the fore and hind feet have nearly the 

 same relations to the ground. Both feet are 

 in a somewhat similar stage of transition betioeen 

 plantigradism and digitigradism. Pantolamhda 

 has a long tuber-calcis and pes like that of 

 the Bear. Uintatherium has a very short 

 tuber-calcis and bore the pes slightly more 

 plantigrade than the elephant. Coryphodon 

 has a tuber-calcis intermediate in length ; in 

 the astragalus the upper facet for the tibia 

 and lower facet for the navicular presents 

 an oblique angle, the astragalus thinning 

 out to a sharp edge in front (whereas in 

 Uintatherium these facets are more nearly 

 parallel, and the astragalus is truncate in 

 front). The angles between the tibial and 

 navicular facets of the astragalus, as shown 

 in sections in Fig. 2, afford the most de- 



