30 



a single genus, Coryphodon (Bathmodon), is known, but there 

 were several distinct species. They were the largest mammals 

 of the lower Eocene, some exceeding in size the existing Tapirs. 



In the middle Eocene, West of the Rocky Mountains, a 

 remarkable group of ungulates makes its appearance. These 

 animals nearly equaled the Elephant in size, but had shorter 

 limbs. The skull was armed with two or three pairs of horn- 

 cores, and with enormous canine tusks. The brain was propor- 

 tionally smaller than in any other land mammal. The feet had 

 five toes, and resembled in their general structure those of Co- 

 ryphodon, thus indicating some affinity with that genus. These 

 mammals resemble in some respects the Perissodactyles, and in 

 others the Proboscidians, yet differ so widely from any known 

 Ungulates, recent or fossil, that they must be regarded as form- 

 ing a distinct order, the Dinocerata. Only three genera are 

 known, Dinoceras, Tinoceras and Uinta theriiim, but quite a num- 

 ber of species have been described. During the later part of the 

 middle Eocene, these animals were very abundant for a short 

 time, and then became extinct, leaving apparently no succes- 

 sors, unless possibly we have in the Proboscidians their much 

 modified descendants./ Their genetic connection with the 

 Coryphodonts is much more probable, in view of what we 

 now know of the two groups. 



Besides these peculiar Mammals, which are extinct, and 

 mainly of interest to the Biologist, there were others in the 

 early Tertiary which remind ns of those at present living 

 around us. When a student in Germany some twelve years 

 ago, I heard a world-renowned Professor of Zoology gravely 

 inform his pupils that the Horse was a gift of the Old World 

 to the New, and was entirely unknown in America until 

 introduced by the Spaniards. After the lecture, I asked him 

 whether no earlier remains of horses had been found on 

 this Continent, and was told in reply that the reports to that 

 effect were too unsatisfactory to be presented as facts in science. 

 This remark led me, on my return, to examine the subject 

 myself, and I have since unearthed, with my own hands, not less 



