40 



Tapir, Artiodactyla. 



More than thirty distinct equine species have been found 

 fossil in North America, ranging from. Eohippus (?) in the lowest 

 Eocene, to Equus in the Quaternary deposits. The genus 

 Protohippus of the lower Pliocene equalled the Ass in size. It 

 had three toes on each foot, hut only the middle one, corre- 

 sponding to the single toe of the horse, reached the ground. 

 This genus resembles most nearly the Hipparion of Europe ; 

 whilst the Pliohippus had lost the small hooflets, and was in 

 other respects the most equine. Only in the Upper Pliocene 

 does the true Planus appear and completes the genealogy of the 

 Horse, which, in Post Tertiary times roamed over the whole of 

 North and South America, and soon after became extinct. This 

 occurred long before the discovery of the Continent by Europeans. 



Family Tapirim. — Only a single genus of the family 

 Tapiridce is found living at the present day, the species being- 

 confined to Central and South America and the Malay peninsula; 

 but the fossil forms were distributed over a far wider geographi- 

 cal area. Remains of no fewer than five species may be seen 

 in Pier-case, No. 9. The most important and interesting' are 

 the entire jaws, with teeth, of T. prisons, from Eppelsheim,* 

 T. arvernensis, and T. elegans from France • and T. sinensis, the 

 type specimens, t from China ; and teeth, of a species not 

 identified, from the Red Crag of Sivffolk. 



Lophiodon is an extinct genus nearly approaching the tapirs 

 in its tooth structure, the lower true molars having simple 

 transverse ridges. A.s in the tapir also, there were four toes on 

 the fore-feet and three ou the hind. 



Many species are enumerated, ranging in size from the pig to 

 the rhinoceros. Their remains have been met with in several 

 localities on the European continent, and also in this country, 

 in Eocene Tertiary deposits. 



In Lophiodon the first premolar is absent, and its dentition 

 consists as follows : 



Incisors -f, canines \, premolars ■§-, molars |-X 2=40. 



Axtiodac- 



tyla, 



Bunodonta. 



Sub-order 10. — Artiodactyla (Even-toed Ungulates). 



This well-defined sub-order is traceable from early Eocene 

 times. It is characterised by having the third and fourth 

 digits in both fore and hind feet almost equally developed, 

 and their hoof-bones flattened on their inner or contiguous 

 surfaces, so that each is not symmetrical in itself, but when 



* These specimens are described and figured by H. von Meyer in the 

 " Palaeontographica," vol. xv., p. 173, pis. 25 and 27. 



t Described and figured by Sir Kichard Owen in the " Quart. Joum. Geol. 

 Soc," toL xxvi., pp. 426 to 428, pis. 28, 29. 



