34 Depart?nent of Vei-tebrate Palaontology. 



21. Oreodon culbertsoni Leidy. 



Oligocene Epoch, Big Badlands, S. Dakota. 



Oreodon was first described by Josepli Leidy in 185 1, and is 

 the most abundant and characteristic fossil of the Big Bad- 

 lands. This species is of the size of a peccary, and the skeleton, 

 a composite of two very perfectly preserved individuals ob- 

 tained by the American Museum Expedition of 1894, shows 

 somewhat similar proportions, but is much more primitive in 

 characters, and in most respects has departed comparatively 

 little from the old ancestral type of the Artiodactyla. 



22. Hyaenodon horridus Leidy. 



Am.Mus. No. 1375. 



Oligocene Epoch, Big Badlands, South Dakota. 



This finely preserved skeleton was found by the American 

 Museum Expedition of 1894, and is all one individual, the 

 few missing parts being restored in tinted plaster, HycBUodon 

 is the best-known and the most highly developed of the 

 Creodonta, and is found both in Europe and America. This 

 species is about the size of the Tasmanian Wolf (Thylacinus) , 

 which it resembles to a striking degree in proportions of 

 limbs and feet and in many characters of the skull. 



23. Pantolambda bathmodon Cope. 



Basal Eocene, San Juan Basin, New Mexico. 



Pantolambda is the most ancient mammal of which the 

 entire skeleton is known. This mount is a composite of 

 several incomplete skeletons obtained by the American 

 Museum Expedition of 1896 in the Torrejon (Upper Puerco) 

 horizon of Northwestern New Mexico. It exhibits the 

 short, crooked legs, five-toed, plantigrade feet, long, heavy 

 tail, arched back, primitive skull, with heavy jaws and small 

 brain case, and many other characters which were the coinmon 

 heritage of the early mammals from their reptilian ancestors. 



OsBORN, Evolution of the Amblypoda, Biill. Am. Mus. Nat. Hist., X, 

 1S98, pp. 183-188. 



