1 4 Department of Vertebrate Palceotitology. 



Stage e. — Mesohippus bairdi. Skull and jaws. No. 1477. From 

 Lower Oligocene (Oreodon Beds, White River), Nebraska. 

 Short-crowned teeth of more horse-like pattern. Size of 

 prairie wolf. Price, $8. 



Stage /z". — Hypohippus equinus. Skiill and jaws. No. 8407. From 

 Middle Miocene (Loup Fork) of Colorado. Teeth much 

 like those of Mesohippus. Size of Shetland pony. 



Price, $15. 



Stage i"'. — Merychippus sejiinctus. Skull and jaws. No. 8291. Cope 

 Collection. Middle Miocene (Loup Fork) of Colorado. 

 Long-crowned teeth with cement. Pattern intermediate 

 between Mesohippus and Equus. Size of 3-months-old 

 colt. Price, $15. 



31. Pantolambda bathmodon Cope. 

 Fore and Hind Feet. 



From mounted skeleton in American Museum. No. 2S49. 

 Torrejon Formation (Basal Eocene) of New Mexico. 



Primitive ungulate foot, with five toes, first digit semi- 

 opposable, plantigrade step, wide, loosely joined wrist and 

 ankle-bones (giving much flexibility in all directions at the 

 expense of power) , and other characters now preserved chiefly 

 among arboreal mammals. The foot approaches nearly those 

 of the more ancient unguiculates or clawed animals. Panto- 

 lambda was ancestral to the ancient Amblypoda {Coryphodon 

 and Uintatherium) , but only a collateral ancestor of the more 



recent hoofed animals. 



Price, $j. 



OsBORN, Evolution of the Amblj^poda, Bull. Am. Mus. Nat. Hist.,X, 

 1898, pp. 183—188, figs. 9, 10, 12. 



32. Series of Fossil Camel Feet. 



Illustrating the Evolution of the Camels and Llamas. 



Although now found only in the desert regions of Asia, 

 Africa, and South America, the Camel family was of North 

 American origin, spreading to other continents only in the 

 Pliocene epoch, and becoming extinct in its original home 



