18 



vertf:brata. 



The two plans of foot structure are found in the Tertiary with both 

 kinds of dentition, but no species survive witli the "inadaptive" plan. 



The Camels and Llamas diverged from the primitive stock in the 

 Eocene, and became in the Pliocene the most abundant of the 

 larger animals, except the Horse family. The hollow-horned rumi- 

 nants appeared in Europe in the Miocene, but have not been found 

 in America earlier than the Pliocene. 



The true Sheep, Goats, Giraffe, Hippopotamus, and Old World 

 Suillines {Stts, Porous, Phacochoerus), have not been discovered in 

 America. 



FAMILY BOVID^. 



No. 36. [48] Sivatherium giganteum, Falc. and Caut. 



Skull (Male), (cast). This singular ele- 

 phantoid Antelope exceeded the Rhinoceros 

 in size, and had some affinity with the Gi- 

 raffe. The head was very large, broad but 

 short, and carried four horns; the tirst pair 

 resembled those of the Cow, and was placed 

 just between and above the orbits; behind 

 these was the other pair, palmaled and 

 branching, like those of the Elk. The pos- 

 terior part of the cranium was enormously 

 developed and cellular as in the Elephant. 

 The face was short; the eyes small and 

 lateral ; and the nasal bones were prolonged 

 into a' pointed arch, indicating a proboscis. 

 The very inclined direction of the front of 

 the face, in relation to the triturating surface of the teeth, impai-ts a peculiar 

 physiognomy. The animal must have had a compound stomach, though the 

 teeth seem fitted for bruising and crushing the branches and twigs of trees. 

 The enamel is rugosely furrowed, and the inner crescent presents sinuous 

 plaited flexures. The fossil was discovered in the Valley of Markanda, among 

 the Sewalik Hills of India (Pliocene), and is now in the British Museum. 



Size, 21 X 20. 



No. 27. [55] 



Ovibus (Boothermm) bombifrons, Leidy. 



Cranium with hokn- 

 CORES (cast). This ancient 

 Musk-Ox is closely allied 

 to the living species, and 

 wasdoiibtless cotemporarj'^ 

 with the gigantic wild oxen 

 of Europe. The specimen 

 was found in the Pleisto- 

 cene morasses of Big-bone 

 Lick, Kentucky, and is in 

 the Academy of Natural 

 Sciences, Philadelphia. 



Size, 18 X 12. 



