74 THE NEOG^EIC REALM. [CHAP. 



of its history true pigs (Sus), hippopotami (Hippopotamus], camels 

 (Came/us), chevrotains (Tragulida\ giraffes (Giraffida), true deer 

 (Cervus), antelopes, sheep, goats, and oxen, together with a 

 number of extinct forms connecting the ruminants with the pigs, 

 have been conspicuous for their absence. The same is true, 

 among the perissodactyles, of the rhinoceroses (Rhinocerotidce) 

 and the extinct palseotheres (Pal&otheriida) and lophiodons 

 (Lophiodontida) of Europe, and the uintatheres {Uintatheriida) 

 and titanotheres ( Titanotheriidce] of the United States ; while the 

 true elephants (Elephas] among the Proboscidea have likewise 

 been always absent. 



Of the existing South American ungulates the peccaries 

 belong to a family (DicotylidcB) which is abundantly represented in 

 the Tertiary formations of the United States ; while in those of 

 Europe and Asia there occur allied forms apparently connecting 

 the peccaries with the true pigs. On the other hand, in South 

 America their remains occur only in the superficial and cavern- 

 deposits, so that there can be no doubt as to their late intrusion 

 into the country from the north. The vicunas and guanacos are 

 the western representatives of a family (Cameltda) whose other 

 members are Asiatic and African, and of which the past history 

 seems to have been very similar to that of the last group. Fossil 

 camels occur in the Pliocene of India, while a host of extinct 

 genera more or less closely allied to the living South American 

 forms occur in the Tertiaries of the United States ; and since in 

 Argentina and Brazil remains of Lama and the related types 

 occur only in the Monte Hermoso, Pampean, and cavern de- 

 posits, there can be no hesitation in regarding the group as com- 

 paratively recently immigrant into the country. The deer of the 

 genus Cariacus are likewise only known in South America from 

 the Pampean and some other of the later Tertiaries, as well as the 

 Brazilian caves, while in the Pliocene of the United States they 

 appear to be represented by the ancestral Blastomeryx; and these 

 accordingly come under the category of intruders from the north. 

 As regards the tapirs, the genus and family now presents a 

 remarkable instance of discontinuous distribution, one species 

 being confined to the Malayan countries, while all the others are 

 South American. Whereas in the realm under consideration re- 



