ORIGIN AND DISTRIBUTION OF MAMMALS 305 



descendants of old North American types are the Primates — Parapithecus, 

 Moeripithecus and PropUojnthecus, probably derived from Anaptomorjjhidae, tlie 

 insectivore Metolbodotes, and probably also Ptolemaia and Aletasinopa. The 

 Subungulata are indeed the only truly African element, and even these may 

 have been derived from Condylarthra or the most primitive placentals, and 

 therefore be practically members of the old Arctogaean fauna. In no case are 

 they more nearly related to the South American Notoungulata. 



The existing and sub-fossil mammal fauna of the island of Madagascar 

 exhibits a curious mingling of primitive and modern types. The latter are 

 represented especially by the dwarf form of Hij^j^opotamus, which has obviously 

 come quite lately from the African continent ; while Cryptoproda is in fact only 

 the descendant of a European Miocene carnivore. On the other hand, both 

 the existing and the extinct lemurs, iu part of gigantic size, can only be 

 derived from the Adapidae of the European Eocene, while the Centetidae can 

 only be considered as related to certain insectivores of the North American 

 Eocene, with which they are geographically connected by the West African 

 genus Potamogale and the Solenodon, v/hich lives in Cuba. 



South American Region. 



For a long time the only fossil mammals known from the southern hemi- 

 sphere were those from the pampas and the caves of Brazil in South America, 

 and the extinct marsupials and monotremes from Australia. Our knowledge 

 has only gradually been increased a little by discoveries in the Tertiary of 

 Patagonia. The extensive collections of Ameghino in this region gave us the 

 first real glimpse of the richness of the mammal fauna here entombed, which 

 certainly exhibits a most unfamiliar character. Instead of the artiodactyl and 

 perissodactyl ungulates and the proboscideans to which we are accustomed, 

 here we meet with ungulates which have rather the outward appearance 

 of rodents, such as the capybara, on account of their short skull, usually deep 

 lower jaw, arched back, short and stout fore-limbs, low position of the head, 

 and the short, generally three-toed, feet, often wdth blunt claws, only rarely 

 with hoofs. Others are more like hares. Instead of bats, insectivores, and 

 carnivores, we find marsupials, which remind us in part of the Australian 

 predaceous marsupials, in part of the Mesozoic Allotheria. The Eden- 

 tata also form an important element, appearing early, and indigenous to 

 South America ; while even the rodents, which appear later, belong to 

 families which at the present day are almost exclusively confined to the 

 same continent. However strange this mammal world may appear at first 

 sight, yet certain resemblances to forms of the northern hemisphere are recog- 

 nisable on closer consideration, for some of the hoofed animals, the Litopterna, 

 which in dentition and limbs certainly look like caricatures of the perisso- 

 dactyls, exhibit a certain relationship to the Phenacodontidae, and even the 

 most peculiar Typotheria, Toxodontia, Entelonychia and Astrapotherioidea begin 

 with forms which, in their molar teeth at any rate, are derivable from the 

 Periptychidae — Haploconus and Anisonchus. Likewise, the Grarigrada are also 

 traceable back to types of the oldest Eocene of North America, the Ganodonfa ; 

 and the oldest representative of the armadillos was also perhaps an inhabitant 

 of North America, the genus Metachiromys ; while the marsupials, already 

 mentioned, probably likewise originated in North America, partly from the 



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