304 ORIGIN AND DISTRIBUTION OF MAMMALS 



Ovibos-\ike forms, whicli are now completely extinct — Prejitoceras and Eucera- 

 therium — also occur here. The latest Pleistocene faunas of North America, for 

 example, that from a fissure in Arkansas, consist only of Equus, a machairo- 

 dont, and a musk-ox, Symbos, in association with species which still exist in 

 North America. 



Tlie changes in the composition of the faunas, and the extinction or emi- 

 gration of warmth-loving forms both in North America and in Europe, were 

 determined specially by the extending glaciation. In North America the 

 Conard fissure in Arkansas, already mentioned, seems to be the only known 

 locality in which a larger number of the immigrant cold-loving species, or species 

 adapted to cold conditions, have appeared ; but in Europe the fauna of the 

 true ice age plays a much more important part than the preglacial and inter- 

 glacial mammal faunas of warmer habit. There are scarcely any caves in 

 England, Belgium, France, Germany, Austria and Hungary where one would 

 fail to find bones and other remains of cave bear, cave hyaena, reindeer, 

 Rhinoceros antiquitatis and mammoth ; while at times the cave lion, glutton, 

 chamois, and wild goat, as well as saiga antelope and musk-ox, are associated 

 with them. The species now enumerated have also often left their remains in 

 the loess, more rarely in river deposits. Further, a not unimportant element 

 of the latest European Pleistocene fauna are certain rodents — Cuniadus, 

 Lemmus, Ochotona, Dipus, Aladaga and Bohak — Avhich at present inhabit either 

 the arctic tundra or the steppes of Russia and Western Asia. After the final 

 retreat of the glaciers they withdrew indeed to their present habitats. Rein- 

 deer and musk-oxen also disappeared from the temperate parts of Europe, 

 while the lion and hyaena were driven out of Europe by man. More difficult 

 to understand, however, is the extinction of the mammoth, rhinoceros, and 

 cave bear, for it can scarcely be assumed that man alone exterminated them as 

 he killed off the giant deer, bison and aurochs. 



African Region. 



Until this century no fossil mammals were known from Africa except those 

 from the Pleistocene of Algeria and a few fragments from the Tertiary of tlie 

 same country. Nevertheless, Africa played an important part in zoogeographical 

 speculations. It must have been especially the home of all the Pliocene 

 mammals of Europe and Asia ; there may also have been a great African- 

 South American continent, and even the new forms now and then appearing 

 in the European Eocene must have come from Africa. Now that we know 

 remains of land mammals, botli from the Eocene and Oligocene, and from the 

 Miocene and Pliocene of Egj^pt, it is clear that these two later faunas comprise 

 no other elements than the contemporaneous mammal faunas of Europe and 

 Asia ; and therefore that Africa, at least Northern Africa, already belonged 

 faunisticall}'^ to Eurasia. In the Eocene the land mammal fauna is confined to 

 two genera, Moeritherium and Barythermm, which are both Subuvgtdata; and 

 the fauna of the Oligocene is distinguished by a peculiar mingling of indi- 

 genous forms, Subungidata—Prohoscidea, Palaeomastodon and Moeritherium — 

 Hi/racoidea — the numerous Saghatheriidae — and Arsinoitheriiim, with immigrants 

 from North America and Europe. From Europe originate Ancodus, Apterodon, 

 Fterodon, and an indeterminable large creodont, the rodents Phiomys and 

 Metaphiomys, and indeed also the bat, Provampyrus. On the other hand. 



