56 



SCIENCE. 



[N. S. Vol. XXIV. No. 602. 



of the Tertiary Vertebrata of the Tayum, 

 Egypt, based on the collection of the Egyptian 

 government in the Geological Museum, Cairo, 

 and on the collection in the British Museum 

 (Natural History), London,' by Charles Will- 

 iam Andrews. The volume is a fine quarto 

 of 324 pages, with twenty-six plates, and a 

 large number of text figures, including several 

 restorations. It is no exaggeration to say 

 that it marks a turning point in the history 

 of the mammalia of the world. 



First and foremost is the fact that the an- 

 cestors of three great orders of mammals, 

 namely, the Hyracoidea, Sirenia and Pro- 

 boscidea, are definitely carried back to the 

 Upper Eocene, and the birthplace of these 

 orders appears to be firmly established on the 

 great continent of Africa, which was espe- 

 cially distinguished through a very long geo- 

 logical period as a land mass much less af- 

 fected by submergence than the other conti- 

 nents, and, therefore, a peculiarly favorable 

 theater for the evolution of terrestrial mam- 

 mals. 



Second, the problematical order of Zeuglo- 

 dontia, aberrant whale-like forms, are defi- 

 nitely carried back to the Middle Eocene and 

 apparently connected firmly with the land- 

 living primitive Carnivores known as Creo- 

 donts. This demonstration we owe to a dis- 

 covery by Professor Eberhard Eraas, of Stutt- 

 gart, a fact which is fully set forth in the 

 present work. 



Third, we have established here the occur- 

 rence of two entirely distinct and extremely 

 aberrant forms of mammals, both of which 

 possibly represent new and distinct orders, 

 namely, Arsinoitherium and Barytherium. 

 Arsinoitherium is now fully known and differs 

 from every other mammal both in its denti- 

 tion and in the anatomy of the skull, a most 

 remarkable feature of which is a very large 

 and forwardly pointed pair of horns. The 

 limbs are analogous to those of the Proboscidea 

 and Dinocerata. 



Fourth, mingled with these aberrant and 

 peculiarly African forms in the Upper Eocene 

 are the only carnivorous types thus far found, 

 namely, the primitive Creodonta, resembling 



those of France and North America, and sug- 

 gesting a land connection and mammalian in- 

 vasion from Europe. Certain of the Artio- 

 dactyl Ungulates characteristic of the Upper 

 Eocene of Europe also appear here, namely, 

 the Anthracotheres. 



We may, therefore, consider the hypothesis 

 which was advanced more or less fully and 

 independently in 1900 by Osborn, Stehlin and 

 Tullberg, that Africa was a very important 

 center in the evolution of mammalian life 

 firmly established as a fact; further, that 

 Africa contributed the Hyracoidea, the Sirenia 

 and the Proboscidea to the continents of 

 Europe, Asia and in part to North America. 



Some confirmation is also found for the 

 hypothesis which dates back to De Blainville, 

 namely, that widely separated as the Sirenia 

 and Proboscidea are to-day, they may have 

 had a community of origin in Lower Eocene 

 times. 



Dr. Andrews is also inclined to regard the 

 evidence which he has now brought together 

 as lending additional support to the theory 

 that in late Mesozoic times Africa and South 

 America were still connected by land. He 

 concludes : ' It appears certain that the final 

 separation of the two continents did not take 

 place till Eocene times,' and that there may 

 have been a chain of islands between the 

 northern part of Africa and Brazil which 

 persisted even till the Miocene. This rests on 

 much more slender evidence than the well- 

 established land connection between Patagonia 

 and Australia, but the resume which the au- 

 thor gives of the anomalies of distribution 

 which would be explained by such a connec- 

 tion is well worth quoting in full (pp. xxvi- 

 xxvii) : 



On the assumption that this series of events 

 did happen, there is little difficulty in accounting 

 for most of the peculiarities in the distribution 

 of the various groups. Thus, to mention only a 

 few instances, the presence in both continents of 

 the Hystricomorphine rodents, of chelonians of 

 the family Pelomedusidse, and of the fishes of the 

 family Cichlidse is at once accounted for. So also 

 is the presence in the Santa Cruz beds of 

 Necrolestes, apparently a close ally of the Cape 

 Golden moles, and of the Sparassodonta, which, 



