384 SCIENCE PROGRESS 



to Nature, August 26, 1922. There have been other articles on 

 the subject in The Times and elsewhere, and these, though 

 mainly popular in character, have served to elicit the fact 

 that some British anatomists, including Elliot Smith, are in- 

 clined to accept Osborn's conclusions, whilst others, including 

 Smith Woodward, are sceptical. If the tooth be really in any 

 sense humanoid, the conclusions to be drawn are certainly 

 far-reaching ; and the reader may be reminded of the present 

 state of knowledge on these matters. The Anthropoidea 

 (higher Primates) are divisible into two sharply defined groups, 

 the Platyrrhina, living in the Western Hemisphere, and the 

 Catarrhina, living in the Eastern Hemisphere. The Catarrhina 

 include not only all species of men and great apes, but also all 

 the familiar monkeys of Asia and Africa. Now there is not 

 the slightest trace of fossil Platyrrhina in the Eastern Hemi- 

 sphere. And, similarly, there has hitherto been no serious 

 evidence that any Catarrhine lived in the Western Hemisphere 

 before that very recent date when Mongoloid savages — ancestors 

 of the American Indians — first made their way across what 

 was then the Isthmus of Behring. The case has therefore 

 appeared to be one in which negative geological evidence 

 really does have some weight. And referring to this new dis- 

 covery Prof. Osborn says : " This is the very first evidence, 

 after seventy-five years of continuous search in all parts of our 

 great western territory, of a Primate of any kind above the 

 ranks of the numerous lemur-like and tarsier-like lower Primates 

 which have long been known in our Eocene beds." On the 

 other hand, a considerable number of Southern Asiatic mammals 

 passed into western America in early Pliocene times, and the 

 existence of free land communication is certain ; the difficulty 

 has been rather the improbability of a continuous forest-belt, 

 suitable for apes, passing as far north as the Behring isthmus. 

 Osborn believes that the tooth is a second upper molar. It 

 was discovered by a geologist named Harold J. Cook in 1921 

 in the so-called Snake Creek beds of Western Nebraska, and 

 Osborn has made it the type of a new genus and new species, 

 upon which he has bestowed the unwieldly name Hesperopithecus 

 haroldcookii. (It may be remarked in passing that it was 

 surely unnecessary to drag in the discoverer's first name.) 

 Osborn will not give any opinion as to whether H speropithecus 

 " is a member of the Simiidae or of the Hominidse." It is, he 

 says, " a new and independent type of Primate, and we must 

 seek more material before we can determine its relationships." 

 The tooth is described in detail, and excellent illustrations are 

 given, with the object of comparing it with the corresponding 

 tooth in Pithecanthropus , in the chimpanzee, and in the American 

 Indian. Another tooth, said to be a third upper molar of an old 



