282 



NA TURE 



[August 26, 1922 



Since 1910 additional discoveries have been made 

 which tend to indicate the existence also of a continuous 

 forest and savanna belt between eastern Asia and 

 western North America (black area and oblique lines), 

 for we have found animals related to the strepsicerine 

 and hippotragine antelopes, to the plains ungulates 

 remotely related to the kudu, to the sable antelope, 

 and to the eland (Taurotragus). We have also traced 

 the migration of two kinds of forest- and savanna- 

 living mastodons over this entire region, namely : (1) 

 of proboscideans closely related to the M. arvernensis 

 of southern Europe, to the M. sivalensis of India, and 

 to the M. mirificus of western Nebraska, specimens of 

 which have now been found in the very Snake Creek 



l of the Second Superior Molars of the Right Side of the UpP' 

 Upper row : crown views of the superior molars. 

 Middle row : anterior views of the same teeth. 

 Lower row : posterior views of the same teeth. 



(1) Hesperopithecus, the new Nebraska Primate, middle-aged. 



(2) Anthropnpithecus, a young chimpanzee. 



(3) Pithecanthropus, adult Trinil Ape-man. 

 (4} Hesperopithecus (photographed in a different light). 



(5) Homo sapiens numgoloideus, aged North American Indian. 



(6) Third superior molar of Anthropopithecus, a young chimp. 

 All photographed to the same scale and natural size. 



beds in which Hesperopithecus was discovered ; also 

 (2) of the true forest-living proboscideans of the genus 

 Mastodon recently recognised in the Snake Creek beds. 

 A true elephant (E. hayi), which resembles the Elephas 

 planifrons of the Upper Siwaliks of India, has been 

 found in more recent deposits. 



From these relatively new and most significant 

 discoveries we may characterise the Snake Creek region 

 n| western Nebraska, in Middle Pliocene time, as in 

 the belt of the south Asiatic forest, savanna, and plains 

 fauna, which extends two-thirds of the way around the 

 entire globe, from the region of Britain to the central- 

 west region of the United States, and probably right 

 across to the Atlantic coast. The plains element in 

 this fauna is extremely abundant, especially the 

 Hipparion ; somewhat more rare are the true horses 

 (Pliohippus), and still more rare are the remains of the 



NO. 2756, VOL. I IO] 



three kinds of antelopes and of the two kinds of mas- 

 todons above mentioned. Finally, of the utmost 

 rarity are the remains of the Primates, because during 

 the eight seasons of continuous and expert search we 

 have only discovered two teeth, namely, the tooth now 

 regarded as a third superior molar of an old individual 

 of Hesperopithecus found by Dr. W. D. Matthew in 

 1908, and the type tooth of Hesperopithecus haroldcookii 

 found by the geologist Harold J. Cook in 1921. We 

 are this season renewing the search with great vigour 

 and expect to run every shovelful of loose river sand 

 which composes this deposit through a sieve of mesh 

 fine enough to arrest such small objects as these teeth. 

 Even by this most laborious and painstaking method 

 « the probability of finding more 



material is not very great, for the 

 reason that the anthropoid Primates 

 have always been very clever and 

 resourceful animals, climbing into 

 trees in times of flood, avoiding 

 the low sandy levels and water- 

 courses where ungulates are trapped. 

 Before re-examining the new 

 figures (Fig. 2) of the Hesperopi- 

 thecus tooth, may I quote verbally, 

 with some unessential omissions, 

 my own original characterisation 

 of the tooth, for which I alone 

 am responsible. 



This second upper molar tooth is 

 very distant from the gorilla type, 

 from the gibbon type, from the orang 

 type ; among existing anthropoid apes 

 it is nearest to m 2 of the chimpanzee, 

 but the resemblance is still very 

 remote. . . . Thus the proportions 

 of the molar crown of the Hespero- 

 pithecus type are about the same as 

 those in the Homo sapiens mongo- 

 loideus type. There is also a distant 

 human resemblance in the molar 

 pattern of Hesperopithecus ... to 

 the low, basin-shaped, channelled 

 crown in certain examples of Homo 

 sapiens. But the Hesperopithecus 

 molar cannot be said to resemble any 

 known type of human molar very 

 closely. The author agrees with Mr. 

 Cook, with Dr. Hellman, and with 

 Dr. Gregory, that it resembles the 

 human type more closely than it does 

 any known anthropoid ape type ; 

 consequently, it would be misleading to speak of this 

 Hesperopithecus at present as an anthropoid ape ; it is 

 a new and independent type of Primate and -we must 

 seek more material before we can determine its relation- 

 ships. It is certainly not closely related to Pithecanthropus 

 mclns ip the structure of the crown, for Pithecanthropus 

 has a single, contracted crown in which the superior 

 grinding surface has a limited crenulated basin, whereas 

 Hesperopithecus has a widely open crown with broadly 

 channelled or furrowed margins, and a postero-internal 

 crest suggesting the hypocone of a higher Primate 

 form. . . . 



The type description, as published in the American 

 Museum Novitates, April 25, 1922, requires little or 

 no modification as a result of two months of inten- 

 sive research which has been devoted to this tooth, 

 detailed results of which will shortly be published 

 by my colleague, Prof. Gregory. The accompany- 

 ing new illustrations (Fig. 2), prepared especially 



the Primates. 



