336 IVORY AND THE ELEPHANT 



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Proboscideans, approximately to scale, a. Mwritherium, Eocene, Egypt. 

 h. PalcBomastodon, Miocene, Egypt. c. Tetrabelodon lulli. Pliocene, Nebraska. 

 d. Eubelodon morrilli. Pliocene, Nebraska, a and b modified after Osbom. 



lophodon might be compared with the rhinoceros, although 

 its head was larger. This brings us to the Stegomastodon 

 of the Pliocene or Pleistocene age, which shows a still 

 nearer approach to mastodon and mammoth. In a Pliocene 

 specimen from Texas the upper tusks, although not long, 

 have an upward curve as in the mammoth, and have lost 

 the enamel band characteristic of the older proboscideans.* 

 In India the Pleistocene river deposits, as well as the 

 Siwalik formation (Lower Pliocene) preserve fossil elephant 

 remains, mostly of a type nearly allied to the Indian ele- 

 phant of our own day. Some varieties, however, appear to 

 be representative of intermediate stages of development 

 between the Indian and the African elephants; these are 

 Elephas planifrons and Elephas hysudricus. In these latter, 

 indeed, we are said to have the earliest examples of the true 

 elephant that have been anywhere found. These Indian 

 remains cover many other stages in the evolution of the 

 elephant, and exhibit in a very clear manner the develop- 



*Communication by Dr. W. D. Matthew, Curator of the Museum of Natural History, 

 New York. See also O. P. Hay, "Pleistocene Mammals of Iowa," in Ann. Report Iowa 

 Geol. Survey, Vol. xxiii, p. 373, 1915. 



The Last Lower Molars of Proboscideans, showing progressive changes. 

 , Maerithenum. b. Palwomastodon. c. Tetrabelodon. d. Mastodon americanus. 



