202 R. 8. Lull— Evolution of the Elephant. 



Mammut americanum phylum. 

 (See Chart 1.) 



Tetrabelodon angustidens did not go unaccompanied, for 

 another type, Tetrabelodon turicensis (—tapiroidcs), found 

 in the Lower Miocene of Algeria, must have travelled into 

 Europe by the same route and about the same time. In T. 

 turicensis the grinders are simple in character as though it 

 had already begun to differ in its feeding habits from its con- 

 temporary, in which the teeth are comparatively complex. 

 Tetrabelodon turicensis spread during the Miocene over France, 

 Germany, Austria-Hungary, Russia and as far as southeastern 

 Siberia. The successor of Tetrabelodon turicensis was Mam- 

 mut borsoni, covering much the same geographical area as its 

 forebear, being found as far as England to the north and 

 Russia, along the northern coast of the Black sea, to the east. 

 Geologically it ranges from Lower to Upper Pliocene. M. 

 borsoni merges into Mammut americanum, the great Ameri- 

 can mastodon which outlived the mammoth in the New World. 

 Some teeth found in southeastern Russia have been referred 

 to the American type by Mme. Pavlow, who was perfectly 

 familiar with M. borsoni. However that may be, the migra- 

 tion of this race was without doubt across Siberia, the Retiring 

 isthmus and into the New World from the northwest. The 

 American mastodon's remains have been found from Alaska to 

 California, east to Prince Edward's Island and from Hudson 

 Bay to Florida on the east coast, while Le Conte reports a speci- 

 men from Tambla, Honduras, about 15° north latitude, the 

 nearest recorded approach to South America. 



Tetrabelodon — Dibelo don phylum. 



Tetrabelodon — Elephas phylum. 



(See Chart 2.) 



Reverting once more to Tetrabelodon angustidens, we find 

 in it the possible ancestor of all of the later proboscidians, with 

 the exception of the very aberrant Dinotheres and the Ameri- 

 can mastodon phylum. Tetrabelodon angustidens was a great 

 migrant covering most of Europe with the exception of Spain 

 and England. Its descendants diverged along several lines of 

 specialization as along varied lines of travel, at least one repre- 

 sentative reaching North America in the Middle Miocene 

 (Deep River beds), possibly before (Virgin Yalley of Oregon 

 (Merriam)). The earliest North American form, Tetrabelodon 

 productus, resembled its European prototype very closely and 



