234 
PALEONTOLOGY: H. F. OSBORN 
Proc. N. A. S. 
8. Brevirostrinae, short-jawed bunomastodonts, which imitate both the true 
mastodonts and the elephants in the abbreviation 
of the lower jaw and the early loss of the inferior 
tusks. These animals wandered all over Europe, 
Asia, and western North America. 
IV. BLEPHANTOIDEA (the Elephant stock) 
9. Stegodontinge, the original members of which were doubtless ancestral to all the 
higher elephants, persist as an independent branch 
into the Lower Pleistocene of eastern Asia. 
10. Loxodontinse, embracing the great African division of the elephants be- 
ginning with Loxodonta antiqua of the Upper Pliocene, 
which wandered all over southern Eurasia and radiated 
widely over Africa. 
11. Mammontinse, including (a) the Southern Mammoths (Elephas planifrons 
of India and E.. Meridionalis of Europe), from which 
is derived E. imperator of North America, and (b) the 
Northern Mammoths, which probably include E. 
columbi and the widespread E. primigenius of the 
northern steppes; tetradactyl pes. 
12. Elephantinae, the true elephants (E. indicus of India), which do not appear 
until the Upper Pleistocene; pentadactyl pes. 
This twelve-fold branching of the proboscideans is similar to the adap- 
tive radiation which the author has traced in the evolution of the horses, 
of the rhinoceroses, and of the titanotheres, carrying the fundamental 
lines of separation back to the Middle Miocene as the most recent date, 
and to the Middle or Lower Eocene as the most remote date. 
It will be observed from the diagram that the shaded areas 
represent those phyla of which remains have been discovered. The 
large unshaded area includes the entire Oligocene, Miocenes, and Lower 
and Middle Pliocene history of the Elephantidse which is still unknown 
but which is likely to be revealed at any time by discoveries both in Africa 
and in central Asia. A very striking fact is that the geologically earliest 
known member of the Elephantoidea is the Elephas planifrons of the 
Upper Pliocene of India, the apparent ancestor of the mammoths. 
1 The first paper in this series is entitled, "A Long-jawed Mastodon Skeleton from 
South Dakota and Phylogeny of the Proboscidea," Bull. Geol. Soc. Amer., March, 1918; 
the second paper, "Evolution, Phylogeny, and Classification of the Proboscidea," 
Amer. Mus. Novitates, No. 1, January 31, 1921 (Osborn, 1921. 514); the third paper, 
"First Appearance of the True Mastodon in America," Amer. Mus. Novitates, No. 10, 
June 15, 1921; the fourth paper appears in the Bulletin of the Geological Society of 
America, under the title, "Evolution, Phylogeny, and Classification of the Mastodon- 
toidea;" the present is the fifth paper. The Iconographic Type Revision will form one 
of the Memoirs of the American Museum of Natural History. 
« Herluf Winge, 1906, p. 172. 
* Ibid. 
4 It is a question whether this subfamily is nearest the Mastodontidae, with which 
its members are generally placed by European palaeontologists. 
