TES LP 
LI 
H. F. OSBORN — MAMMALIAN PALÆONTOLOGY 107 
cludes the « giraffe camel », Alficamelus (Marraew', which presents a 
remarkable analogy in the elongation of its neck and limbs with the gi- 
raffes of Africa; similarly Poëbrotherium splits into three phyla (Fig. 5, 
Marraew). Similarly the Oreodont, and Agrichœærine phyla have 
disappeared without leaving successors. The rival cursorial Hyracodon- 
tidæ and aquatic Amynodontidæ having died out, the true Rhinocero- 
tidæ (Fig. 3) split up into three series, one including the extremely 
long-skulled and long-limbed types, possibly related to the true Acera- 
therium incisivum of Europe, a second including excessively broad- 
skulled types (genera Aphelops and Peraceras Cope), and a third inclu- 
ding the short-footed (brachypodine) types (Teleoceras), almost cer- 
tainly ef European origin. The Tapiridæ are still sparsely known. 
The aberrant Chalicotheriidæ terminate in an Upper Miocene species 
which nearly equals in size the Lower Pliocene Ancylotherium of the 
Pikermi. The most astonishing discovery among the Rodentia is that of 
a member of the Mylagaulidæ with a very large horn core on the front 
portion of the skull (genus Ceratogaulus Matthew ?). 
The principal work still to be done in our Miocene is the following : to 
ascertain more fully the character of the Lower Miocene fauna, which is 
still unknown; to fix the date of the arrival of the earliest Proboscidea 
either early in the Middle or in the Lower Miocene; to trace the ancestry 
of the typical dogs; to ascertain the origin of the Cervidæ, which will 
probably prove to be Asiatice, as well as the origin of the peculiarly 
American Antilocapridæ. 
Tue PLIOCENE FAUNA. 
Equivalent to Messinien (Pikermi), Plaisancien (Casino), Astien (Rou- 
sillon), Sicilien (Val d’Arno sup.). 
Our limited American Pliocene fauna still stands in sad contrast to the 
rich succession of Pliocene mammals of Europe. The Palo Duro mammals 
which Core included in the Pliocene have proved to be Upper Miocene. 
Recent geological and palæontological work (Gipzey *) shows that the only 
true Pliocene formation and locality is that of the Blanco beds of Texas, 
75 feet in thickness, as against the rich successive Pliocene series of Eu- 
rope. Nor are any species of Equus found here, as Cope supposed, and as 
might be expected from the presence of Æquus (E. stenonis) in the Up- 
per Pliocene of Europe. The chief faunal distinctions are the entire dis- 
! Foss. Mamm. of the Tertiary, etc. Mem. A. M. N. H. Vol. I, pt. VI, 1901. 
? À Horned Rodent. Bull. Amer. Mus. Nat. Hist., Vol. xvi, 1902, pp. 291-310. 
$ The Freshwater Tertiary of Northwestern Texas. Bull. Amer. Mus. Nat. Hist., 
Vol. xix, 1903. pp. 617-635. 
