150 FOSSIL MAMMALS OF THE ORDER DINOCERATA. 
third trochanter. The distal end of the femur is more flattened 
transversely than in the elephant, and the condyles are more 
nearly of the same size.. The corresponding articular faces of the . 
tibia are consequently about equal, and also contiguous, with no 
` prominent elevation between them. When the limb was at rest, 
the femur and tibia were nearly in the same line, as in the ele- 
phant and man. The astragalus has no distinct superior groove. 
Its anterior portion has articular faces for both the navicular and 
cuboid, thus differing from Proboscidians, and agreeing with Peris- 
sodactyls. The calcaneum is very short. The phalanges are short 
and stout, and resemble somewhat those of the elephant. 
The vertebra of this group are not unlike those of Proboscid- 
ians in their main characters. The cervicals are materially longer 
than in the elephant. There are four sacral vertebra, the last 
quite small, and supporting a short and slender tail. The ribs 
have rudimentary uncinate processes, as in the mastodon. 
Such being the more important characters of these gigantic 
fossil mammals, it remains to state briefly what these characters 
collectively indicate, and likewise to give reasons for placing the 
group in an order distinct from the Proboscidea. 
The vertebrz and limb-bones in the Dinocerata are in many 
respects remarkably like those of Proboscidians, the exceptional 
characters being those of the Perissodactyl type. The skull, on 
the contrary, presents no distinctive proboscidian features. The 
presence of horns in pairs, and the absence of teeth in the premax- 
illaries together with the large canine, point toward the Rumi- 
pants. The nasal horns, the structure of the anterior portion of 
_ the skull, the molar teeth, the zygomatic arch, the elongated tem- 
; poral fossa, the large post-glenoid processes, as well as other less 
rtant cranial characters, show affinities with the Perissodac- 
| The horns on the maxillaries, the deep concavity of the 
own, and the huge lateral crests are quite peculiar to this order. 
ions of the most marked characters that distinguish these ani- 
nite from the Proboscidea are the following :—1st, The absence 
upper tS 2d, The presence of canines. 3d, The pre- 
ce of horns. 4th, The absence of large air cavities in the skull. | 
| The — oo forms the nasio Foue of the zygomatic 
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