120 0. C. Marsh—Mammals of the order Dinocerata. 
front of the zygomatic arch they contract, and form the inner 
inferior surface of the maxillary horn-cores, as well as an ele- 
vation between them. From this point forward to the anterior 
margin of the suture with the premaxillary, they increase 
slightly in width, and then contract to the end of the muzzle. 
ear the anterior extremity of the nasals, there is a pair of 
low tubercles which evidently supported dermal horns (plate 
II, fig. 3). The premaxillaries are without teeth, and quite pe- 
culiar. ‘iey unite posteriorly with the maxillaries just in front 
of the canine, and then divide, sending forward two branches, 
which partially enclose above and below the lateral portion of 
the narial opening. The upper branch is closely united with the 
adjoining nasal, thus materially strengthening the support of the 
nasal horns. The lower portion is slender, and resembles the 
premaxillary of some Ruminants. The extremity is somewhat 
behind that of the nasals. The anterior nares are comparatively 
small, the aperture being more contracted than in the Rhino- 
ceros. The lower jaw was slender, and the tusks small. 
The extremities in the Dinocerata resembled very nearly 
those in the Proboscidea, but were proportionally shorter. The 
fore legs were somewhat stouter that those behind. The 
humerus was short and massive, and in its main features much 
like that of the elephant. One of the most marked differences 
is seen in the great tuberosity, which does not rise above the 
head, and is but little compressed. The condylar ridge, more- 
over, of the distal end is tubercular, and not continued upward 
on the shaft. The lower extremity of the humerus is muc 
like that of the Rhinoceros, and the proportions of the two 
bones are essentially the same. The head of the radius rests on 
the middle of the ulnar articulation, and hence the shaft of this 
bone does not cross that of the ulna so obliquely as in the ele- 
phant. The femur is proportionally about one-third shorter than 
that of the elephant. The head of this bone has no pit for the 
round ligament, and the great trochanter is flattened and recurved. 
Prof. Cope states that this part of the femur is not recurved, 
but several perfect specimens in the Yale Museum are conclu- 
sive on this point. There is no indication of a 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 con- 
sequently 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- 
hant and Man. The astragalus has no distinct superior groove. 
ts anterior portion has articular faces for both the navicular 
and cuboid, thus differing from Proboscidians, and approaching 
Perissodactyls. The calcaneum is very short. The phalanges 
are short and stout, and resemble those of the Elephant. 
