340 
ARTIODACTYLA. 
pressed in front. The convolutions of the posterior region are the same in 
number as in the Sheep, but are less undulating in their outlines; but there 
is a marked difference in the anterior convolutions. The median convolu¬ 
tions do not, as in the Sheep, extend to the extremity of the anterior lobe, 
but terminate above the Sylvian fissure, so that there only remain in 
front of them the two large supraorbital convolutions, instead of the four 
common to existing Bovidce and Cervidcb."^ In this respect, it more nearly 
resembles Oreodon, but, in this genus, the internal convolution is continuous 
with the supraorbital.f 
A fragmentary loiver jaw of a second individual yxhibits nearly all of 
the lower molars. They present the proportions of those of the P. occiden- 
talis from Nebraska, and are not compressed, or otherwise like those of the 
P. angustidens. 
Restoration. —As a result of the preceding examination, it is evident 
that the Procameliis occidentalis was an animal of about the size of the Llama, 
but one of more symmetrical proportions. The neck was not quite so dispro¬ 
portionately long, while the limbs were more slender and the head and 
muzzle more elongate. The muscular insertions being generally more prom¬ 
inent, we may conclude that it possessed in life greater muscular power, 
and especially agility. 
PLIAUCHENIA, Cope. 
Proc. Acad. Phila., 1875, p. 258; Ann. Kept. Chief of Engineers, 1875, ii, p. 989. 
This genus is established on the dental characters exhibited by a man¬ 
dibular ramus, in the following foi'mula: I. ? 3; C. 1; Pm. 3; M. 3. The 
absence of a premolar tooth distinguishes this genus from Procamelus, the 
second, or first of the continuous series, being the one omitted. A portion 
of the left maxillary bone of a larger species is thought to belong to the 
same genus, although it presents the number of premolars found, in Pro- 
camelus, viz, four. The first and second are, however, very close together, 
so as to leave about the same relative interval between the first and third 
as is seen in the P. humphresiana, should the second premolar be omitted 
* See Leuret et Gratiolet, Auatomie compar^e du Syst^me Nerveux, 1839-57, 
Atlas, plates vii-x. 
t Leidy, Extinct Fauna Dakota and Nebraska, plate xiv, fig. 11. 
