312 MEMOIRS OF THE CARNEGIE MUSEUM 
very slightly arched, and has a lightly rugose surface. There is practically no dif- 
ference in the width of the palate from i* to back of m?®. 
The tympanic region is strongly supported by the postero-internal portion of the 
squamosal. ‘The tympanic bulla is of large size, filled with cancellous tissue, and is 
closely appressed to the postero-internal angle of the postglenoid process. Anteriorly 
the bulla overhangs the posterior nares in a peculiar manner, entirely hiding 
from view the lateral borders of the orifice. The postglenoid foramen is situated on 
the posterior edge of the postglenoid process, between the latter and the tympanic 
region. ‘The foramen lacerum posticum and the condylar foramen are close together 
and are situated, the former internal to, and the latter immediately back of, the base 
of the paroccipital process. The foramen lacerum posticum is at the posterior 
boundary of the tympanic bulla. 
MANDIBLE. 
The lower jaws of the type are in good preservation, except the posterior part of 
the angle which is broken off and lost. The rami are completely codssified leaving 
no trace of the symphysis. The latter is long and curves evenly with the backward 
sweep of the horizontal ramus. The latter as a whole, is rather long and slender, 
diverging only slightly posteriorly,.and has a short constricted area back of the 
canine alveole. The alveolar border is nearly horizontal back of the diastema. The 
latter has a considerable drop below the line of the border, causing on the 
external face of the ramus a constriction similar to that in Dicotyles tajacu. The 
external face of the alveolar border is reinforced by a rugose ridge extending nearly 
the entire length of the border. This feature is also met with in the peccary. The 
internal face of the horizontal ramus is slightly convex. The external surface is 
divided posteriorly by a prominent rounded ridge, which disappears below p,, being 
replaced by a smooth surface. The inferior border of the ramus forms a sinuous 
line, as the angle has a considerable internal flexure. ‘There are three mental 
foramina almost in a horizontal line, and situated below and in front of pe. 
The ascending ramus is strong, its anterior border, or base of the coronoid proc- 
ess, has a prominent ridge extending well forward on the external face of the ramus 
as stated above. The temporal fossa is deep ; it is of considerable antero-posterior 
dimension, but does not extend below the line of the alveolar border of the jaw. 
The top of the coronoid process is broken off, but the base at the sigmoid notch indi- 
cates a rather broad antero-posterior surface. The mandibular condyle has a small 
antero-posterior diameter, while the transverse diameter is considerable. ‘The 
coronoid process rises close to the anterior base of the condyle, forming a small 
superior sigmoid notch. 
