1888. ] 71 [Cope. 
wanting, and a number of tooth-bearing fragments. I found a ramus 
with symphysis and part of the other ramus of an individual in Prof. 
Condon’s collection, which I refer for the present to this species. The 
identification rests on the characters of the last two inferior molars, the 
only parts in the possession of Leidy when he described the species. 
The skull is in its proportions intermediate between the extremes in the 
genus. The profile of the long muzzle is a nearly straight gradually de- 
scending line. Viewed from above the muzzle contracts gradually to the 
compression behind the canine alveoli, and then expands to contract 
abruptly in front of the latter, to terminate in the parabolic outline of the 
premaxillary region. The sagittal crest is mostly lost, but it is pretty cer- 
tain that it descends from the profile line to the inion, which is below the 
frontal level. The ridge of the muzzle does not expand above the canines. 
The zygomata are flat. The interorbital region has an undulating surface, 
owing to the presence of swellings on each side of the middle line, and of 
a depression at the supraorbital foramina, and an obtuse median keel be- 
hind them. The postorbital processes are robust and decurved abruptly, 
the apices connected with the skull by a transverse plate with horizontal 
inferior edge. The superciliary border is carried a little anterior to the 
anterior border of the orbit. This border is only distinct above the lachry- 
mal foramen ; below that point the passage from the facial to the orbital 
surface is uninterrupted. The anterior origin of the zygomatic arch is 
equally gradual; posteriorly it arises from the posterior edge of the max- 
illary bone, which forms a line posterior to the third superior molar by 
5mm. Before reaching the longitudinal line of the malar, the border 
turns backwards and terminates in an apex which is directed backwards 
and inwards close to the pyramidal process: of the palatine bone, from 
which it is separated by a fissure. The postorbital process of the malar 
bone is small, compressed and acute. It is anterior to the line of the post- 
orbital process of the frontal. The superior edge of the zygoma is acute ; 
the inferior beveled and truncate. The lachrymal bone extends down- 
wards within the anterior part of the orbit and forms a prominent con- 
vexity whose long axis runs downwards and inwards, and it projects 
behind the posterior boundary of the maxillary bone. It encloses with 
the superior wall of the latter a deep fossa below and continuous with the 
orbit. The orbit is bounded posteriorly by a curved ridge which rises 
behind the foramen rotundum to near the base of the postfrontal process 
and turns forwards and disappears. A much more prominent angle 
commences behind the foramen rotundum and rising vertically soon 
disappears. The temporal ridges are pronounced, and are concave for- 
wards. The lateral occipital crests are prominent and descend to near the 
condyles. The posterior temporal ridge is weak and continued subhori- 
zontally from the zygoma behind, but it does not reach the lateral occi- 
pital crests. The paroccipital process has a robust base which stands at 
an angle of 45°, being less nearly vertical than in the B. subequans. It 
approaches nearer to the posttympanic plate than in that species, being 
