Cope.] 68 [Feb. 17, 
prominent externally. At the superior border of the end of the post- 
tympanic plate the meatus auditorius eaternus issues. The posterior ex- 
tremity of the angle of the zygoma rises above it, presenting a concave 
triangular face posteriorly, the apex upwards. The glenoid surface of the 
zygoma is horizontal in front, but its external half posteriorly rises extern- 
ally. The otic bulla is larger than in any of the species here described, 
but its entire boundaries have not been exposed. Its transverse diameter 
is equal to the space between the apices of the paroccipital and posttym- 
panic ridges. The zygomatic arch is rather short, its external face is flat, 
and its vertical depth is considerable. Its posterior angle is very promi- 
nent and compressed. The occipital condyles are small for the size of the 
skull. 
The mandibular condyle projects very little vertically or posteriorly, 
but has considerable transverse extent. Its posterior face is in fact verti- 
cally truncate and the posterior border of the coronoid process rises 
directly from the anterior border of its superior aspect. The anterior edge 
of the coronoid conceals the posterior extremity of the third inferior 
molar. The inferior edge of the ramus is compressed and straight antero- 
posteriorly, and a little convex downwards. The symphysis rises ob- 
liquely but more steeply than the curvature of the ramus. Its median 
suture is preserved. The posterior base of the zygomatic arch is in trans- 
verse line with the posterior border of the third superior molar tooth. 
In Chenohyus decedens it is anterior to this line, and in Bothrolabis pris- 
tinus and B. rostratus it is much posterior to this line. The masseteric 
fossa is well marked but shallow in the vertical direction, not descending 
below the line of the inferior molars. 
The nasal bones are narrow medially, but expand at a point opposite the 
anterior border of the lachrymal bone to four times that width. At the 
middle line posteriorly they present posteriorly an angle which is about 
right. The coronal suture crosses the angle formed by the converging 
temporal ridges, in a nearly straight short line. The apex of the premax- 
illary does not reach the frontal bone by 835mm. The latter borders the 
maxillary by about 10mm. The lachrymal is about as long as deep, and 
presents an angular process backwards into the orbit. The malar rises to 
opposite the lachrymal foramen, and its anterior border does not project 
beyond that of the lachrymal, and retreats a little posteriorly below. The 
posterior suture of the malar is not very oblique; it is concave and 
reaches the base of the postorbital process. The alisphenoid bone has 
little or no contact with the pariétal. The latter descends more than half 
way to the base of the zygomatic process, and reaches the inion poste- 
riorly. The posterior border of the squamosal is anterior to the lateral 
occipital crest. 
The infraorbital foramen is above the middle of the first superior pre- 
molar, The supraorbital foramina are close together, being separated by 
an interspace which is one-seventh of the interorbital space. The Jachry- 
mal foramen is single, large, and within the orbital border. There are 
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