516 (van. 18, 
Jope.] 
forwards, on account of the prominence: of the zygomatic arch. There 
are two postparietal foramina, one below and behind, the other on the 
parieto-squamosal suture. The mastoid foramen is not small. The incisive 
foramina are large, are longer than wide, and are separated by a rather 
wide isthmus. The palatine foramina are opposite the third premolars. 
There is a foramen immediately below the postfrontal process. The optic 
foramen issues posterior to the line of the posterior border of the orbit, 
and in front of the anteroinferior angle of the alisphenoid. The 
foramen rotundum is large and round, and is immediately below and 
within the ridge above mentioned, and is not overhung by a transverse 
ridge of the same, as in the species of Merycochwrus known to me. 
The f. rotundum doubtless includes the f. sphenodrbitale. The f. 
ovale is smaller and is separated by a considerable interval from the f. 
lacerum. ‘The latter is subtriangular in form and is rather small, since 
the base of the otic bulla is in close sutural contact with the sphenoid 
and basioccipital for a considerable distance. The f. jugulare is sub. 
triangular in outline and is smaller than the f. rotundum, It is entirely 
distinct from the f. condyloideum, which is the size of the f. ovale. No 
f. supraglenoideum. In comparing these foramina with those of the 
Hi, jacksoni, a general resemblance is to be seen, The frontal fora- 
mina in that species are generally closer together than in ZH, trigonocepha- 
lus, and the palatine foramen is generally opposite the fourth premolar in- 
stead of the third. The foramen magnum is slightly notched on its 
superior border in both. 
The posterior outline of the nasal bones is truncate ; it is more or less 
acuminate in all the specimens of H. jacksoni and H. major accessible to 
me. The prolongation of the frontal on either side of the nagals is also 
short and truncate in this species, and narrow and acuminate in the /. 
jackson and H. major. The lachrymal is deeper than long ; in the species 
last named it is of variable size and form, but is usually as long as deep. 
There is no distinct ridge along the parieto-squamosal suture. The ali- 
sphenoid has a considerable contact with the pariétal. The palatomaxil- 
lary suture is irregularly convex backwards on each side of the median 
line. It erosses the palate as in the H. jacksoni, at the front of the second 
maxillary tooth. 
The teeth are much worn, and the first and last true molars with several 
of the premolars have been lost, indicating the age of the animal. The 
incisors are small and have round roots, The canines are large and of 
the usual form. The space between them and the first premolar is short. 
The fourth premolar is small. The second true molar is wider than long, 
and has no internal cingulum except between the lobes, and has a trace of 
anterior cingulum. 
Measurements. M. 
Axial length from occipital condyles to premaxillary 
POLAEL sis siewieie os vei oles Tee HUE AM calle Vue wareyue t 
Axial length from occipital condytes to postglenoid pro- 
COBB eeaie ling es ceungenete ine ¥ O31 
