THE STRUCTURE AND RELATIONSHIPS OF ANCODUS. 467 
matic process, and is plane transversely; antero-posteriorly it is made concave by 
being continued upon the postglenoid process. The latter is long, stout, and taper- 
ing d^tally to a blunt point, and thus has an entirely different shape from that of 
Oreodon,m winch it is broad, massive, and of uniform height. The zygomatic 
process is very like that of Oreodon-, its root is much extended in the fore-and-aft 
direction, reaching over the auditory meatus and posttympanic process, its raised 
outer border passing into and continuous with the lambdoidal crest. The zygomatic 
process itself is thin and compressed, but has considerable vertical depth ; it arches 
downward and forward, pursuing a less straight course than in the Eonzon species. 
Anteriorly the process tapers to a blunt point which is received into a notch of the 
jugal beneath the orbit. The zygoma is not so long as in Oreodon, which has the 
orbit considerably farther forward, but in other respects the resemblance is close. In 
Oreodon the contact of the zygomatic process with the jugal is shorter and hence the 
former is less attenuated anteriorly. 
The jugal is quite a massive bone; beneath the orbit it is deep vertically, but 
gradually tapers backward, where it passes beneath the zygomatic process. It is 
relatively longer than in Oreodon, and is not separated from the glenoid cavity by 
so wide an interval as in that genus. The postorbital process, though short and 
not nearly reaching that from the frontal, is nevertheless more conspicuously de- 
veloped than in the European species. The jugal does not appear to be much ex- 
panded on the face in front of the orbit. 
As in Oreodon the lachrymal is large and forms much ol the anterior boundary 
of the orbit, but there is no such pit or depression as occurs in that genus. The 
foramen is single and is placed within the edge of the orbit. 
The frontals together make up a short, broad, lozenge-sliaped area. Pos- 
teriorly they send back narrow prolongations, which are received between the 
parietals and form a very limited part of the roof of the cerebral chamber. An- 
teriorly they are deeply notched to receive the nasals, while the nasal processes are 
long and have extensive sutures with the raaxillaries. Owing to the prominence 
of the orbits, the forehead is very wide, much more so than in A. velaunus, and is 
slightly concave transversely, not being inflated a..d roonded bv e.nueee as .a he 
case i„ Oreodm. As in the latter, the anpraorbital Ihremma are placed near l e 
medhan line, but the va.eeular grooves which run forward iiom them arc longer and 
T ,1 • j Tlio nnstorbital process of the frontal is considerably' 
more distinctly impressed. I he postoroiiai piucf . The 
longer than in 1 velaunus, h.i the orbit remains widely open behind. 
temporal ridges encroach but elongation of the muzzle; 
The nasals are very long, somewhat convex from side 
they are broadest narrowing a^i premaxillaries and 
to side. The anterior ends project little, it at an, y 
are notched in the middle. antero-posterior extension, the in- 
The p,e,na,villarie, have » sanrc fore-and-aft line, 
oisors being well spaced apart an aw „ process is long, low. 
The alveolar portion is solid and massive, 
61 JOUEN. A. N. s. PHILA., VOL. IX. 
