920 POEBROTHERIUM. 
= 
When the specimen was received, the right side of the lower jaw contained a 
fragment of a fang, separated from the remaining molars by a hiatus, and situated 
just in advance of the position of the first permanent premolar above, with which 
it most probably corresponded. 
The form of the head, if restored, would probably most approach that of the 
existing Musks, or the extinct Dorcatheriwm, Kaup, from the Middle Tertiary Form- 
ations of Europe. The face is relatively longer than in either of these genera, 
and is also more advanced in position; for in Poebrotheriwm the anterior margin 
of the orbit is on a line with the middle of the penultimate true molar, whereas in 
Dorcatherium it is in advance of this, and in the Musks it is anterior to the first. 
At the side of the nose, the face is depressed into a remarkably deep concavity, 
at the bottom of which the ossa maxillaria of the two sides are nearly in contact ; 
and the face, in this position, is only about two lines and a half in diameter. (Figs. 
1, 2.) The depression may, to some extent, be the result of accident after the 
death of the animal, for the specimen is fractured; the parts, however, generally 
appear to have retained their natural position. 
Dorcatherium also presents a concavity holding nearly the same relative position ; 
but, in consequence of the distance between the orbit and the bottom of the canine 
alveolus being comparatively short in this genus, the depression is close to the 
orbit; whereas, in Poebrotherium it is far advanced by reason of the prolongation 
of the face, which converges from the margin of the orbit to the bottom of the 
concavity. 
Anteriorly, in the specimen, the concavity is abruptly intruded upon by a bulging 
of the face, apparently produced by a canine alveolus like that of the Moschus 
moschiferus and the Dorcatherium. 
Below the concavity of the side of the nose, the face becomes rather abruptly, 
vertically convex; and here, above the anterior fangs of the last temporary molar, 
less advanced than in the Musks, is situated the exit of the infra-orbital canal. 
The anterior and inferior margins of the orbit remain, and show it to have been 
large and subcircular, as in Dorcatheriwm, and to have had a direction outward and 
slightly upward, but apparently not at all forward. The margin of the orbit, 
anteriorly and inferiorly, is everted, and is most prominent at the lachrymal border. 
The malar bone below the orbit is about three lines deep, and, except its slightly 
everted orbital margin, is vertical in its position, so that its lower border is situated 
considerably exterior to the alveolar processes. That border is nearly on a level 
with the edge of these processes, and the maxillo-malar suture curves upward and 
forward from near their edge, about the position of the middle of the last molar 
tooth. Anteriorly to the orbit, the malar bone rises for nearly half an inch above 
its inferior margin, and is there from four and a half to five and a half lines wide. 
The lachrymal bone externally is six lines broad, and forms part of the slope of 
the face converging to the bottom of the concavity at the side of the nose, but pre- 
sents itself no disposition to the formation of a lachrymal sinus. Its orbital face, 
near the margin, is pierced by an infundibular orifice about one line wide to the 
ductus ad nasum. , 
