PALJiOMASTODON. 
139 
The 'premaxillce {pmx.) send up a loii^ tongue of bone along the sides of the nasal 
opening, thus completely shutting out the maxillm from any share in its border. 
Anteriorly tlicy are prolonged forwards, forming a projecting snout, on either side 
of which are the alveoli of the large incisor tusks, which must have projected 
forwards and somewhat downwards. Here the only trace of teeth is a portion of 
the crushed base of one of the tusks (^.), probably of the milk-series ; this tooth seems 
to have been enamel-clad on the outer side only. On the palate the premaxillae 
seem to have appeared to a very small extent only, but the precise division 
between them and the maxillae cannot be made out. The upper surface of the 
conjoined bones is slightly concave from side to side, the first indication of the 
form so characteristic of the later Proboscidea. Posteriorly their median suture 
opens for a short distance in a sort of cleft (Hor the mesethmoid cartilage), on 
either side of which they are perforated by a small foramen. The floor of the nasal 
cavity is much more in the same straight line with the upper surface of the anterior 
part of the premaxillse than in Elephas, and the premaxillary portion of the snout, 
as a whole, is relatively much longer and narrower. The nasal opening [nar.), looked at 
from the front, is quadrate in outline ; its upper posterior angle lies considerably in 
front of the orbit and only a little behind the level of the facial opening of the 
antorbital foramen. In EIep)lias, on the other hand, the great difference is that 
the nasal opening is largely behind the anterior border of the orbit, and the whole 
facial region is much shortened up. 
The maxillce [mx.) are not completely preserved posteriorly. In front the facial 
portion extends up the side of the face to the level of the top of the nasal opening, 
and helps to form the anterior border of the orbit. The base of the zygomatic 
process is perforated by a large antorbital canal, which opens on the face by 
two foramina {a.o.f .) — the upper small, the lower much larger. The process itself is 
stout ; it forms the lower border of the orbit, but posteriorly the postorbital process 
is actually formed by the anterior end of the overlapping jugal (ju.) above described. 
The palate is fairly broad and is slightly arched ; it narrows in front, where the 
maxillse seem to run forwards beneath the premaxillae, as in other Proboscideans. 
A restoration of the whole skull founded upon the two specimens above 
described is given in text-fig. 48 (p. 131). 
Upper Dentition (PL XII. figs. 1, 1a; PL XIV. fig. 2). — In the upper jaw there 
are seven teeth on each side : viz., an incisor {i. 2), three premolars, and three molars. 
The first molar is always mucli smaller than the others. 
The incisor is a large, laterally compressed, downwardly directed tusk, sometimes 
with a slight spiral twist ; the anterior edge is rounded, the posterior sharper. 
There is a broad band of enamel on the outer face. One nearly complete 
specimen measures 25'3 cm. long in a straight line. Behind the tusk there is a 
diastema of at least 9-10 cm. 
