MEGALOIlYIiAX EOCtENUS. 
9:-5 
internal angle of tlie tooth is a small element, which is larger m pm. 4 than m pm. 3, 
and absent in the other premolars, in which the postero-internal angle of the tooth 
forms a shelf-like surface bordered by the cingulum. 
The canine is much worn, but seems to consist of a single blunt cusp borne on two 
roots. Its posterior border is in contact with the anterior premolar. In front of the 
canine the edentulous alveolar border of the maxilla extended for some distance. 
The width of the ])alatc between the last premolars is G'4 cm., and anteriorly 
it must have been very concave from side to side. 
Shill (PI. VI. tig. 1 ; text-tig. 39). — A premaxilla (C. 10009) of extraordinary form 
(PI. VI. tigs. 1, 1 a), bearing a large tusk-like anterior incisor and the alveoli of two 
other teeth, may be ascribed with considerable confidence to the present species. This 
specimen was originally referred provisionally to the problematical Phiomia *, but 
subsequently it was placed in its present position and a figure showing its probable 
relationship with the maxilla of M. eocoenus was given f. The bone consists mainly of 
a socket for the great rootless incisor-tusk (^. 1) which curves round almost in an arc 
of a circle. The anterior border of the bone immediately above the base of the tooth 
is rounded and continues so for some distance up : it then becomes sharp-edged and 
the inner face is marked by a rough surface for union with another bone — the nasal. 
The actual hinder border is broken away. The outer face is rendered strongly convex 
in its upper portion by the socket of the great tusk-like incisor, but beneath this it 
is concave from above downwards, the bone thinning suddenly towards the alveolar 
border. The inner face beneath the surface for the nasal is marked by two broad 
shallow grooves and its lower edge is roughened for union with the overlapping maxilla. 
The palatine process [pl-p.) is a short stout projection which united in the middle 
line with its fellow of the opposite side ; the sutural surface is deepest behind ; it 
does not extend quite so far forwards as the anterior border of the tooth, but projects 
some distance behind its posterior angle. 
The great first incisor (?'. 1) is a rootless tooth, the socket of which perhaps extended 
even into the maxilla. It is triangular in section, one angle being anterior but 
rather nearer to the outer than the inner side, the outer face being narrower than 
the inner. The anterior faces of the tooth are both enamel-covered, the enamel 
being marked by slight longitudinal striae. Both these faces are convex on the whole, 
but are marked by a slight longitudinal groove in the middle, that on the antero- 
external face being the best marked. The posterior face is without enamel ; its 
wear-surface extends from the sharp tip of the tooth to within a short distance of the 
alveolar border. Immediately behind the socket of this tooth there is a deep 
depression formed by the converging edges of the alveolus which meet and form the 
* Andrews and Beadnell, ‘A Preliminary Note on some new Mammals from the Upper Eocene of Egypt ’ 
(Cairo, 1902). 
t Geol. Mag. [4] vol. x. 1903, p. 340, fig. 2. 
