1884, | 529 (Cope. 
The mandible possesses some distinctive characters. The angular 
border is not prominent posteriorly, extends forwards below, and projects 
below the general level of. the inferior, border, of the ramus. Neither of 
these characters. is observable in the only ramus of the J. superbus in 
which the lower, part of this border is well preserved, but in some others 
of that species the superior part of the border iis much as in M. maero- 
stegus. The inferior edge of the ramus is ‘straight, but. there is a descend- 
ing tuberosity of the symphysis which may ‘bean individual peculiarity. 
The symphysis is very concave in profile, and the incisive’ border is pro- 
duced in accordance with the prolonged muzzle. In the M. superbus it is 
sometimes convex, sometimes a little concave, but not so much so as in 
this jaw. The coronoid processes. are small and slightly everted. The 
inner ridge of its anterior base is more prominent than the exterior, and 
encloses a fossa, with it... The masseteric fossa) is not’noticeable. There 
is one large, mental foramen below the third premolar. The dental fora- 
men is large and oyal, and when the mandible stands on a level surface is 
opposite the middle, lobe of the third: inferior molar. tooth. 
In dentition this species is distinguished by the relatively large size of 
the premolar teeth, of which the first, second and third are two-rooted in 
both jaws. .Both.the first and second in the upper jaw have short diaste- 
mata anterior and posterior to them, the largest being behind the canine 
tooth, and nearly.as long as the premolar’s crown. All the teeth are a 
good deal worn in the specimen, One can see two internal cingula in- 
closing fossee on the third premolar. The true molars increase in size 
rapidly ‘posteriorly and the third has a well-developed external heel. The 
molars have no internal cingula ; these are present in five of seven skulls 
of the! M. superbus where. these parts .are cleaned. The most noteworthy 
point in the mandibular dentition is a very rudimental character of the in- 
ternal vertical ridge. of the crown of the’ firstipremolar. The posterior 
fossa of the fourth. premolar is closed,.and the anterior remains open, on 
wearing. In &. superbus both are closed in the specimen whete visible. 
The anterior inner. wall is represented in thé second and third premolars 
by a cingulum. No.cingula on ‘the true molars. First premolar very ro- 
bust, its section lenticular. } 
Measurements. M. 
Axial length from occipital condyles* to premaxillary 
BORCRE oi aig 60 yi NE CEN ORR RIOYE OEN NU SG id B85 
Axial length from occipital condyles to postglenoid pro- 
COSR Seve ch sae SOD WEST Gg OU MUI ORIG Nya bebe use ss OAD 
Axial length from opi condyles to postfrontal pro- 
OB aie ined hails iaisein CIV MERE EY SMART Bl i a a MN aes Cea eee 
Axial length from occipital condyles to palatonareal 
DOLE sways ities Lisleta lui PURE Vatdoa a Laat otS ons Cle lonce, . L100 
*The occipital condyles are broken off in the specimen, so I measure from the 
Superior border of the foramen magnum, which is, in the other species, in the 
vertical line of the occipital condyles. 
