90 PROFESSOR OWEN ON THE OSTEOLOGY OF 
of the sockets of the incisive and canine teeth; the outer walls of these sockets are 
a little prominent, chiefly so in the canines, and also where the anterior root of the 
first premolar is implanted. A thin ridge of bone extends along the outer side of the 
openings of the molar sockets, beneath which there is a shallow longitudinal channel 
which insensibly passes below into the flat surface of the bone, which becomes convex 
towards the lower border. 
A little behind and below the prominent part of the first premolar alveolus, and 
a little nearer the lower than the upper border of the bone, is the ‘ foramen mentale’ : 
I have seen it double on the right side, the smaller division being in advance of the chief 
opening: two or three much smaller foramina open behind this. 
There is a low tuberous rising near the lower border of the bone, below the beginning 
of the fore and outer part of the ascending ramus. ‘This ramus commences from a 
platform of bone which extends outwards beyond the alveolus of the last molar; a 
strong ridge, continued from the back part of that alveolus, inclines, as it rises, towards 
the outer ridge which it joins, after it has bounded the fore part of the crotaphite 
depression. 
The lower border of the horizontal passes into the hinder border of the vertical ramus 
by a pretty regular convex curve, without a projecting angle: the outer part of this curve 
forms a low, rather sharp ridge: the inner part presents four or five tuberosities bound- 
ing intermediate concavities (Plate XXXII. fig. 2). The outer surface of the rising 
ramus is nearly flat: there is a feeble middle rising and a shallow depression anterior 
to this. The anterior border rises nearly vertically and straight for two-thirds of its 
extent, then curves gently backwards to the summit of the coronoid process. This 
summit is pointed and is divided from the condyle by a deep and pretty regular 
concavity, formed by the upper border of the ascending ramus, which terminates near 
the outer side of the condyle. 
The condyle is convex, subovate, with its long axis transverse, and its larger end 
inwards: the fore part of its articular surface terminates by a well-defined line or ridge ; 
the back part curves downwards to a lower level, and is insensibly lost on the neck of 
the condyle: there is a rough protuberance below the outer end of the condyle; and a 
more extensive rough surface below the inner end, which overhangs the rising ramus. 
The smooth, broad, convex rising which bounds the lower part of the crotaphite fossa 
terminates at the fore and inner part of the condyle. 
The inner side of the symphysis presents at its lower fourth part a rough, oval, 
shallow depression traversed by a slight median vertical ridge, which terminates in the 
rough, transverse, broader ridge bounding the depression below. The inner surface 
of the horizontal ramus is smooth ; a sudden but slight sinking marks the beginning 
of the inner surface of the ascending ramus. This surface is divided by the ridge 
leading to the condyle into an upper and lower part: the upper and smaller depression 
receives the insertion of the crotaphite muscle ; the lower one is pierced by the dental 
