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 



