122 THE ARTISTIC ANATOMY OF ANIMALS 



below by forming a pointed process which, separated from the 

 intermaxillary bones, is prolonged in front of the nasal orifice. 



The inferior maxillary bone is, as in man, formed of a 

 body and two branches. But among the many special 

 characteristics of form and size which sharply differ- 

 entiate it from the human bone, one detail must be 

 indicated ; this is the absence of a mental prominence. 

 Hence it results that the anterior border of the body of the 

 lower jaw, instead of being directed obliquely downwards 

 and forwards, is, on the contrary, oblique downwards 

 and backwards, and that in certain animals this border is 

 actually found alm.ost exactly on the prolongation of the 

 inferior border of the body of the bone. 



On the external surface of the body are found the three 

 mental foramina. The superior border is hollowed out by 

 alveoli. 



With regard to the branches {rami), they terminate in two 

 processes : one, the posterior, is the condyle ; the other, 

 situated more forwards, is the coronoid process, which gives 

 insertion to the temporal muscle. These two processes are 

 separated by the sigmoid notch. 



For reasons which we will explain further on (see p. 127, 

 movements of the lower jaw), the condyle presents differ- 

 ences of form. In the carnivora, it is strongly convex from 

 before backwards, expanded transversely, and firmly mor- 

 tised in the glenoid cavity of the temporal bone ; in the 

 ruminants, it is less convex from before backwards, it is 

 more slightly concave in the transverse direction ; in the 

 rodents — we give as an example the hare (Fig. 64) — the 

 condyle is still convex from before backwards, but it is 

 flattened from without inwards. 



In the animals in which the muscles of mastication are 

 very highly developed, and especially in the carnivora, the 

 osseous regions occupied by these muscles are more extensive 

 and more deep than in the human species. The length of 

 the coronoid process, the depth of the temporal fossa, the 

 extent of the zygomatic arch, the appearance of the external 

 surface of each of the rami of the lower jaw, deeply hollowed 

 out for accommodation of the masseter, and to provide ex- 



