LOWER JAW. 19 



length, and three in the transverse direction over the articulating surface. 

 The sharp edge of the semi-lunar notch terminates anteriorly in the coronoid 

 process, which is thin and pointed at its extremity, about three inches long, 

 convex on the outside, concave on the inside. The condyloid and coronoid 

 processes are nearly equally elevated ; but the coronoid is in a slight degree 

 lower than the other, in which it resembles that of the elephant, and differs 

 remarkably from that of the tapir, hippopotamus, fossil elk, and especially 

 from the carnivora. The anterior edge of the quadrangle is thick at the 

 root of the coronoid process, and afterwards divides into two ridges; one 

 running inwards towards the dental edge, the other outwards to the body 

 of the jaw. The inferior edge of the branch of the jaw is first smooth ; then, 

 as it approaches the angle, it becomes rough. The angle itself is rough. 

 It rises with some obliquity to the condyloid process, at its junction with 

 which there is a tubercle, while the neck above is very much flattened at 

 its back part. On the outside, below the superior or semi-lunar edge, is a 

 deep fossa, extending from the root of the coronoid to that of the condyloid 

 process, and serving to give attachment to the temporal muscle. The 

 inferior part of this external face of the branch is roughened by the attach- 

 ments of the masseter muscle. 



The external surface of the body of the inferior maxillary bone has 

 a convex form. It presents two considerable apertures : one large, opposite 

 to, i. e. on the outside, and in the same perpendicular line with the middle 

 ridge of the anterior molar tooth ; the other, near the anterior extremity of 

 this face, is smaller ; the first orifice being an inch in diameter, the second 

 half an inch. 



The internal face of the branch is excavated within the coronoid process internal 



Face. 



for the attachment of the temporal muscle. Behind this fossa is the orifice 



