AMPHITHERIUM. 51 



The exposed surface of the coronoid process is slightly 

 convex. The surface of the ascending ramus of the jaw 

 is entire above the angle, whence we may conclude that, if 

 the process from the latter part had been continued directly 

 backwards, it would also have been entire ; but the extre- 

 mity of the angular process is broken off, proving it to have 

 originally inclined inwards, or towards the observer : as, 

 however, the greater part of the angle is entire, it could 

 not have been inflected to the same extent as in the Didel- 

 phys, Dasyurus, or the Phascolotherium next to be describ- 

 ed. A groove is extended from the lower end of the 

 articular condyle forward to the orifice of the canal for the 

 dental artery, where it divides ; the upper branch ter- 

 minates in the dental orifice, the lower and larger division 

 is continued forward near the- lower margin of the jaw, 

 gradually contracting and disappearing half way towards 

 the symphysis : this smooth vascular groove has as little 

 resemblance to an articular fissure as in the former speci- 

 men. There is a broader and shorter groove in the corres- 

 ponding part of the jaw of the Myrmecobius ; and a 

 narrower groove in that of the Wombat. The alveolar 

 wall of the posterior grinders makes a convex projection, 

 characteristic of the inner surface of the ramus of the 

 lower jaw. The posterior grinder in the present jaw is 

 fortunately more complete than in the first example, and 

 shows a small, middle, internal cusp, with part of a large 

 external cusp, both projecting from the crown of the tooth 

 in nearly the same transverse line. The enamel covering 

 the internal cusp, which is vertically fractured, is beautifully 

 distinct from the ivory, and considerably thicker in propor- 

 tion to the size of the tooth than is the enamel or its 

 analogue in the teeth of any species of reptile, recent or 

 fossil. The six molars anterior to the one in place, are 



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