84 ON THE EXTINCT MAMMALIA OF 



of the crown is obtuse or sometimes sub-acute ; the outer and inner borders are both 

 acute. The apex of the crown, at rest, was received in the angular interval between 

 the lower canine and the lateral incisor. 



The inferior canine is straight, and is directed from the bottom of its alveolus 

 obliquely upward, forward and outward. The flxng, variable in form in different 

 skulls, is quadrate with rounded margins, and more or less compressed from without 

 inwardly. Sometimes the quadrate almost assumes the cylindroid form, at others 

 the compressed cylindroid form. The crown is a broad, transversely compressed 

 j^yramid, with trenchant anterior and posterior borders converging to a slightly 

 rounded but sharp summit. It is about the same length as that of the upper canine, 

 but somewhat broader. Both inner and outer faces are angularly convex, the 

 angular character varying in degree in different specimens, sometimes being very 

 pronounced, at others obsolete. In one unworn specimen the inner surface is divided 

 by an acute ridge, and the portions on each side are concave, though generally the 

 divisions of both inner and outer surfaces exhibit towards the base of the crown a 

 more or less feebly depressed condition. 



The crown of the inferior canine projects externally to the contiguous premolar, 

 and is separated from the lateral incisor by a narrow hiatus. It is usually crowded 

 closely upon its contiguous premolar, and when at rest occupies the angular interval 

 and hiatus between the first superior premolar and canine tooth. 



From trituration the canine teeth became exceedingly blunted, their crowns wear- 

 ing away nearly to the level of the molar teeth. The crown of the upper canine was 

 worn away at the point and from the posterior surface. The crown of the lower 

 canine was worn away obliquely at its fore part. 



Enamel invested the crowns of the canine teeth to their base, on a level with the 

 molars. 



The crown of the inferior canine resembles that of the contiguous premolar 

 enlarged and simplified by the suppression of the internal ridges. The position of 

 the inferior canine in its relation with the one above, and the excess in number of 

 the inferior incisors, indicate the former tooth to be a transformed premolar, or a 

 caniniform premolar. 



The incisor teeth of Oreodon are six in number in the upper jaw, including both 

 sides; and they are eigbt in number, as in all recent ruminants, in the lower jaw. 

 They hold about the same relative position with one another as in the Wolf, and 

 they also bear considerable resemblance to those of the latter animal in form, — the 

 lower or corresponding ones even more than they do those of recent ruminants. 

 They form, together with the canines, nearly unbroken arches ; a slight interval or 

 hiatus existing between the lower lateral incisors and canines. They successively 



