416 E. S. GOODRICH. 



these teeth are (at ail events at the present time) so mutiiated 

 that it is scarcely possible even to recognise their tritubercular 

 character. The outer cusps have been entirely broken away, and 

 only traces of the two inner cusps and the posterior heel remain. 



An outline figure of this fossil has been given by Phillips 

 (24). Professor Osborn in his first paper (14) separated this 

 specimen from the genus Amphitherium with the name of 

 Amphitylus Oweni, under the impression that the molars 

 were tricuspidate.^ There can now be no doubt that this view 

 is erroneous, and that the teeth are really, as Owen described 

 them, of the Amphitherium pattern. Zittel (32) follows the 

 latter in including it in the species A. Prevostii ; but I have 

 retained it as a separate species, chiefly on account of some 

 considerable differences exhibited between the shape of the jaw 

 of this fossil and that of the specimens described above. The 

 coronoid process is straight above and more pointed at its 

 posterior extremity; the condyle is more slender, the notch 

 between it and the coronoid process being more pronounced ; 

 the angle is rather larger, and produced farther back. The 

 premolars, as exemplified by the third and only entire one in 

 this jaw, differ somewhat from those of A. Prevostii; the 

 cusps are more rounded, the main cusp is situated not near 

 the centre of the tooth, but well forward, and the swelling on 

 the fangs, also rather large in the molars, is strongly developed. 

 The molars are unfortunately too broken to compare in detail 

 with those of the previous species. 



The question of the lower dental formula of this genus 

 has been purposely left until after the description of all the 

 specimens. Owen, who evidently saw the second Oxford Am- 

 phitherium (PI. 26, fig. 2) in a more perfect condition than 

 that in which it now is, gave the formula i. 3, c. 1, pm. 6, m. 6 

 (19), describing eight sockets in front of the anterior broken 

 premolar. There can be little doubt, however, that he over- 

 estimated the number of teeth anterior to the four premolars. 

 In front of these can still be seen the broken roots of what was 



' Osborn has since changed his mind, and now, I believe, includes this spe- 

 cimen in the genus Amphitherium. 



