1885.] DR. ST. G. MIVART ON THE ARCTOIDEA. 359 



convex autero-posteriorly. It is greatly narrowed behind the last 

 molars, and hardly more relatively prolonged there than in Cerco- 

 leptes. The sagittal ridge is rather strong. 



The mandible shows a coronoid process, which is loftier and 

 arches more over backwards than that of any of the preceding 

 genera. The inferior margin of the horizontal ramus is convex. 

 There is no subaugular process. The angle is very small, upturned, 

 and little produced. 



The phalanges are very broad, and the ultimate ones have, like 

 those of the Cats, large bony sheaths to shelter the bases of the 

 claws. Nevertheless the penultimate phalanges are not laterally 

 excavated. 



Molar formula =P. |, M. |. 



The incisors are singularly small. The premolars and molars 

 are very interesting to compare with those of Procyon. They are 

 formed on the same type as are the latter, but present a wonder- 

 ful exaggeration of their characters, and are exceptionally broad and 

 multicuspidate. The second upper premolar is a rather large tooth 

 with minute cusps on either side of the base of its great outer cusp, 

 and it has an internal cingulum. The third upper premolar has 

 three outer cusps which are continuous with an external cingulum. 

 There are two internal cusps, whereof the anterior is much the 

 smaller, and another minute cusp is developed from the internal 

 cingulum. The fourth upper premolar has three outer cusps rather 

 distinct from the external cingulum, two subequal internal cusps, 

 and another good-sized cusp developed from the internal cingulum. 

 The first upper true molar has two external and two internal prin- 

 cipal cusps, a strong internal cingulum, and an external cingulum 

 with two supplementary cusps and two vertical ridges. The supple- 

 mentary cusps are placed one in front of and the other behind the 

 antero-external principal cusp. The two vertical ridges descend and 

 lose themselves upon the outer surface of the postero-external 

 principal cusp. The second upper true molar has four main cusps 

 with three external small ones developed from the external cingulum, 

 and one internal cusp developed from the internal cingulum. The 

 first lower premolar is minute and deciduous. The second is like a 

 diminished fourth inferior premolar of Procyon, with the minute 

 supplementary hinder cusj)S added to it. The third is still more 

 like the fourth lower premolar of Procyon. The fourth is also hke 

 it, only that the first cusp is developed almost to an equality with 

 the second, while the third and fourth cusps of the Procyon tooth are 

 represented by a single cusp, which is also almost as large as the 

 second cusp. There is also a median internal cusp. The first 

 lower true molar is like the corresponding tooth of Procyon, but 

 with the hindmost internal cusp represented by two small cusps, as 

 it sometimes is in Procyon. The second lower true molar is like the 

 first, except that the antero-internal cusp («. e. the most anterior cusp 

 of all) of the latter has disappeared, while an additional, median, large 

 cusp appears at the hindermost part of the tooth. 



24* 



