URSUS. 13 



definite cusp. The marginal portion of the triangular area is slightly raised. The 

 root, which in each case is rather more than twice as long as the crown, is con- 

 siderably laterally compressed. 



In bears of the arctos type the posterior area is more sharply marked off from 

 the cone than in the cave bear. 



I. 3 is a larger and more caniniform tooth, with a prominent, sharply reflected 

 cone. There is no depressed posterior area as in I. 1 and 2, but a slight cusp is 

 developed on the inner side, and from it a cingulum extends along the inner and 

 posterior margin of the crown. The root is not so much laterally compressed as 

 in I. 1 and 2. 



In bears of the arctos type this tooth differs only in size and in the slight 

 development of the cingulum. 



C. The canine has the form usually met with in Carnivora. Its crown 

 constitutes about one third of its length, and is frequently, though not invariably, 

 marked by a wide, shallow groove along its inner face, and by a slight ridge along 

 its posterior face. The crown is slightly longer and more recurved and pointed 

 than in Hyaena, and the root tapers more than in that animal, and is more massive 

 than in Felis. Size constitutes the only difference between the canine of the cave 

 bear and that of bears of the arctos type. 



Pin. 1 and 2, which are almost invariably absent in the cave bear and irregular 

 in their occurrence in bears of the arctos type, are small and simple teeth, with a 

 low crown and long cylindrical root. 



Pm. 3, which is absent as a rule in the cave bear, is in bears of the arctos 

 type a small tooth with well-developed cone and slight indications of anterior and 

 posterior cusps. The cingulum is slightly developed on the inner side. 



Pm. 4, the upper carnassial, has the blade divided into a prominent anterior 

 cone (a) 1 and a less elevated posterior cone (b), behind which is commonly a slight 

 additional cusp. Lying postero-internally to the blade is a large inner cone or 

 lobe (PI. VI, fig. 1, c), which shows considerable variation. The cingulum is often 

 strongly marked, especially antero-internally. There are two roots, a smaller 

 anterior one supporting the anterior cone of the blade, and a larger posterior one 

 supporting the posterior cone of the blade and the inner lobe. 



In bears of the arctos type the cingulum is not so strongly marked, the inner 

 cone or lobe tending to be relatively larger than in U. spelseus, and often having 

 a slight additional cusp cut off from its posterior edge, sometimes also from its 

 anterior edge. This inner cone or lobe, which is posteriorly placed, must not he 

 confused with the inner tubercle characteristic of the upper carnassial in Felis, 

 Can is, and Hyaena, which is anteriorly placed. 



M. 1 has a large, somewhat quadrangular crown with the surface raised into 



1 This and the following letters refer to Plate VI. 



