463 



URSUS. 



Polar Bear ; ' but in the instances observed the corresponding upper 

 molar was constantly present. 



Of the other molar teeth, the alveoli only are shown ; of these an- 

 terior teeth there were four. First, a small premolar separated from the 

 canine by the interval of about a line, as in the Polar Bear ; then a 

 vacant barre, 08 of an inch in extent, followed by another single- 

 fanged premolar ; this tooth Avas succeeded by a two -fanged last pre- 

 molar in close apposition ; and lastly, there is seen the double fang of 

 a first molar, followed by the two-fanged alveolus of m. 2. 



The penultimate molar in a general way presents the characteristic 

 form of crown seen in the Bears; but it differs remarkably from all 

 the specimens with which we have compared it, in the excessive width 

 in proportion to the length of crown. In the Polar Bear, Ursus ferox, 

 and Ursus Arctos, the crown of the penultimate is commonly a narrow 

 oblong, while in the fossil it is of a very broad oblong form, as in 

 U. spelceus ; the coronal surface is slightly worn, but not to the extent 

 of confounding the prominences. On the inner side (as in the Grisly 

 Bear, 1137, B.) there are four points, the two anterior of which occu- 

 pying the front half are obtusely pyramidal, and somewhat as in the 

 Grisly Bear, 1137, B., but less salient. They are slightly abraded at 

 the apex. The two posterior inner points are much smaller, nearly 

 equal in size, and depressed so as to form a step below the anterior 

 points. 2 The outer side consists, as in the Grisly Bear, of two prin- 

 cipal points, the anterior of which is ground down into a three-pronged 

 disc ; the posterior point is lower, and slightly abraded. In all these 

 details of coronal prominences, the tooth of the fossil corresponds very 

 closely with that of the Grisly Bear, although still maintaining a con- 

 siderable difference in the proportion of length to width. 



In the Cashmeer Ursus Isabellinus, 1010, F., the crown of the pen- 

 ultimate is broad in proportion to the length, but the surface is exces- 

 sively warty and complex, resembling more that of a Plog, and some 

 forms of U. spelceus. In Ursus Arctos the tooth is very much smaller, 

 and narrow in proportion to the length, with finely warty subdivisions 

 of the surface. In the Polar Bear, 221, B., the wartiness is still finer 

 and more complex ; this is beautifully shown in the last molar of that 

 species ; on the other hand, in all these details of surface, the crown of 

 the fossil, as regards simplicity of pattern, approaches nearest the Grisly 

 Bear, 1137, B. 



The muscular impressions of the temporal show the fossil to be oldish. 



In form of jaw, lower line of ramus, the fossil comes nearest the Polar 

 Bear, in which the angular jwocess rests on the ground plane ; it does 

 nearly the same in fossil. But in the Polar Bear there is no crook 

 process under the middle of the coronoid. There is more or less crook 

 in all the others. In U. Arctos, the Cashmeer Bear, and U. ferox, the 

 angular process is well raised above the ground plane, and enormously 

 so in U. spelceus. Coronoid in fossil broader and lower than in any of 

 the others : nearest U. ferox ; it has a crescentic outline behind : quite 

 different in U. sjjelwus. Condyle in great depth and shortness, most like 



1 Thus, in the Brit. Mus. specimen of 

 Polar Bear, No. 221 Gr., there is no indi- 

 cation of an inferior last molar on 

 either side, and in 221 B. it is present 



on the left side, but not on the right. 



2 In the Grisly Bear the points are 

 nearly of uniform height from front to 

 back. 



