90 PROF. E. LONNBERG : EEMARKS ON 



off, even on the inner side of the tooth and not only on the 

 outer. On m^ it is very strongly developed on the inner side, 

 where it forms a distinct shelf (PI. II. fig. 5). On the outer side it 

 is weaker, but quite traceable, p^ has a well-developed antero- 

 interior cingulum cusp. 



The great size of the molars is relative as well as absolute (cf. 

 PI. II. ligs. 5 & 6). The greatest length of m^ that I have ever 

 seen when examining a considerable number of Swedish Bears is 

 35 mm., while the same tooth in the present specimen of the 

 pruinosus group measures 41 mm. The difference in breadth is 

 still more striking, because m^ of Swedish Bears is seldom more 

 than about 17 mm. broad, while in the present pruinosus speci- 

 men it even exceeds 22 mm. The combined length of j»*, «i\ and 

 m^ is in Swedish male Bears, as a rule, not more than about 

 70 mm. and often less, and among the skulls examined by me it 

 was only once 73 mm.; in the jouug pruinosus, however, it is as 

 much as 83 (84) mm. The dimension in question is, in adult 

 males of the former kind, less than the distance between on' and 

 the processus postglenoideits, and a.lso less than the interorbital 

 breadth, but in the pjnoinosics the former dimension is larger than 

 the two others. 



In pruinoszLs the combined length of these three teeth, is more 

 than half the mastoid breadth, but in arctos considerably less. 

 The sujDerior size of the teeth of pruinosus may be proved by still 

 more comparative measurements, but the samples mentioned may 

 be enough. It is, however, of interest to observe that the teeth 

 of the pruinosus specimen' are not only absolutely and compara- 

 tively larger than those of the typical arctos, but also than those 

 of the big Black Bear from Mongolia, which I consider identical 

 with U. lasiotus Gray (conf. below), and which belongs to the 

 arctos group. This holds good, although this Mongolian Bear is 

 very much larger than pruinosu.s ; and if the comparison between 

 the combined length of the three teeth mentioned and the other 

 dimensions quoted above is repeated with regard to the Mon- 

 golian Bear, the same result is obtained as with arctos. By this 

 it appears to be proved that the difiei'ence between the jjruinosus 

 and the arctos groups is distinct enough in this respect. 



The enormous size of the last premolar, and the molars of the 

 lower ja.w can also be seen from the table of measurements above, 

 so that further comments on this may not be needed. The big 

 Mongolian Bear is also as regards the teeth of the lower jaw, 

 very much inferior to the p>ruinosus. 



As 1}he above-recorded measurements prove, the combined length 

 of 2')^-, '>n^, m^, and 7n^ is considerably greater than half the length 

 of the palate in the adult pruinostis * ; but in the Bears of the 

 arctos group — the big Mongolian one [cf. below) included— the 

 former measurement is even less than half the length of the palate 

 in the adult males. In the latter the combined length of the 



* The much worn teeth of the very old specimen do not give very satisfactory 

 measurements, but the corresponding dimension of the joung animal must be 

 compared with the palatal length of the older one. 



