KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 58- N:0 2- 23 



It is also of interest to note that the skulls with raised eyebrow-ridges (thus 178, 

 224, and 160) a t the same time have a considerably narrower interorbital septum than 

 the others. There appears consequently to exist a correspondence between these cha- 

 racteristics. 



The variation with regard to the teeth is of two different kinds viz. partly an evi- 

 dently individual anomaly conspicuous by the presence of supernumerary niolars, and 

 partly a variation in size of the molars. The former anomaly, although interesting in itself , 

 cannot, of course, be of any taxonomic value, but will be described further below, the 

 latter again exhibits differences which are analogous to such as often are used for di- 

 stinguishing different races, or even species. 



If the measurements of the molars of the f emales as recorded in the table are exam- 

 ined, we find at the first look that two females viz. n:o 178 (Pl. VI, fig. 2) and n:o 224 

 (Pl. VI, fig. 4 a) have much smaller molars than the others (f. i. Pl. VI, fig. 4 b). These 

 two females have somewhat smaller skulls and have also a narrow interorbital space and 

 the superciliary ridge raised above each orbit but with a mesial concavity. There is, 

 however, a third female (n:o 160) with such superciliary ridge, verv large orbits andcom- 

 paratively narrow interorbital space, and that one has large molars. There is thus no cer- 

 tain correlation between small molars on one hand, and a doubly arched superciliary 

 ridge and a narrow interorbital septum on the other hand. Nordothe characters mentio- 

 ned standin correlation to the colour of the fur as one of the' small-toothed, n:o 224, is the 

 blackest, and the other, n:o 178, is the greyest among the females. 



In the two males as well the molars are considerably different in size. But in this 

 case the small-toothed specimen (163) has at least not narrower interorbital space than 

 the large-toothed. Thus, although the differences in certain cases, for instance with 

 regard to the breadth of the interorbital space, and the size of the molars, certainly are 

 great enough to appear to be of distinguishing value between different races the lack of 

 correspondence, as set forth above, upsets every attempt of separating these specimens 

 in two racial groups, as for instance a large-toothed and a small-toothed. 1 In spite of all 

 differences it appears impossible for the present but to regard all as individual variations 

 of one and the same race. This is of very high interest as very seldom wild mammals 

 from one and the same place vary in such a remarkable degree. 



If not the molars generally, but one of them is compared in the different specimens 

 a similar result is obtained. It is best to use m n for this comparison as it is most variable 

 and at the same time it is smaller than the first and second true molars. A look at the 

 table of measurements above, in which the breadth of m 3 is recorded, proves that this 

 dimension varies not a little. The greatest interest is, however, connected with the fact 

 that this variation appears to be rather independent of the size of the other molars. Thus 

 the female n:o 181 is decidedly large-toothed, but its m? are among the smallest. The 

 general shape, and the number and size of the cusps are also variable characteristics, but 

 seemingly independent of others. The normal outline of the crown of m 3 is, of course, 

 more or less square, but in n:o 181 it is rounded. Normally there ought to be four cusps, 



1 Such an animal as n:o 160 could in such a ease only be explained as a hybrid! 



