LÖNNBERG, STUDY OF THE VARIATION OF EUROPEAN BEAVERS. 3 



remarks may be of value for the understanding of the varia- 

 bility of the arrangement of the enamel folds of the Beaver. 

 The Beaver hke the greater number of the mammalian 

 species belonging to the Scandinavian fauna have entered 

 their present habitat from Denmark after the Ice-age and 

 therefore it is of some importance to consider the structure 

 of the molars of the now extinct Danish Beaver. It was 

 therefore of great interest to me to find a molar af a Danish 

 Beaver figured in the recently published valuable work ^ on 

 the Mammals of Denmark by Herluf Vinge. On this figure 

 the inner enamel fold is quite opposite to the anterior one 

 of the outer side, thus an arrangement which by Matschie 

 has been ascribed to the Elbe Beaver. It could then be 

 expected that, if this was a valid characteristio, the Danish 

 Beaver belonged to the same race as the Elbe Beaver. For 

 the purpose of obtaining full and decisive information 

 about this I took the liberty of writing to Mr. Vinge asking 

 him whether the molar pattern exhibited on the quoted figure 

 constituted a distinct characteristio found in all Beaver skulls 

 from Denmark. Mr. Vinge kindly favoured me with the 

 following: »Den Baever, hvis Hovedskal og övre m^ jeg har 

 af biidet, har de paagjeldende modstaaende Emailleslynger 

 kun paa m^ og w}, ikke paa p^ og m^ hvor Slyngerne skyde 

 förbi hinanden. Forholdet er hos vore jordfundne B^vere 

 (jeg eftersaa i dag 14 Hovedskaller) vildt vexlende», (in trans- 

 lation : »The Beaver the skull and upper m^ of which I have 

 figured has the debated enamelfolds opposite each other 

 only on m^ and m^ not on p'^ and m^ in which the folds 

 shoot past each other. The condition is in our subfossil 

 Beavers (I examined to day 14 skulls) ivildly variable.) This 

 evidently settles the matter as far as the Danish Beavers 

 are concerned as some of the molars of the same specimen 

 belong to the »Elbe type» and some.others to the »Swedish 

 type». It could, however, be objected against these facts 

 that at that time when the Danish Beavers in question lived, 

 the differentiation of a northern (Swedish and Norwegian) 

 and a southern (Elbe) race had not yet taken place and that 

 therefore the characteristics of the Danish Beavers could 

 still be vague or mixed. As there might be some reason for 



' Herluf Vinge: »Pattedyr» N:o 5 af »Danmarks Fauna». Copen- 

 hagen 1908. 



