290 APPENDICES. 



also favored me with a European skull, No. 6564, from the 

 Smithsoaian Institution.^ 



By comparing the skulls of this extensive series with the de- 

 scriptions given by Brandt in the following article, I find that 

 many more resemblances may be traced between the European 

 and the American beaver than he has observed, thus reducing the 

 amount of constant differences between the two varieties. 



We give the translation of the whole of his article in which 

 the two kinds of skulls are compared, adding to the sections the 

 results obtained by an examination of the skulls of the American 

 series referred to above. 



"Memoires de I'Academie de St. Petersbourg, VI. Serie, p. 53. 



" § 1. Superior aspect of different beaver skulls. 



" If we examine the skull of the European and of the American 

 beaver, we notice the following special differences: 



" 1 . The portion of the frontal bone lying between the arches of 

 the eyebrows, in all the European skulls is shorter and broader, 

 much broader than long; but in the American, narrower and 

 somewhat longer (quite as broad as long) ; so that the middle 

 transverse diameter of the anterior portion of the frontal bone — 

 that part lying between the eyes — is in the American skulls 

 nearly or quite as long as the arch of the eyebrows ; but in the 

 European it appears longer than this." 



This is true generally of the American skulls ; but in six speci- 

 mens the average length of the eyebrow portion is 81"'f, and 

 the average width of the middle portion is 1'' 08"'^, being an 

 excess of width of 26"'|. 



" 2. In the European skulls the arches of the eyebrows are 

 shorter, and their posterior tubercles, opposite the highest point 

 of the malar bone, are strongly developed. In the American, on 

 the contrary, the posterior eyebrow processes, only indicated, 

 sometimes scarcely indicated at all, or at least but slightly devel- 

 oped, can be seen back of the highest point of the malar. The 

 anterior eyebrow process is in all the European skulls likewise 

 stronger than in the American." 



The highest point of the malar in American skulls is in advance 

 of the posterior processes; but in one skull (No 20) it is on a line 



1 I am also indebted to Prof. Baird for the use of several works, relating 

 to the beaver, from the Smiihsonian Institution. 



