298 APPENDICES. 



lines long, is in all the European skulls lying before me larger, 

 deeper, and more rounded, and inclosed by rounded margins, pos- 

 teriorly particularly strongly curved, so that it appears three to 

 four lines deep, six to eight lines long, and posteriorly six to 

 seven lines broad. In the same skulls we find it more or less 

 widened back of its middle portion, while in the American skulls 

 it appears smaller in comparison with its breadth, longer and 

 narrower, not widened back of its middle point ; at its posterior 

 end even more or less narrowed ; and possesses, in addition to 

 its more lengthened form, nearly straight margins and less depth. 

 Its longitudinal diameter is about six lines, its greater transverse 

 diameter four to five lines, and its depth two and a half to three 

 lines." 



Brandt has well described the basilar cavity as it appears in 

 the American, compared with the European beaver. Its form, 

 however, in the American beaver, is subject to variation, being 

 sometimes narrow and shallow, with its lateral borders nearly 

 parallel, and in some cases it is more rounded — its length and 

 breadth being equal — thus presenting an approximation to the 

 European variety. 



" The posterior processes of the inner sphenoidal wings pro- 

 ceeding to the osseous bullae of the temporal bone, are in all the 

 European shorter, and therefore the bullae of the ossa temporum 

 are moved further forward than in the American." 



The European beaver skull before me presents the peculiarity 

 named above, and the difference between the two varieties in this 

 respect, is confirmed by my observations. 



" The palate bones vary in the European and American skulls, 

 both in length and breadth, as well as in the greater or less 

 acuteness of their anterior extremity. In both there are skulls 

 in which they agree or vary more or less." 



Having but one European skull, I can only state that the 

 palate bones in this skull, and in an American skull before me, 

 agree perfectly in form, and in the position of the palatal fora- 

 mina. There is undoubtedly some difference among American 

 skulls as to the posterior width of the palate bones. The palatal 

 foramina are sometimes opposite the space between the second 

 and third molars, sometimes a little anterior to this. 



" The malar arches often appear in the European beaver thicker, 

 but in manv individuals no thicker than in the American." 



