244 PROP. HUXLEY ON THE CRANIAL AND [Apr. 6, 



The prfemolar teeth are smaller in C, azai'ce ; but as they are more 

 worn it is difficult to make an exact comparison. The upper sectorial 

 is not quite so long as that of the Fox. The transverse diameter 

 is the same in front, but is less behind, in G. azarce ; and its inner cusp 

 is less forward in position and less prominent. The lower sectorial is 

 narrower and the anterior internal cusp somewhat larger in C. azarce. 

 In both, a line drawn from the anterior-external to the anterior- 

 internal cusp (a b, fig. 3, p. 243) makes an acute angle with, a trans- 

 verse line, on account of the not very backward position of the latter. 

 In the Fox there is a very small secondary cusp between the inner 

 anterior and the inner posterior cusps, which is absent in G. azarce. 



The second lower incisor lies completely behind the first in C. 

 azarce ; but this is probably only an individual exaggeration of a 

 tendency to the displacement of the second incisor backwards, which 

 is often observable in the Canidee. 



Table II. — Measurements of the Cheek-teeth ofC vulpes and 



C. azarse. 



C. vulpes. C. azarm. 

 Length of the whole upper prsemolar 



and molar series 54 50 



Length of the whole lower praemolar 



and molar series 00 57 



Length of ^^^* 13 12-5 



'^ 9-3 9 



Breadth of — - 11 11 



Length of '^^^— 5 5 



Breadth of — 7*3 7 



Length of — ^ 15 143 



» ^ 7-3 -5 



3 3-5 



>i 



m. 3 



In both G. vulpes and C. azarm the hinder ends of the nasal 

 bones just reach the level of the hindermost part of the fronto- 

 maxillary suture. In the Fox the ascending processes of the })r8e- 

 maxillary bones reach the anterior processes of the frontal bones, 

 while in C. azarce there is a wide interval between the two. 



In both, the temporal ridges unite into a crest for a short distance 

 behind ; but for the rest of their extent they are separate, inclosing 

 a very narrow sagittal area (fig. 1, p. 241). At the anterior ex- 

 tremity of this the ridges diverge and pass outwards to the angles of 

 the supraorbital process ; and it is at this point that the principal 

 external difference between the two skulls becomes apparent. 



In the Fox (fig. 1, B, p. 241), the well-defined ridge runs nearly 

 parallel with its fellow for some distance in front of the coronal suture, 

 and then sweeps outwards, in a sharp curve, to the recurved supraorbital 

 process, behind which a deep constriction marks the boundary between 



