﻿CANIS. 



23 



(4) The length of the upper carnassial pm. 4 is superior or at least equal to 

 that of the molars m. 1 and 2 in wolves, while in dogs the length of pm. 4 is less 

 than, or at most equal to, that of the m. 1 and 2 (Graudry and Boule). 



(5) The plane of the eye-socket is more obliquely inclined to the brow, i. e. the 

 orbito-frontal angle is less in wolves than in dogs (Studer) (see Text-fig. 8). 



(6) The brow is more swollen at the base of the muzzle in dogs (de 

 Blainville). 



(7) The zygomatic arch is less curved and shorter in the wolf (Vieira). 



(8) The coronoid process reaches above the zygomatic arch in the dog but not 

 in the wolf (Vieira). 



(9) The caudal vertebras are more variable in the dog (de Blainville). 

 Denny 1 also refers to the following points : (a) The intermaxillaries (? nasal 



Text-fig. 8.— Anterior view of the skull of a dog, and instrument for measuring the orbito-frontal angle. 



processes of the premaxillse) and nasals are longer and narrower in dogs than in 

 wolves ; (/>) the nasal cavity is wider in wolves ; (c) the orbital projections 

 (probably the post-orbital processes of the frontals) are more acute in dogs ; (d) the 

 jaws are wider ; and (e) the tympanies are larger in wolves. 



The above is a considerable list, but the great majority of the points amount to 

 very little and are quite inconstant and unreliable. 



Probably the most important character is No. 5, for which we are indebted to 

 Studer. 3 The angle to Avhich he alludes can be better realised by the preceding- 

 diagram (Text-fig. 8) than by description. He regards as belonging to wolves, 

 skulls in which the angle between the plane of the orbit and that of the brow 

 measures 40-45°, and as belonging to dogs, skulls in which the angle is greater 



1 'Proc. Yorks. Geol. Polyt. Soc.,' iii, 1857 (1859), p. 538. 



2 ' Abli. schweiz. pal. Ges.,' xxviii, p. 13. 



