﻿24 



PLEISTOCENE MAMMALIA. 



than 45°. The effect of this greater obliquity of the plane of the orbit in the 

 wolf is to produce the " oblique leering eye which gives the wolf a false expression 

 as compared with the noble, trustful expression of a dog, whose eye, with rounder 

 opening, is more directed forwards." He remarks that if we look at a wolf's or 

 jackal's skull from above, more of the orbit is visible than in a dog's skull. 



The reliability of this distinction, which is accepted by Scharff 1 and used in 

 discriminating the canine skulls from the Edenvale caves, has been to some extent 

 tested by examination of skulls at the British Museum and at Bristol with the 

 following results : 



Number of 

 specimens. 



Species. From 



Maximum 

 angle. 



Minimum 

 angle. 



Average 

 angle. 



(a) 8 

 (6) 5 



(c) 27 



(d) 9 



Wolf (recent) 



Dog (prehistoric) 



Dog (recent) 



Brit. Mus. 

 Bristol Univ. 



45° 

 53° 

 62° 

 54° 



40° 

 46° 

 45° 

 48° 



42° 

 49f° 

 50i° 

 51|° 



Belonging to each of the first three groups there were, however, certain 

 exceptional skulls Avhich are not included in the above table. Thus two additional 

 wolf skulls belonging to group (a) gave angles of 47° and 48° respectively, two 

 dog skulls in group (b) had angles of 42°, three skulls in group (/;) had angles 

 below 45°. 



The angle is not very easy to measure even with a clinometer such as is shown 

 in the figure, and it was found that when the same skull was measured on different 

 occasions slightly varying results were sometimes obtained. 



The measurement was in each case taken over the ends of the post-orbital 

 processes of the frontal and jugal. 



Though it can hardly be claimed that the results of the measurement of the 

 fifty-six skulls referred to in the above table afford a complete test of the 

 reliability of the orbito-frontal angle as a distinguishing character between dogs 

 and wolves, they certainly confirm Studer's contention that the angle tends to be 

 decidedly less in the wolf than in the dog, and that it affords a useful distinction of 

 practical value. The occurrence, however, of dog skulls with an angle of less 

 than 45°, and of wolf skulls with an angle of over 45°, shows that the distinction 

 is not absolute, and cannot be relied on in all cases. 



The second point, that of the origin of the domestic dogs, is the subject of a 



most voluminous literature. It is beyond the scope of the present memoir and no 



attempt can be made to discuss it. The different opinions which have been 



maintained are, however, briefly the following : Daubenton and Cuvier were 



1 ' Trans. Koy. Irish Acad.,' xxxiii, B., pt, I, p. 203. 



