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 leermg 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! 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 Species Bion Maximum Minimum) Average 
| specimens. | . f | angle. | angle. angle. 
| : ; reer <r a 
| (a) 8 | Wolf (recent) | Brit. Mus. 45° | 40° 42° 
| (b) 5 | Dog (prehistoric) _ e |} 53° | 46° 493° 
i) Ce)e2z Dog (recent) | ae i 62° | 45° 504° 
(d) 9 m if | Bristol Wmv: |) tot | 48> ls 
Belonging to each of the first three groups there were, however, certain 
exceptional skulls which 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 (/) had angles of 42°, three skulls in group (c) had angles 
below 45°. 
The angle is not very easy to measure even with a clmometer such as is shown 
in the figure, and it was found that when the same skull was measured on different 
occasions shghtly 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 
rehability 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. Roy. Irish Acad.,’ xxxiii, B., pt. 1, p. 208. 
