1S90.] ON THE DOMIlSTIC DOG. 



Measurements. — Dental. 



25 



upon the skulls, and cause differences in breeds which cannot be 

 accounted for, is, of course, to be e5;pected. The presence of the 

 disturbing factor can be aj)preciated, though its exact nature cannot 

 always or even frequently be ascertained with any correctness. 

 Thus amongst the eleven Bull-dogs' skulls which we have exam- 

 ined there was one •which differed in measurements considerably 

 from the rest. It was nearly 1 cm. longer than any other and, 

 what is much more significant, it was 7 cm. longer than it was 

 broad, the average for tlie others being about 3 or 4 cm. Moreover 

 its palate was l^yOcm. longer than it was broad, whilst in every 

 other case but one the breadth exceeded the length. In the 

 second case, the length was '90 greater than the breadth of the 

 palate, and the length of the skull nearly 5 cm. greater than the 

 zygoma'ic width. VA'^e hope to be able to show more fully in another 

 part of this paper tliat the first effect of impurity in breeding upon 

 an artificially broadened and shortened skull; uch as the Bull-dog 

 possesses, is in the direction of elongation and narrowing. We can- 

 rot douht that both of the skulls above mentioned were those of 

 dogs in whom, to a greater or lesser degree, there was an admixture 

 of strain, of what kind it is impossible to say. ,\nd what is true of 



