238 Dr. J. E. Gray on the Varieties of Dogs. 



1. By the variation in the character of the hair, as to 

 whether it is short and smooth, or longer, soft and curly, or 

 stiff and harsh or bristly. 



2. By the colour of the skin and the fur that covers it. 

 These variations are to be found in almost all the varieties 



produced by a different proportion of the parts : thus there 

 are smooth curly-haired, and rough-haired greyhounds ; and 

 it is the same with other varieties. 



At the same time, not only can the desired difference in the 

 proportion of the parts, but also the colour and kind of hair 

 be perpetuated by careful breeding and weeding. 



The second kind of variation ought rather to be called ab- 

 normalities or physical defects, though they are continued by 

 breeding and weeding for special purposes, and are even car- 

 ried to such a great extent as to be absolute deformities. The 

 principal of these are : — 



1. The short and more or less bandy legs of the turnspit 

 and lurchers, which are common to terriers and spaniels. 



2. The more or less imperfect development of the upper 

 jaw, found in the bull-dog, pug-dog, and different breeds of 

 spaniels. 



3. The great development of the ball of the eyes, so as to 

 become too large for the orbit and exceedingly prominent and 

 liable to accident, found in some breeds of spaniels and 

 terriers. 



4. The more or less complete want of hair, which is gene- 

 rally accompanied by a more or less complete want or great 

 imperfection in the develornnent and rooting of the teeth, 

 showing the relation between these two organic productions. 



F. Cuvier, in his article on the Dog, projjoses to arrange 

 them into three groups, according to a difference in the pro- 

 portion and position of the parietal and other bones, which 

 arrangement is followed by Youatt, in his essay on dogs ; 

 but the characters are very indefinite ; and I find there is very 

 little difference in the form and character of the skulls of the 

 normal varieties of dogs : they only differ a little in the length 

 and comparative and absolute width of the nose. Indeed it is 

 very difficult to find the slightest difference between the skulls 

 of dogs that are very different in external appearance. 



In what I am more inclined to call monstrosities than varie- 

 ties, such as the bull-dog, which is characterized by the mal- 

 formation or imperfect development of the upper jaw, the 

 skull varies according to the extent of the deformity. It is 

 the same with the large-eyed breeds of spaniels and terriers. 



The skulls of these animals also differ from one another in 

 the completeness or imperfection of the ossification — some 



