38 DOGS. Ohap. I. 



from, each other, and remembering Cuvier's admission that 

 their skulls differ more than do those of the species of any 

 natural genus, and bearing in mind how closely the bones of 

 wolves, jackals, foxes, and other Canidae agree, it is remark- 

 able that we meet with the statement, repeated over and 

 over again, that the races of the dog differ in no important 

 characters. A highly competent judge, Prof. Gervais, 73 

 admits " bi Ton prenait sans controle les alterations dont 

 chacun de ces organes est susceptible, on pourrait croire qu'il 

 y a entre les chiens domestiques des differences plus grandes 

 que ce les qui separent ailleurs les especes, quelquefois meme 

 les genres." Some of the differences above enumerated are 

 in one respect of comparatively little value, for they are not 

 characteristic of distinct breeds : no one pretends that such 

 is the case with the additional molar teeth or with the number 

 of mamma; ; the additional digit is generally present with 

 mastiffs, and some of the more important differences in the 

 skull and lower jaw are more or less characteristic of various 

 breeds. But we must not forget that the predominant power 

 of selection has not been applied in any of these cases ; we 

 have variability in important parts, but the differences have 

 not been fixed by selection. Man cares for the form and 

 fleetne-s of his greyhounds, for the size of his mastiffs, and 

 formerly for the strength of the jaw in his bulldogs, &c. ; 

 but he cares nothing about the number of their molar teeth 

 or mammae or digits ; nor do we know that differences in 

 these organs are correlated with, or owe their development 

 to, differences in other parts of the body about which man 

 does care. Those who have attended to the subject of 

 selection will admit that, nature having given variability, 

 man, if he so chose, could fix five toes to the hinder feet of 

 certain breeds of dogs, as certainly as to the feet of his 

 Dorking fowls: he could probably fix, but with much more 

 difficulty, an additional pair of molar teeth in either jaw, in 

 the same way as he has given additional horns to certain 

 breeds of sheep ; if he wished to produce a toothless breed of 

 dogs, having the so called Turkish dog with its imperfect 



" 'Hist. Nat. des Mammif.,' 1855, torn. ii. pp. 66, 67. 



