30 DOGS. Chap. L 



different breeds, living in various parts of the world, makes the fact 

 highly remarkable. 



We shall hereafter see, especially in the chapter on Pigeons, that 

 coloured marks are strongly inherited, and that they often aid us 

 in discovering the primitive forms of oui* domestic races. Hence, 

 if any wild canine species had distinctly exhibited the tan-coloured 

 spots over the eyes, it might have been argued that this was the 

 parent-form of nearly all our domestic races. But after looking at 

 many coloured plates, and through the whole collection of skins In 

 the British Museum, I can find no species thus marked. It is no 

 doubt possible that some extinct species was thus coloured. On 

 the other hand, in looking at the various species, there seems to be 

 a tolerably plain correlation between tan-coloured legs and face ; 

 and less frequently between black legs and a black face ; and this 

 general rule of colouring explains to a certain extent the above- 

 given cases of correlation between the eye-spots and the colour of 

 the feet. Moreover, some jackals and foxes have a trace of a white 

 ring round their eyes, as in C. mesomelas, C. aureus, and (judging 

 from Colonel H. Smith's drawing) in C. alnpex, and C. thaUh. 

 Other species have a trace of a black line over the corners of the 

 eyes, as in C. variegatus, cinei-eo-variegatus, and fulvus, and the wild 

 Dingo. Hence I am inclined to conclude that a tendency for tan- 

 coloured spots to appear over the eyes in the various breeds of 

 dogs, is analogous to the case observed by Desmarest, namely, that 

 when any white appears on a dog the tip of the tail is always white, 

 " de maniere a rappeler la tache terminale de meme couleur, qui 

 caracterise la plupart des Canides sauvages."*^ This rule, however, 

 as I am assured by Mr. Jesse, does not invariably hold good. 



It has been objected that our domestic dogs cannot be 

 descended from wolves or jackals, because their periods of 

 gestation are different. The supposed difference rests on 

 statements made by Buffou, Gilibert, Bechstein, and others ; 

 but these are now known to be erroneous ; and the period is 

 found to agree in the wolf, jackal, and dog, as closely as could 

 be expected, for it is often in some degree variable.*^ Tessier, 



*' Quoted by Prof. Gervais, ' Hist. three days, for she received the dog 



Nat. Mamm.,' torn. ii. p. 66. more than once. The period of a 



*^ J. Hunter shows that the long mongrel dog and jackal was fifty-nine 



period of seventy-three days given by days. Fred. Cuvier found the period 



Buffon is eisily explained by the bitch of gestation of the wolf to be (' Diet, 



having received the dog many times Class. d'Hist. Nat.' torn. iv. p. 8) two 



during a period of sixteen days (' Phil. months and a few days, which ai^rees 



Transact.,' 178.7, p. 353). Hunter with the dog. Isid. G. St.-Hilaire, 



found that the gestation of a mongrel who has discussed the whole sutiject, 



from wolf and dog (' Phil. Transact.,' and from whom I quote BelliQgeri, 



1789, p. 160) apparently was sixty- states ('Hist. Nat. Gen.,' torn. iii. p 



