CANI3 FAIIILIAEIS. 1G5 



any two breeds." They also add :— " It becomes apparently a hopeless 

 task to look for evidence as to the proximate or ultimate derivation 

 of the breeds of domestic dogs in their skidls or teeth." 



They have also observed a dozen cases of an additional molar on one 

 or on both sides of the upper jaw in Domestic Dogs. 



Nehring has noted * a Domestic Dog with an additional molar both 

 above and below, and another (a Terrier) in which an inferior molar 

 was deficient, as also a Dingo with five premolars both above and 

 below. 



A deficiency of teeth seems to often acconip.'iiy hairlessness. This 

 was observed by Mr. Yarrell f in two hairless dogs living in the 

 Zoological Society's Gardens, neither of wliicli had any premolars, or 

 the full number of incisors, while one was destitute of canines, and he 

 possessed the skull of a hairless Terrier which had no premolars. In 

 another hairless Dog, which died in the Gardens, ail the teeth were 

 wanting save one molar on either side of either jaw. 



When the muzzle has become shortened in a breed, the teeth, if not 

 deficient in number, become distorted in position J. 



Most remarkable of all these forms is the Japanese Pug-dog, the 

 skull of which, as here given, was originally figured by Dr. Gray ^, 

 who received it from Dr. W. Lockhart. Tliis degraded type has been 

 erected by Cope |i into a new genus and species named " Di/sodes 

 pravus," but we can only regard it as a domestic monstrosity worthy 

 of notice. 



The individual, which was living in England, had slender legs, very 

 long hair, and carried its tail, which was rather bushy, closely curled 

 up over its back. It was mainly fed on vegetable food, being 

 particularly fond of cucumbers. 



* Sitzungsb. d. Gcs. naturf. Freunde Berlin (1882), p. 65. 



t Proc. Zool. Soc. 1833, p. 113. Mr. Yarrell exhibited the specimen referred to 

 " with the view of illustrating the apparent connexion between the hair and the teeth."' 



X Darwin, ' Animals and Plants under Domestication,' vol. ii. p. 345 ; and Windlo 

 and Humphreys, op. cit. p. 28. 



§ Proc. Zool. Soc. 1807, p. 40. 



!| See Proc. Acad. Xat. Sci. PhUadelphia, 1879, pp. 183 & 189, and ' American 

 Naturalist,' vol. xiii. (1879), p. 655. 



