Chap. III. THEIR VARIATION. 71 



appearance from the pigs of the S. scrofa type, so that they 

 must be considered specifically distinct, it is a fact well de- 

 serving attention, that Chinese and common pigs have been 

 repeatedly crossed in various manners, with unimpaired fertility. 

 One great breeder who had used pure Chinese pigs assured me 

 that the fertility of the half-breeds inter se and of their recrossed 

 progeny was actually increased; and this is the general belief 

 of agriculturists. Again, the Japan pig or S. pliciceps of Gray 

 is so distinct in appearance from .all common pigs, that it 

 stretches one's belief to the utmost to admit that it is simply 

 a domestic variety ; yet this breed has been found perfectly 

 fertile with the Berkshire breed ; and Mr. Eyton informs me 

 that he paired a half-bred brother and sister and found them 

 quite fertile together.. 



The modifications of the skull in the most highly cultivated 

 races are wonderful. To appreciate the amount of change, 

 Nathusius' work, with its excellent figures, should be studied. 

 The whole of the exterior of the skull in all its parts has been 

 altered ; the hinder surface, instead of sloping backwards, is 

 directed forwards, entailing many changes in other parts; 

 the front of the head is deeply concave; the orbits have 

 a different shape ; the auditory meatus has a different direc- 

 tion and shape ; the incisors of the upper and lower jaws 

 do not touch each other, and they stand in both jaws above 

 the plane of the molars; the canines of the upper jaw stand 

 in front of those of the lower jaw, and this is a remarkable 

 anomaly : the articular surfaces of the occipital condyles are 

 so greatly changed in shape, that, as Nathusius remarks (s. 

 133), no naturalist, seeing this important part of the skull by 

 itself, would suppose that it belonged to the genus Sus. 

 These and various other modifications, as Nathusius observes, 

 can hardly be considered as monstrosities, for they are not in- 

 jurious, and are strictly inherited. The whole head is much 

 shortened ; thus, whilst in common breeds its length to that of 

 the body is as 1 to 6, in the " cultur-races " the proportion is as 

 1 to 9, and even recently as 1 to 11." The following woodcut 16 



1 5 < Die Racen des Schweines,' s. 70. excellent edition of « The Pig ' by 

 is These woodcuts are copied from Youatt, 1860. See pp. 1 16 19 ' 

 engravings given in Mr. S. Sidney's 



