1862.] DR. J. E. GRAY ON THE JAPANESE PIG. 17 



1 . Face smooth, or nearly so ; skull conical ; the upper part of 

 the nose rounded ; palate narrow. Sus. 



Sus scrqfa, Sus indicus, Sus vittatus. 



2. Face deeply and symmetrically furrowed ; the skull flattened 

 on the forehead ; the upper part of the nose flattened, keeled on the 

 sides ; palate broad. Centuriosus. 



Sus pliciceps. 



I regard the facts contained in this paper as very interesting — first, 

 as adding a new kind of domestic animal to our list (and I do not 

 thijak that any has been added since the introduction of the Turkey 

 from Mexico) ; and secondly, as showing, from a domestic animal, that 

 there must be a wild species which has not yet been brought into our 

 catalogues. 



I may observe that, like many other very distinct species of cer- 

 tain genera of domesticated or semi-domesticated Mammalia, as the 

 Horse, Ass, and Zebra, the Ox, the Dog, &c., the fact of inter- 

 breeding is no proof that a kind is not a species ; for no one would 

 argue that an Ass and a Horse are the same species, or a Zebra 

 {vnd Quagga, or vice ve7'sa. 



The Japanese Pig breeds with facility with the common domestic 

 Pig. We have not had time to observe whether the offspring is 

 prolific. The half-breed of the Japanese Boar with a common Sow 

 retains almost all the external characters of the male parent well de- 

 veloped. I have not yet had the opportunity of observing what 

 effect the crossing has on the osteological characters of the species. 



I think that no one who will take the trouble to compare the 

 skulls of the different varieties of domestic Pigs which are usually 

 found in England, vrith the skull of the European Wild Boars and 

 the Wild Pigs of Asia and the Island, can doubt for a moment the 

 derivation of the domestic breeds from the wild type*. Indeed, the 

 change in form is so slight as to be scarcely perceptible, and the 

 gradation between the most abnormal form to the wild animal so gra- 

 dual as to be sufficient to show that even the most abnormal state is 

 due only to a gradual change of form. 



Mr. Eyton, in a paper printed in the ' Proceedings,' has shown that 

 a Chinese Pig which he examined had a different number of vertebrae 

 from another domestic Pig ; but the skull of a Chinese Pig I have 

 examined shows no characters to separate it from the Common Pig. 

 Its head is a little shorter than usual, but not so short as that of a 

 Berkshire Pig. 



* See Bartlett, Proc. Zool. Soc. 1861, pp. 263, 26-1; Ann. and Mag. N. H. 

 1861, 501 ; 1862, 162. 



Proc. Zool. Soc— 1862, No. II. 



