300 MK. c. c. iiuiiaT : kxperimental studies 



down the flanks on each side, the yellow becomes more diluted, 

 passing from tan through fawn, buff, and cream to white under 

 the tail and belly, where the yellow pigment is not evident. In 

 the same way the black portions of the hairs, both basal and 

 apical, become diluted, passing from dense black through blue- 

 black, slate-grey, and grey -white to white. 



This dilution of the black pigment is especially noteworthy in 

 the roots of the hairs, giving the impression of a blue-black 

 ground-colour close to the skin, when the hairs are blown aside. 

 A certain amount of chocolate or brown pigment appears to be 

 always associated with the black. 



Amongst the parti-coloured yellow and black hairs which go to 

 form the grey coat there are a few long black hairs scattered more 

 or less regularly, especially along the back and loins and on the 

 ears and foreliead. These long black hairs give a wavy appear- 

 ance to the coat, known to fanciers as "ticking" ; they are more or 

 less shaded with brown, have blue-black roots, and do not usually 

 appear until about the age of two months. 



The above observations show that the hairs which make up the 

 grey coat of the wild rabbit contain at least two distinct pigments — 

 yellow and black, with their dilutions ; and most probably a third, 

 brown or chocolate, which is more or less evident in close associa- 

 tion with the black pigment. {Gf. Mr. Bateson's, Miss Durham's, 

 and Dr. Allen's observations on similar pigments in Mice : Bateson, 

 1903 ; Allen, 1904.) 



The yellow-grey coat of the Belgian rabbit used in these experi- 

 ments contains the same pigments, and is in all respects similar 

 in nature to that of the wild grey, except that it contains a larger 

 proportion of yellow pigment and less black in the individual 

 parti-coloured hairs in all parts of the coat. This increase of 

 yellow and reduction of black appears to affect the basal part 

 of the hairs more than the tips. 



Further, the bright tan-yellow, which is usually confined to 

 the space behind the ears in the wild grey, is extended to the 

 chest and flanks in the yellow-grey, though this also shades off, 

 downward and backward, through fawn, buff, and cream, to white, 

 as in the wild grey. The creamy-white hairs borne underneath 

 in tlie wild grey have blue-black roots, giving them a grey-white 

 appearance ; while those of the yellow-grey in the same place have 

 apparently no trace of the diluted black pigment, being almost 

 pure white. The long black hairs also appear to be less in number 



