COLOR 



53 



YELLOW TYPE. 



(9) Yellow (with white belly and tail), same as i, with R (restricted) 

 substituted for E (extended black or brown pigmentation), namely, 



B. 



Br' 



R 



(zo) Cream (i. e., dilute yellow), same as 9, with D substituted for I. 

 (n) Spotted yellow, same as 9, with S substituted for U. 



(12) Spotted cream, same as 10, with S substituted for U. 



(13) Sooty (yellow with pigmented belly and tail), same as 9 without 



A, or as 5 with R substituted for E, namely, 

 U ^B, 



R 



(14) Pale sooty, same as 13, with D substituted for I. 



(15) Spotted sooty, same as 13, with S substituted for U. 



(16) Spotted pale sooty, same as 14, with S substituted for U. 



WHITE TYPE. 



(17) White (wholly unpigmented) , in any of the foregoing 16 varieties 



with C omitted. 



(18) Himalayan white, a pink-eyed albino variety differing from 17 in 



appearance, in having black pigmented extremities (nose, ears, 

 feet, and tail) and in having fur of a creamy white, not of a snowy 

 white as in 17. Those with which we have experimented seemed 

 to be of the formula 1 



That is, they were black pigmented rabbits (see 5) in all points except C. It 

 would seem that we must assume the presence of C in some form in an animal 

 which like these does bear a certain amount of pigment. Nevertheless this C 

 is not the same as the C found in dark-eyed pigmented varieties, for a cross of 

 Himalayan with other albinos produces no dark-eyed offspring, and gives no 

 increase of pigmentation over that found in the Himalayan parent, but rather a 

 diminution of it (see Castle, 105). If, then, we assume C to be present hi the 

 Himalayan, it must be in a greatly modified form, as compared with its condi- 

 tion in dark-eyed animals. This is why we use C' rather than C in the formula. 

 The factors E, I, and U, were all found to be present in our Himalayan rabbits, 

 but not A, for crosses of Himalayan with homozygous gray gave only gray in 



1 April, 1909. Himalayan rabbits have now been produced which contain also factor A. They 

 have extremities less heavily pigmented than ordinary Himalayans, and the tail is white 

 underneath, as in gray and in yellow rabbits. 



