I08 Hagedoorn. 



E, and more like that produced by lack of H in some combinations 

 in mice as well as in rabbits and cavies. The dilute (dd) colours in 

 rabbits are identical with those in mice. In rabbits there exist 

 animals which are truly blue like blue mice or cats, dilute agoutis 

 with exactly the colour of dilute agouti mice, and silverfawn, of thie 

 same colour as mice. In cavies the colours called dilute by Miss 

 SOLLAS are certainly not due to the absence of this same factor d. 



I can say so with certainty, for I have bred cavies which lacked 

 the factor D, and had the constitution ABCdEFGH. These had exactly 

 the same colour as dilute agouti mice or rabbits. The factor studied 

 by Miss Sollas is identical to one studied by Plate and me in mice, 

 and which I will call H. In my records I find 366 young born from 

 couples of which one parent was Dd and the other dd. Of these young 

 172 had the factor D, being Dd; the remaining 194 being dd. The 

 expected ratio was 183 : 183. 



Evidence for the independance of this factor D from the factors a, 

 B, c, E, G and H can be found in the appended tables. Nos 3, 4, 5, 

 7, 9, 10, 12 and 14 on the coloured plate do not contain D, all the 

 others have it. 



Factor E. 



E is another of the four factors D, E, F and H, necessary for full 

 pigmentation. It has been extensively studied by Miss Durham, and 

 somewhat by Darbishire. The first mice lacking this factor were 

 without any doubt imported from Japan, where, as a former resident 

 tells me, pink-eyed coloured waltzing mice are commonly bred. 

 Darbishire was, I believe, the first to use this material for crossing- 

 experiments, and he invented the name "Lilac" for the colour 

 ABCDeFgH, (N" 8) Under which name it is now bred by fanciers. 

 Absence of this factor E makes that the eye remains less pigmented 

 than normally. Its presence or absence affect the colour of the coat, 

 but only appreciably so when D is present. In yellow mice (bb) such 

 as I bred, presence or absence of E produces hardly any effect on the 

 colour of the coat, although the animals can at once be distinguished 

 by their eye-co our. Black (ABCDEFgH) (No 15) become lilac, (ABCDeFgH) 

 when E is absent, its presence or absence makes the difference between 

 chocolate (ABcDEFgH) and champagne (ABcDeFgH), between cinnamon 

 (ABcDEFGH) (No i) and pink-eyed cinnamon (ABcDeFGH) (N" 11). 



The mice called "gelb -grau" and "gelb-silbern" by Plate are pink- 

 eyed forms. I do not believe he ever bred true black- eyed yellows. 



