VI REVERSION 6i 



ish ones, and the proportions in which they came showed 

 the Himalayan character to be a simple recessive. A cer- 

 tain number of the coloured forms exhibited the Dutch 

 marking to a greater or less extent, but as its inheritance 

 in this set of experiments is compHcated and has not yet 

 been worked out, we may for the present neglect it and 

 confine our attention to the coloured types and to the 

 Himalayans. The proportion in which the four col- 

 oured types appeared in F2 was very nearly 9 agoutis, 3 

 blacks, 3 yellows, and i tortoiseshell. Evidently we are 

 here dealing with two factors: (i) the grey factor (G), 

 which modifies black into agouti, or tortoiseshell into yel- 

 low; and (2) an intensifjdng factor (/), which intensifies 

 yellow into agouti and tortoiseshell into black. It may 



Yellow X Himalayan 



Agouti X Agouti 



1 1 1 1 1 



Agouti Yellow Black Tortoise Himalavan 

 Shell ^ 



(27) (9) (9) (3) (16) 



be mentioned here that other experiments confirmed the 

 view that the yellow rabbit is a dilute agouti, and the 

 tortoiseshell a dilute black. The Himalayan pattern be- 

 haves as a recessive to self-colour. It is a self-coloured 

 black rabbit lacking a factor that allows the colour to 

 develop except in the points. That factor we may denote 



