42 Inheritauce of Coat-Colour hi Babbits 



Totals ... 16 14 7 25 17 17 7 4 



with animals of the con.stitution ddee. Since no agouti has appeared 

 it must be inferred that dEA gametes (and also Dea gametes) were 

 not formed. Hence it must be supposed that the coupling between 

 D and E is complete, or that if partial, it is of very high intensity. At 

 present we have no gi-ounds for supposing that it is not complete. 



The Chocolate Series. 



In my earlier paper I gave a brief account of some experiments 

 with a chocolate rabbit, for which I was indebted to the kindness of 

 Dr Hagedoorn (loc. cit, p. 235). Further work has confirmed the view 

 that chocolate in the rabbit, as in the mouse, behaves as a simple 

 recessive to black, and that the black series of colours is paralleled 

 by a corresponding recessive chocolate series. Chocolate x yellow 

 gives agoutis in F^, and these agoutis bred together give in F2 

 agouti, black, yt'Uow and tortoise, and also cinnamon, chocolate, dilute 

 cinnamon, and orange — the corresponding colours in the chocolate 

 series. The considerable mass of data accumulated during the past 

 few years amply confirms the view that the chocolate series runs 

 strictly parallel with the black series, diifering from the latter simply 

 in lacking the factor for black (B). 



The relations of the chocolate series to the factor D are however 

 of interest, and may be considered in more detail. A pedigree is 

 given in Fig. 2 in order that the somewhat complicated experiments 

 may be more easily followed. An F^ agouti-black doe of the consti- 

 tution DdEEAa was mated with the chocolate buck received fi-om 

 Dr Hagedoorn. Since her gametic outjjut is DEA, DEa, dEA, dEa, 

 she gave, as was expected, blacks, agoutis, and agouti-blacks, all of 

 which were of course heterozygous for B. The blacks and agoutis 



