40 hihentance of Coat-Colour In Rabbits 



TABLE I. 



Blacks ex agouti-black x agouti-black. 



F 188 X choc, gave 4 black 

 i'' 189 „ ,, 2 „ 



JF190 „ „ 7 ,, 



i^l94 „ „ „ 



F198 ,, „ 6 ,, 



■F199 „ „ 4 „ 



-^212 ,, „ 3 „ 



F 213 ,, „ 5 „ 



F 93 ,, ,,4 black H- 5 agouti-black 



F 94 „ „ 4 „ +1 



DDaa^ 

 Ddaa I 

 ddaa I 



DDAa 



F2(il „ „ 4 „ +1 



-^215 „ „ 1 „ +2 „ j 



i^217 „ „ 4 „ +2 „ ) 



F238 „ „ 10 agouti-black DDAA 



a normal black in appearance. This deduction, which could only be 

 assumed in the earlier account {Jourii. Gen. 1912, p. 230), is now 

 confirmed by direct experiment. 



It was previously pointed out that agouti-blacks must, on the 

 hypothesis put forward, be always heterozygous for D. In addition 

 to the eight F., rabbits already tested and shewn to fulfil this condition 

 (Journ. Gen. 1912, p. 233), five F, agouti-blacks {F 8^, F 85, F 94, 

 F 104, and F 150) from agouti-black parents have also been tested. 

 In each instance the animal was shewn to contain A and to be 

 heterozygous for D. 



These further results all served to confirm the view jjreviously 

 advanced, and the chief remaining point of interest was to determine 

 whether the coupling between the factors D and E must be regarded 

 as complete, or whether it is of the nature of a partial coupling of 

 high intensity. For this purpose a number of rabbits of the consti- 

 tution DdEeAA were bred (see .Tourn. Gen. 1912, p. 233) and mated 

 with animals containing neither D nor E. The appearance of a few 

 agoutis from such matings would indicate that the coupling was 

 partial. The facts obtained are shewn in Tables II and IIP. 



Some further data are also given from the matings of four does 

 of the constitution DdEeAa (Table IV). If the coupling between 



1 A few of the data given in Tables II — IV have already been recorded (Journ. Gen. 

 1912, pp. 233, 234). The bulk of them however are new. 



