INSEPARABLE EFFECTS 41 



But, irrespective of this result and however found, 

 cream was shown to be the colour carrying the characters 

 xYz by being mated with black ; for their hybrids' 

 progeny consisted of the eight colours each approxi- 

 mately in the proper number, namely : 



And, since black carries the characters XyZ, there is 

 only one combination of characters, namely, xYz, with 

 which it can be mated and have hybrids which when 

 mated together produce eight colours. Thus cream 

 must carry the characters xYz, and, the only combina- 

 tion left for pale tortoise-shell being xyz, the complete 

 set of eight colours consists of : 



