Wilson — Simplified Solutions of Certain Mendelian Problems. 487 



But the cliaracters carried by blue and tortoiseshell can also be determined. 

 Blue is recessive to both blue-grey and black, and therefore differs from each 

 in one pair of characters. Thus it carries one dominant less. This dominant 

 cannot be Z, for then blue would differ from blue- grey in three pairs of 

 characters. Nor cau it be I", for then blue would differ from black in three 

 pairs of cliaracters. It can only be X, and the characters carried by 

 blue are therefore Xyz. For similar reasons the characters carried by 

 tortoiseshell must be xi/Z. Thus the complete set of eight with the colours 

 so far identified as belonging to six of the possible combinations is 



The two unfouud colours could be found by mating blue-grey with 

 tortoiseshell or yellow with blue.' 



The same conclusion is arrived at by the same line of argument as that 

 previously taken with the mice. The six colours found cau be arranged in 

 two sets of four groups each. In a set of four groups the largest is dominant 

 to both the intermediate groups, and each of these is dominant to the smallest. 

 By this method of identification the two sets become, with provisional 



By being at the top of two sets, grey must carry three dominants at least, 

 and perhaps four. But, since black appears in both sets, grey cau carry only 

 three, for if it carried four the characters of grey and black would be XYAB 

 and XyaB, and then the two colours would differ from each other in more 



' It is probable that blue-grey and blue are merely different names for the first two colours in a 

 set of four found by Professor Punnett and called by him cinnamon, chocolate, dilute cinnamon and 

 orange. (Journal of Genatios, Nov. 1912.) In that case dilute cinnamon and orange would bear 

 the characters xTz and xyz. 



