46 A MANUAL OF MENDELISM 



Now it is shown to differ from still another — albino — 

 in another pair ; and, if we call the new pair C and c, 

 the characters now known to be carried by grey and 

 the four colours albino, blue-grey, black, and yellow, 

 which differ from it each in one pair of characters, are : 



Grey XYZC 



Albino XYZe 



Blue-grey XYzC 



Black XyZC 



Yellow xYZC 



But the second table reveals a new phenomenon. 

 The number of groups is not in accordance with the 

 Mendelian scheme. Too many for one pair of characters 

 and yet not enough for two, three groups suggest two 

 pairs of characters and four groups, two of which are 

 inseparable by the eye. If this hypothesis be correct, 

 then, since grey, the largest group in the set, corresponds 

 to one of the original parents, the smallest group in the 

 set should correspond to the other and should be an 

 albino which, by its position in the set, should differ 

 from grey in two pairs of characters. There being a 

 total of 140 individuals in the set, the last group should 

 contain about 9 (140 ^ 16 = 8*75) and the 21 remaining 

 albinos should belong to one of the middle groups and 

 differ from grey in one pair of characters. They should 

 thus be of the kind concerned in the production of the 

 hybrids and progeny enumerated in Table I. Then, since 

 the characters carried by three of the groups are already 

 known, those carried by the fourth may be inferred : 



Grey XYZC 



Albino No. 1 XYZc 



Black XyZC 



Albino No. 2 ? 



