Wilson — Unsound Mendeliun Developments. 419 



Their second crosses will be represented as follows : — 



C B S = Black, splashed . 27 

 C B p = Black, plain . . 9 

 C bl S = Blue, splashed . . 9 

 a B S = Black albino, splaslied 9* 

 a bl S = Blue albino, splashed 3* 

 a B ]} = Black albino, plain . 3* 

 C bl p = Blue, plain . . 3 

 a bl p = Blue albino, plain . 1* 



The different albinos (*) cannot, of course, be distinguished from each 

 other by the eye. 



(iii) From two white kinds of sweet pea. Professors Bateson and Punnett 

 were able to extract six kinds of coloured sweet peas whose colour-factors the 

 whites had been carrying without their effects being apparent.' From these 

 six coloured kinds the white factors were eliminated and the coloured kinds 

 bred and observed separately. The point to be noticed is that there are six 

 groups : an unusual number. Is there something wrong with the Mendelian 

 formulae, or are tliere really more than six groups or less ? 



The first crosses from the two whites were a purple flower with blue 

 wings. The second crosses were purples and reds in the ratio 3:1. Thus 

 purple is dominant to red. But the purples on the one hand, and 

 the reds on the other were subject to a set of parallel variations. The 

 first-cross purple had bluish wings; and this same kind appeared in the second 

 crosses with two others, of which one had its wings darkened from bluish to 

 purple, while the third was a dilute form of the first. Corresponding to 

 these were a red with lighter wings, a red with red wings, and a dilute form 

 of the first. 



Taking the purples as the example, the ratios in which the three kinds 

 appear are purple with bluish wings, 9 ; purple with purple wings, 3 ; dilute 

 purple, 4. If the Mendelian formulffi be correct, we have here a set of four 

 groups in which the two last are not separated. The formula to meet the 

 case is 



Purple with bluish wings. Purple with purple wings. Dilute purple. Dihite purple. 



9 3 3 1 



X X XX 



Y y Y y 



Where X is carried the colour is dense; where x is carried it is dilute, and 

 the densing factor is dominant to the diluting. Where Y appears the colour 



' Punnett, pp. 74, &c., and Bateson, pp. S3, &c. 



