352 Menders Experiments 



From the wrinkled yellow seeds 96 resulting plants bore 

 seed, of which : 



28 had only wrinkled yellow seeds aB 



68 wrinkled yellow and green seeds aBb. 



From 108 round green seeds 102 resulting plants fruited, 



of which : 



35 had only round green seeds Ab 



67 round and wrinkled green seeds Aab. 



The wrinkled green seeds yielded 30 plants which bore 

 seeds all of like character ; they remained constant ab. 



The offspring of the hybrids appeared therefore under 

 nine different forms, some of them in very unequal numbers. 

 When these are collected and co-ordinated we tind : 



38 plants with the sign AB 



The whole of the forms may be classed Into three 

 essentially different groups. The first includes those with 

 the signs AB, Ab, aB, and ab : they possess only constant 

 characters and do not vary again in the next generation. 

 Each of these forms is represented on the average thirty- 

 three times. The second group includes the signs ABb, 

 aBb, AaB, Aab : these are constant in one character and 

 hybrid in another, and vary in the next generation only 

 as regards the hybrid-character. Each of these appears on 

 an average sixty-five times. The form AaBb occurs 138 

 times : it is hybrid in both characters, and behaves exactly 

 as do the hybrids from which it is derived. 



If the numbers in which the forms belonging to these 

 classes appear be compared, the ratios of i, 2, 4 are un- 

 mistakably evident. The numbers 32, 65, 138 present very 

 fair approximations to the ratio numbers of 33, 66, 132. 



The developmental series consists, therefore, of nine 

 classes, of which four appear therein always once and are 

 constant in both characters; the forms AB, ab, resemble 



