MENDEL'S EXPLANATION i8i 



forms are reproduced in the next generation in equal 

 numbers. In No. 3, one parental form, the recessive, 

 is not reproduced at all. In No. 4, where the two 

 parents, the hybrids, are similar, they only account 

 for a half of the next generation, the remaining half 

 being made up of the grand-parental dominants and 

 recessives in equal numbers. 



This extremely simple feature of matings, Nos. 5 

 and 6, is also characteristic of the inheritance of 

 sexual characters ; the result of the union of a male 

 with a female is the production of equal numbers 

 of males and females on the average. And this fact, 

 which the founders of the Mendelian theory have, 

 until recently, neglected, has become the corner-stone 

 of the Mendelian theory of the inheritance of sex, 

 and will also, in my opinion, play a very important 

 part in elucidating the origin of the Mendelian mode 

 of inheritance. 



These two tjrpes of mating may now be dealt 

 with separately. No. 5 is represented on the four- 

 square Table as follows : — 



(5 gametes 

 D K 



D 



09 



a 



Of 



D 



