MENDEL'S EXPLANATION 177 



represented the gamete, and the pair the zygote. 

 The single letters at the top of the four-square Table 

 represented gametes, and the pairs in the squares 

 zygotes. 



This Table may now be written in a generalised 

 form in which D and R represent dominant and 

 recessive characters in general. Thus : — 



E 



D 



R 



Another form of such a Table, in which the capital 

 and small sizes of the same letter are used instead of 

 D and R to represent the dominant and recessive 

 characters of a pair, should be referred to here, because 

 it is necessary to use this form of notation in the 

 general form of the sixteen-square Table, which is 

 used to represent the union of gametes of hybrids 

 between forms differing in respect of two pairs of 

 characters. This form of the Table is given on the 

 next page. 



An inspection of this Table, or a casting back of 

 the memory to the counters, will reveal the fact that 

 there are two kinds of zygotes. One is the result 



M 



