316 



Forms of RedujMcation 



Nos. found 



Expectation on ratio of 5 : 3 : 3 : 5 derived from 



SG Sg 

 64 35 



sG sg 

 30 44 



7:1:1:7 

 2:1:1:2 



5i 



32 



32 



54 



The suggestion of the 2:1:1:2 ratio in tlio secoiul case is made 

 on my own responsibility — Gregory does not assign one. The main 

 interest lies in the fact that the derivative ratio 5:3:3:5 explains 

 fairly well the facts of the case. 



The following diagram will serve to illustrate the hypothetical course 

 of the segregations and the cell-divisions in this case. 



14MSG 



2MsG 



7msG 



?MSg 



2mSg 



y^msg 



The sign x signifies increase in the number of gametes, or gameto- 

 genic, segregating cells, and the following number the relative amount 

 of increase along the different axes. 



The primary and secondary reduplications, three in number, are 

 notable in that each represents a case of coupling. Let us therefore 

 consider the case in which the primary reduplications are of the form 

 1 : n : n : 1 for A and B and 1 : iii : ni : I for A and C. Under these 

 conditions the gametic series will be 



ABC + wiABc + «AbC + niiiAbc + nmaBC + )(aBc + j/iabC + abc, 



and the reduplication between Band C will be found (by extracting) to 

 be of the form 



BC : Be : bC : be :: 1 + iiiii, : in + n : n + m : nin + 1. 



We thus get the result that the reduplication between B and C is 

 of the same form whether the ratios between A and B and A and C 



are 



1 : n : n : 1 and \ : m : m : 1 or n : 1 : 1 : n and in : 1 : 1 : m. 



