A. H. Trow 



319 



We have found that certain derivative reduplications are of the form 

 p : q : q : p. It seems probable that there may be primary reduplications 

 also of this type. When such a reduplication is confined to one pair of 

 factors A and B, a third factor C being unaffected, the gametic series 

 would be 



pABC +pABc + (/AbC + ryAbc + 5'aBC + gaBc + iJabC +pa.bc. 

 The diagram would take the form shewn at the bottom of p. 818. 

 If p=q there is no reduplication. If jD is > q, we get coupling; if 

 q is > p, we have repulsion. 



But we may have reduplication between A and B of the form 

 p : q : q : p and between A and C of the form r : s : s : r. In this 

 event there will be a derivative reduplication between B and C, the 

 form of which may be ascertained as follows : — 

 The gametic series will be 



prABC +psABc + qrAbC + qsAhc + qsa.BC + qra.Bc + psabC + pra.bc, 



and, by extracting, the derivative reduplication is found to be 



BC : Be : bC : be :: pr + qs : ps + qr : qr + ps : qs + pr, 



or more simply 



:: p?' + qs : ps + qr : ps + qr : pr + qs. 



This is the most general formula for a derivative reduplication and is of 

 course applicable to all the preceding simpler cases. 



The following diagram illustrates the course of the assumed segre- 

 arations and cell-divisions : — 



qrAhC 



qs Abe 



prABC 



ps ABc 



ABCc 



xp 



abCc 



jsaBC 



fsabC 



pr ahc 



raBc 



