W. Bateson and R. C. Punnett 301 



2. If in the gametes of auy plant some factors are distributed 

 according to one of the reduplicated series and other factors according 

 to the normal Mendelian system — as we know they may be — the segrega- 

 tions by which such a system is brought about cannot liave happened 

 simultaneously. Moreover if various reduplications can take place very 

 early in some individuals and not in others, we cannot imagine how the 

 normal form of the plant remains unchanged, unless these reduplications 

 afifect tissues originally set apart as germinal. 



As possibly significant we note here the fact that in the embryonic 

 development of plants the order of the various divisions is known to 

 be subject to great variation and it is not inconceivable that such 

 disturbances of the order in which the planes of division occur may 

 indicate variations in the process of segregation^ 



3. We do not yet know whether independent reduplicated systems 

 can be formed in the same individual. In the sweet pea for instance 

 we have not yet seen the consequences of combining blue, erect standard, 

 and long pollen with the fertile-sterile, dark-light axil series, and much 

 may be discovered when such families come to be examined. 



Animals. 



The phenomena seen in animals may well be produced by the 

 segmentations in which the parts of the ovary or testis are determined. 

 Hitherto no case of coiipling has been found in animals. Among the 

 phenomena of repulsion, however, of which many examples exist, certain 

 suspicious cases have been observed which may mean that in animals 

 reduplicated systems exist like those of the plants. Nevertheless at 

 present it seems not impossible that the two forms of life are really 

 distinguished from each other in these respects. 



Terminology. 



Lastly, in view of what we now know, it is obvious that the terms 

 " coupling " and " repulsion " are misnomers. " Coupling " was first 

 introduced to denote the association of special factors, while "repulsion" 

 was used to describe dissociation of special factors. Now that both 

 phenomena are seen to be caused not by any association or dissociation, 

 but by the development of certain cells in excess, those expressions 



1 See Coulter and Chamberlain, Morphology of Angiosperms, 1903, p. 187. 



