R. H. CoMPTON 67 



It seems therefore almost impossible to maintain the hypothesis of 

 somatic segregation of right- and left-handedness in Maize: and despite 

 the negative result of the single experiment on the subject, I incline 

 to embrace the first explanation proposed, viz., that the difference in 

 offspring between odd and even rows is due to the direct influence of 

 spatial relationships on the developing embryo. 



In two-rowed Barley no such dependence upon position was found : 

 it may be suggested that the difference in the case of Maize is due to 

 the close packing together of adjacent rows of seeds ; for in two-rowed 

 Barley the individual seeds develop without lateral pressure from 

 neighbouring rows such as they experience in Maize. 



Genetic Spirals. 



It is not proposed at present to enter fully into the question of 

 genetic spirals from the point of view of ratios and heredity : experi- 

 ments are in progress, and it is hoped to publish a paper on this subject 

 at some future date. Meanwhile it is interesting to remark that the 

 ratio LHjRE, for genetic spirals also, diverges from equality in a more 

 or less marked degree in the cases investigated. Bonnet' found 43 RH 

 and 30 LH stems among a collection of 73 plants of Chicory. Out of 

 458 plants oi Lepidium sativum I found 241 LH and 217 RH. 



Not only is there a divergence from equality in the case of different 

 plants, but on one and the same plant there may be a considerable 

 excess of branches showing one spiral over those showing the reverse 

 one. Valuable data were obtained^ by Dr A. H. Church and Mr E. G. 

 Broome with respect to the genetic spiral of certain individuals of 

 different species of Pines : the following numbers were recorded : — 



Tree 

 P. austriaca 



,, Average 

 P. pumilio 

 P. laricio 



,, Average 



1 Recherches snr Vusage des 

 '- A. H. Church, The Relat 

 1904. 



5—2 



