No. 535] 



NOTES AND LIT FEATURE 



423 



in those cases of undoubted prepotency, which are of the greatest 

 interest and importance both theoretically and practically, 

 wherein the prepotent individual does not itself have the char- 

 acter with regard to which it is prepotent expressed in its own 

 soma. An example here is the dairy bull, prepotent in respect 

 to milking qualities. 



A continuation of this work on peas is reported in the second 

 paper by the same authors. Data are presented showing the 

 relation between observed variability and environmental (sea- 

 sonal) conditions. The interesting point is brought out that 

 there is less variation, and a higher correlation between parent 

 and offspring, in respect to vine length, than in respect to either 

 number of pods per vine or total peas per vine. 



Roemer gives a very detailed biometrical study of pure lines 

 in peas. The work is essentially a confirmation, with another 

 plant, of Johannsen's epoch-making investigations on beans, 

 though it lacks any extensive studies on the effect of selection 

 within the pure line. The essential objective point of Roemer 's 

 research is rather to determine the biometric characteristics of 

 pure lines as such in relation to the general population. Among 

 the more important general results are the following : 



1. The different biotypes in a population arrange themselves 

 in frequency distributions in accord with Quetelet's law. 



2. No relation was found to exist between the variability of 

 the biotypes {%. e., variation within the general population) and 

 variation within the pure lines. 



Shaw has made a very thorough biometric study of variation 

 in the Ben Davis variety of apples and presents a mass of data 

 of considerable general biological interest. When one recalls 

 that commercial apple varieties are propagated by vegetative 

 processes entirely, the importance of a careful study of this varia- 



