356 Varietäten, Descendenz, Hybriden. 



Harris, J. A., A quantitative study ofthe facto r sin fluen- 

 cing the weight of the bean seed. II. Correlation be- 

 tween number ofpods per plant and seed weight. (Bull. 

 Torrey Botan. Club. XLIII. p. 485-495. 4 Fig. 1916.) 



This paper presents eonstants showing the degree of correlation 

 between the weight attained by the individual seed and the number 

 of pods per plant. 



The correlations are positive throughout the t wen ty-seven series 

 for which data are available, but are of a low order of magnitude 

 and highly variable. The}^ ränge from -j- .005 to -j- .339 with a 

 mean of + -159 ± .012 and an absolute variability of .092 + .008. 



In both average magnitude and variability the correlations for 

 seed weight and number of pods per plant are in excellent agree- 

 ment with those for number of ovules per pod and number ofpods 

 per plant and with the correlation for number of seeds per pod and 

 number of pods per plant. 



The average value of the correlation for pods and weight is 

 lower than that for pods per plant and ovules per pod and higher 

 than that for pods per plant and seeds per pod, but both of these 

 differences are low, and may not be significant in comparison with 

 their probable errors. Jongmans. 



Jennings, H. S., Heredity, Variation and theresults of selec- 

 tion in the uniparental reproduction of Difflugia Corona . 

 (Genetics. I. p. 407—534. 1916.) 



The contents of this paper may be summarized us follows: 



The rhizopod Difflugia Corona shows a number of very definite 

 characters that are congenital, not modified by growth, and not 

 affected by the environmental conditions during the life of the 

 individual; these are therefore remarkably favorable for studies of 

 inheritance. These characters are: The number ofthe spines on the 

 shell; the length of these spines; the diameter of the shell; the 

 depth of the shell; the number of teeth surrounding the mouth; the 

 diameter of the mouth. 



In a population found in nature the individuals differ among 

 themselves with respect to all these characters. The different sets 

 of characters of the individuals are statistically correlated, in such 

 a way that in large populations an increase in any one of these 

 characters is accompanied on the average by an increase in the 

 others. When a population is allowed to propagate, the characters 

 of the parent are inherited in a high degree by the progeny. Coeffi- 

 cients of correlation between parent and progeny rise even to 9 

 with respect to some of the characters. The parent-offspring corre- 

 lation for given characters is diverse in different populations. 



Following the pedigrees of descendants of given individuals, 

 the populations are found to consist of many hereditarily diverse 

 strains. The heritable characteristics of any given strain or family 

 show a high degree of constancy through many generations, though 

 the individuals within the strain may differ greatly in their personal 

 characters. If two diverse strains are compared, the}^ remain con- 

 stantly diverse trough many generations. The different strains show 

 hereditary diversities with respect to all the six sets of characters 

 enumerated above; also with respect to the way these characters 

 are combined. A strain that shows one of the sets of hereditary 

 characters in a higher degree (for example a large number of spi- 



