No. 586] THE INHERITANCE OF D UBLENES S 



635 



makes both sin files and doubles heterozygous (Ss); 11 the 

 former assumption, however, is also excluded, as Miss 

 Saunders shows, by the fact that all singles tested pro- 

 duce some doubles when pollinated by doubles — that is, 

 the expected class of pure singles (SS) does not occur. 

 Evidently, as both Goldschmidt (1913) and Belling (1915) 

 assume, 12 doubleness is dominant in Petunia, and selective 

 viability probably completes the explanation. 



BIBLIOGRAPHY 



Bateson, William. 



1909. Mendel's Principles of Heredity. 14 + 396 pp. Cambridge, 



Univ. Press. 6 pi. and 37 fig. 

 1914. The Address of the President of the British Association for the 



40: 287-302. 

 Bateson, William, and Punnett, E. C. 



1911. On Gametic Series Involving Reduplication of Certain Terms. 

 Jour, of Genetics, 1: 293-302, 1 pi. and 1 fig. 



1915a. Conditions of Mendelian Inheritance. Jour, of Heredity, 6: 108. 

 East, Edward M. 



1915. The Phenomenon of Self-sterility. Am. Nat., 49: 76-87, Bibliog. 

 Francis, Myrtle Shepherd. 



1913. A New Creation in Floriculture. The Rural California)). 37: 



ii Tn the dihybrid scheme, here, if linkage is to be invoked, as in Matthiola, 

 to explain the deviation from 50 per cent, of doubles, both the singles and 

 the doubles must 'carry both factors— since the singles possess both by 

 hypothesis, and we are supposing the pollen of the doubles to show linkage! 

 Further, doubles, not singles, would be expected to be in excess of 50 per 

 Petunia. ' e t d b d scheme seems to be possible with 



