2l8 KATHARINE FOOT AND E. C. STROBELL. 



"After this paper was sent to press a notice of our results 

 appeared in the following publications: 'Heredity and Sex,' 

 Morgan ('13), and 'Chromosomes, Heredity and Sex,' Don- 

 caster, Q. J. M. Sci., Vol. LIX. ('14). 



The latter disposes of our results in a footnote, as data irrele- 

 vant to a paper entitled "Chromosomes, Heredity and Sex 

 A Review of the Present State of the Evidence with Regard to 

 the Material Basis of Heredity, Transmission and Sex-Determi- 

 nation." 



From his report of the evidence he draws the following con- 

 clusion: 



"The facts of sex-limited 1 transmission thus support the 

 hypothesis that both ordinary Mendelian factors and the sex- 

 determining factor or factors are borne by chromosomes," p. 511, 

 and in the above-mentioned footnote he adds: "The recently 

 published work of Foot and Strobell cannot be used as an argu- 

 ment against this proposition. They have shown (as was pre- 

 viously known in birds and moths) that a secondary sexual 

 character in Hemiptera can be transmitted through the sex that 

 does not show it; but the character was not sex-limited 1 in trans- 

 mission; their results, therefore, have no bearing in the present 

 discussion." As opposed to this decision we claim that the very 

 fact that the genital spot is not linked with one of the so-called 

 sex chromosomes is a point that calls for a satisfactory explana- 

 tion by those who believe in sex-determining chromosomes, and 

 our results cannot be cancelled by a dogmatic assertion that 

 they have no bearing on the subject. 



Morgan treats the facts with more consideration and attempts 

 to give an explanation of them, though his explanation appears 

 to us more as an attempt to excuse the facts than to explain 

 them. Part of his explanation is merely a restatement of our 

 conclusions, and the remainder is not in harmony with the facts. 



We concluded that our results demonstrate that the spot 

 can be transmitted without the X- or the Y-chromosome and 

 Morgan accepts this as follows, "these results may be explained 

 on the assumption that the factors lie in other chromosomes than the 

 sex-chromosomes. ' " 



1 Sex-limited is used by Doncaster in the sense that sex-linked is used by Morgan. 

 - The italics are ours. 



