A THIRD SEX-LINKED LETHAL FACTOR IN 

 DROSOPHILA 



T. H. MORGAN 



Department of Zoology, Columbia University 



THREE FIGURES 



In an experiment (reported in the Jour. Exp, Zool., page 390, 

 November, 1911) in which three sex-hnked characters were in- 



ERRATUM 



F.,r figure 20 read figure 19, and for figure 19 read fijrure 20, pa,e 2(K), vol 

 17, number 2. August, 1914, The Journal of Experimental Zooloo.. 



wxx Kiiio uaaia, tiie resuiDS oi tne previous experiment in terms of 

 cross-overs would be as follows : 



Total Per cent 



Non-cross-overs (vermilion and ver. pink males) 333 74.7 

 Single cross-overs between white and vermilion 



(min. and min. pink males) 81 18 . 2 



Single cross-overs between vermilion and min. 



(verm. min. and ver. min. pink males) 11 2.4 



Double cross-overs (wild type and pink males) ... 21 4.7 



Instead of giving fewer double cross-overs than singles, accord- 

 ing to expectation, the number of doubles was twice that of singles, 

 and for numbers as large as these this difference cannot be due to 



1 In the analysis on page 392 the large C in 'sperm no X' should be small c . This 

 change adds eight classes to the white males and eliminates the same number from 

 the colored classes. The expected numbers in the male classes at the top of page 

 393 should read downwards : 3-3-1-1-8-3-3-1-1-8. 



315 



THE JOURNAl OF EXPERIMENTAL ZOOLOGY, VOL. 17, NO. 3 

 OCTOBER, 1914 



