G. \v. i)i-:i.rx n.\ ML KIT. 



shortened until the locus of translocation is reached. In this 

 interval, between ebony and rough, the per cent, of crossing o\ IT 

 is less than one third that of the normal. Between rough and 



I7S 



U5 



l&H. 



7* 



so 



IS 



st 



ss 



HOMOZYGOUS TRANSLOCATION 



173 

 150 



125 



75 



SO 



ru 



st 



ss A H 



ro 



Cd 



HETEROZYGOUS 



TRANSLOCATION 



FIG. 2. Chart showing the ratios (in percentages) of the observed crossover 

 values to the standard. The abscissa represents the length of the III. chromosome 

 from roughoid to claret; the ordinate represents the percentage which the observed 

 crossovers form of the standard value in each region. The heavy line represent- 

 the percentage observed; the dotted lines mark the limits of the probable error 

 of this percentage, calculated for eacli interval. 



claret the amount of crossing over rises again, approaching half 

 the normal value. Tin- number of flies involved was not large 

 enough to yield reliable data on the coincidences, but as far as 

 they went they agreed well with the normal. 



