102 GERT BONNIEK 



In the experiments reeorded in tlie tables 11, 12, 13 and 15 we have 

 much more clearly del'ind endpoints of the part of the A'. In table 15 

 we have the percentage 8,o from which we find that the length of the 

 part of the X is 18,5 units and that suits the experiment very well since 

 one of the limits of the X lies between scute and eosin and the other 

 between echinus and cut and hence the minimum and maximum 

 length's of the part of the A' used are 4,o and 20,o units. 



Concerning the experiments from tables 11, 12 and 13 the right 

 end of the part of the A used lies to the right of forked and more 

 probably it coincides with the right hand end of the whole chromo- 

 some. From tables 11 and 12 (when taken together) we have the 

 percentage 14,2 which gives us the length of the A' as 49,5 units. In 

 table 13 we have the percentage 13,3 from which the length 45 units of 

 the A is found. 



If we thus suppose that the right end of the part of the A used 

 in these last mentioned tables coincides with the right endpoint of the 

 whole chromosome and if we ijurthermore suppose that in tables 11 and 

 12 the left end of the part of the X lies just at the middle of the loci 

 for cut and vermilion or at 26,5 and that likewise in the experiment of 

 table 13 the left endpoint of the part of A used lies just at the midpoint 

 between vermilion and garnet or at 38,7 then we find the following two 

 values for the total length of the A-chromosome as counted from the 

 locus of scute: 



Total length of the X-chromosome calculated from the data of 

 tables 11 and 12 : 76,o units. 



Total length of the X-chromosome calculated from the data of 

 table 13 : 85,7 units. 



Let us now finally consider the figures from the tables 1, 2, 3 

 and 4. There we have a percentage of 22,3 but as only table 1 shows 

 a percentage higher than this value and all the three oilier tables a 

 percentage lying below it, it seems to be more correct to us? the per- 

 centage from table 2, viz. 21,4 % (of the four tables 1—4 the table 2 

 has also the lowest mean error). But the experiments of these tables 

 concerned higii non-disjunctional femajes i. e. the exceptional females 

 here were homozygous for the whole A. Thus also from these experi- 

 ments it is possible to calculate the length of the whole A-chromosome. 

 The equation for this calculation is 21,4 = 4,3 + 0,2 2 or: The length of 

 the X-chromosome as calculated from experiments with high non-dis- 

 junction : 55,5 units. 



We have thus by means of the equation for the correlation 



