STUDIES ON HIGH AND LOW NON-DIS.I UNCTION 



89 



tal)lc 5, hut in order to avoid the production of XXYY females the 

 males were always taken from those cultures of tahle ô in which no 

 exceptions occurred. Unfortunately only three of these females showed 

 themselves to he of the XXY type (tahle 6). As expected there was the 

 low percentage of exceptions in hihles 5 and 6, viz. 2,i5iO,8o and 



2,59 rt 0,69. 



The mother of cult, 462 (tab. G) had Ihe conslitut. — r ^-^ 



and she was crossed to a scute echinus male from culture 450 (tahle 5). 

 A numher of her scute daughters were crossed to wild ty[)e males 

 from stock. Of these daughters those which were not exceptions them- 

 selves (tahle 7) had in both their A':s inherited a part of the original 

 X:s, In one of the X:s they thus carried the whole part of an X which 

 lies to the right of some point between echinus and cut in which in 

 the meanwhile a new lethal had arisen (//, see Bonnieh 1923). The 

 other X was of the constitution .s,- w'' h Ir f or perhaps in some instan- 

 ces Sc w^ h Ir, i. e. of the original X there remained a piece from a point 

 between scute and eosin to a point to the right of tan. Thus finally 

 the section that was common to the two Ä':s and which originated 

 from the Z:s had its endpoints somewhere between echinus and cut 

 and somewhere between tan and forked. Such crosses were continiu'd 

 for some generations where the exceptional females were always picked 

 out. From table 7 we find that in a total of 3588 there was 9,28 + 0,49 

 percent of exceptions. 



The scute forked mother of culture 463 (table 6) had one A' of 

 the constitution s,- /; /;• f and a part of this A' reaching from a point 



TABLE 6. 

 Offspring of regular daughters from table 5, when mated by males 



from the same table. 



Percentage of exceptions 2,.-.9 ± 0,n6. 



