DIFFERENTIAL DEVELOPMENTAL MODIFICATION. I 185 



to a different temperature when both lots reconstitute at the same tem- 

 perature (Behre, 1918). Some effects on head frequency of temperature 



TABLE 6 

 Alteration of Head Frequency by KCN (Dngesia dorotocephala) 

 Fifty pieces in each lot; lots a and c with same Roman numeral are from the same an- 

 imals; frequencies in percentages. 



and temperature-conditioning are shown in Table 7. Low temperature 

 before and after section determines a much lower frequency in a-pieces 

 than medium temperature before and after section (lai, Ilai), but only 

 slightly lower in c-pieces (Ici, IIci). Pieces from animals conditioned to 



