476 E. ELEANOR CAROTHERS 



7. All of these types of heteromorphic homologues segregate 

 at random in the first maturation division. 



8. Considering the J-shaped tetrads alone, of sixty-two males, 

 two formed sixty-four morphologically different sorts of sperma- 

 tozoa, seven formed thirty-two sorts, ten formed sixteen, twenty 

 formed eight, twenty-one formed four and only two were di- 

 morphic. 



9. The complex is constant in the individual for somatic, 

 spermatogonial and first spermatocyte metaphases and has a 

 fixed range of variation for the second spermatocytes. Certain 

 exceptions to this general rule have been noted in the text, e.g., 

 the accessory with numerous fibers attached (plate 7, 45) and 

 the tetrad which divides unequally in Circotettix (plate 10, 70). 



10. The complex varies widely in the group within the limits 

 of the above mentioned types of heteromorphism, indicating, 

 so far as my material goes, that random mating of the various 

 classes of morphologically different gametes has occurred. 



11. Taxonomically the group is exceedingly variable. 



IV. DISCUSSION 



1. Constancy in individuals 



To me one of the most impressive facts in this whole work has 

 been the very great degree of individual constancy of the complex 

 which has been preserved in the organism in spite of the wide 

 range of morphological variation between the homologous chro- 

 mosomes in these species. It should be emphasized that the 

 term individual constaticy is applicable here, although it is 

 used in a broader sense than is ordinarily the case; that is, while 

 the somatic, spermatogonial and first spermatocyte complexes 

 are practically identical for the respective generations in a given 

 individual, there is a fixed number of morphologically different 

 classes of second spermatocytes for each individual, but in all 

 cases these can be calculated from a knowledge of the first sper- 

 matocyte complex. 



It is futile to speculate at present on the cause of this hetero- 

 geneity, but so far as the doctrine of chromosome individuality 



