664 C. E. McCLUNG 



ment in the spermatogonia is at the end of the chromosome and 

 when they join in pairs these ends are in contact, so that in the 

 first spermatocyte the tetrads have the form of Vs with the 

 same orientation to the spindle as in the previous generation 

 (figs. 32-58). In Stenobothrus however there are median and 

 subterminal attachments and these are the same in both generations 

 of spermatocytes as in the spermatogonia (figs. 59-76). 



(4) Occasionally there are peculiarities of behavior which are 

 constant and uniform. In Hesperotettix there is a union between 

 the accessory chromosome and one of the tetrads. The members 

 of this combination are always identical and their union never 

 fails. Moreover in different species the proportionate size of 

 the parts varies in comformity with the structure of the body. 

 Thus figure 79 shows the condition in H. speciosus, figure 80 in 

 H. viridis and figure 81 in H. pratensis. In Brachystola, as Miss 

 Carothers has discovered, there is a pair, the members of which 

 are unequal, and this is a constant condition accompanying their 

 separation in the first spermatocyte. In Phrynotettix Mr. D. H. 

 Wenrich has found an unequal pair also, one member of which 

 is distinguishable from the other by its granular condition in 

 the metaphase. In this case however the reduction division 

 occurs in the second spermatocyte. This element in the first 

 spermatocyte is shown in figures 88 to 91 and will be described 

 in detail by Mr. Wenrich. 



Supporting in every way these observations upon Orthopteran 

 cells is the consistent background of similar facts in other groups 

 of animal and plants and the significant parallel between their 

 behavior and character development in breeding experiments. 

 The persistence of individual chromosomes in multiple complexes 

 of giant cells and heterospermized eggs is conclusive evidence of 

 their real individuality and continuity. There are many other 

 facts of this character to demonstrate the individuality and mor- 

 phological continuity of the chromosome, but for the present 

 purpose these will serve to show the foundation for my belief 

 regarding them. 



