ORTHOPTERAN SPERMATOGENESIS 715 



e. Movements of chromatids. Whole univalent chromosomes 

 are separated bodily by this form of division, according to the 

 explanation of Montgomery, Davis and Buchner, but because 

 of his conception of a double longitudinal division, de Sinety sees 

 in it an equation division. The evidence against this has already 

 been given and will not be repeated here. 



/. Relation of chromosomes to spindle poles. According to de 

 Sinety and those who follow him, there is described a most unique 

 movement of the chromosomes involved in the ring. Instead 

 of passing to the spindle pole toward which they lie, they cross 

 over to the opposite side. All explanations of cell division, which 

 involve an element of organization finding expression in the bi- 

 polar condition of the cell parts at this time, are controverted 

 by such a process. I feel convinced that there is no such condi- 

 tion of the chromosomes and I do not believe that the reported 

 twisting of the chromosomes in the metaphase described for many 

 forms, particularly plants, is correct. As a pure matter of obser- 

 vation I am sure that it does not occur in the Orthoptera. Per- 

 haps the appearance of the looped or double ring chromosomes in 

 many species of this order has been responsible for the error. 

 By the interpretation of de Sinety (figs. 124 and 125), Brunelli 

 (fig. 15) , Buchner (fig. 42) , Davis (figs. 184 and 185) these are merely 

 twisted rings. Although occasionally such conditions are met 

 in the prophase the forms that later appear in the metaphase are 

 not thus constituted. At this time the second ring, the one 

 further removed from the center of the equatorial plate, will 

 always be found to lie perpendicular to the primary ring and to 

 merge symmetrically into it. If these were really twisted rings 

 they would commonly lie more nearly in the same plane and the 

 outer loop would not enter into the inner symmetrically. When 

 prophase structures, corresponding to those of the metaphase, 

 are studied it is found that the secondary ring is really produced 

 by the further development, at the contrasynaptic ends, of occa- 

 sional divergences of the chromatids of the same character as the 

 ones found commonly at the synaptic ends; and these may even 

 go so far as to start the production of a third ring in the same 

 plane as the primary one. In other words, the chromatids do 



JOUHNAL OF MORPHOLOGY, VOL. 25, NO. 4 



