2 1.2 KANSAS UNIVERSITY SCIENCE BULLETIN. 



This investigator joins issue with me upon ray interpretation 

 of these structures, and states his attitude in the following 

 language : 



"McClung fait grand fond, pour appuyer eon interpretation, sur une forme 

 sp^ciale, la forme en anneau, qui pour lui derive du batonnet Vr»> suppose place" 

 transversalement sur le fuseau, ingt'rt? par son milieu et incurve en dehors jusqu' 

 a rapprochement et soudure de ses extremity. 



"Le chromosome en anneau est en effet tres frequent chez les acridiens; 

 mais il nous a 6tG possible d'en reconstituer l'histoire, grace a des details qui ne 

 semblent pas s'etre rencontres dans les figures de McClung. On se souvient que 

 nous avons <?tabli les deux points suivants en complet disaccord avec la theorie 

 de l'auteur ame>icain: 



"1. Les deux moiti^s de l'anneau proviennent de la premiere division longi- 

 tudinale. 



"2. L'insertion est terminale." 



With equal emphasis, I must deny that the enclosed space in 

 the ring represents any plane of division in the chromatin 

 thread ; and that the insertion of the spindle fibers is at any 

 place except at the center of what would be the typical rod- 

 shaped chromosome were the ring straightened out. We en- 

 counter in de Sinety's interpretation of these rings the very 

 error against which I was careful to caution elsewhere in this 

 paper, i. e., of regarding the points where the fibers are attached as 

 the crossed ends of a simple segment. This mistake de Sinety has 

 made, and has thereby vitiated all his conclusions concerning 

 the structure of the tetrads. It is not necessary to repeat here 

 the proof which I have brought forward in support of my views. 

 No one, I am sure, will find difficulty in reducing the various 

 forms of chromosomes found in the first spermatocytes to the 

 type of a doubly split rod, in which one plane of division is 

 parallel to the long axis and the other at right angles to it. 

 The explanation offered by de Sinety requires us to conceive a 

 doubly split rod in which one separating space may vary indefi- 

 nitely while the other is constant. There is here no common 

 type, but an infinitely variable one, which differs with every 

 modification of the interspace between the first pair of chro- 

 matids in each chromosome. 



As a constructive basis for the foundation of his theory of a 

 double longitudinal division, de Sinety uses particularly the 

 chromosomes of ffidipoda (Hippiscvs) miniata, represented in 

 figures 129 and 130, concerning which he says : 



" Survient le ph^nomene exceptionnellement important de la seconde division 



