191 



would, in my opinion, be sheer nonsense for me to use the formuhi 



b I b 



for a tetrad whose four component chromosomes according to my 

 account are all unlike one another. 



Thus we have seen that either of Wilson's proposed substitutes 

 for my formula would, if adopted, render the account self-contra- 

 dictory. If we should adopt the formula ^, each spermatid could 

 receive but 3 chromosomes, whereas each spermatid actually receives 6. 

 If we adopt the formula t4-t this implies a longitudinal splitting 



which I claim does not take place in Caloptenus. The proposed 

 formulas, therefore, instead of obviating difficulties and self-contra- 

 dictions, as Wilson asserts, only serve to introduce such contradictions 

 and to create glaring inconsistencies, which do not exist in the ori- 

 ginal account. 



The account which I gave of the spermatogenesis of Caloptenus 

 differs in some respects from most other accounts of the spermato- 

 genesis of animals. In accordance with nearly all spermatologists I 

 found a doubling of the normal number of chromosomes in the pro- 

 phases of the first maturation division. But this doubling, I main- 

 tained, was, in Caloptenus, not due to a longitudinal splitting of the 

 chromosomes. In the spireme of spermatocytes of the first order the 

 chromosomes were described as arising separately and independently 

 of one another. The chromosomes then became associated in pairs 

 the individuals of which are held together by linin threads. 



Later the pairs by conjugation form tetrads. The four components 



of a tetrad are therefore all unlike one another and the formula ,— ^- 



b I b 



could certainly not be used for such a tetrad. 



We have, moreover, no right to assume that a doubling of the 

 chromosomes necessarily implies a longitudinal splitting. Wagnek 

 ('92) indicates that such a splitting is not necessary to a doubling of 

 the chromosomes. Godlewski ('97) saw no longitudinal splitting in 

 Helix. If, as I maintained in the case of Caloptenus, no splitting is 

 to be observed, and the chromosomes arise by an aggregation of the 

 minute chromatic granules into a definite and constant number of 

 chromatic bodies or chromosomes, no two of these bodies can be 



assumed to be qualitatively identical, and the formula -^-jy for a tetrad 



composed of four such chromosomes is out of the question. The 

 dumbbell-shaped bodies of which I have spoken are not, as Wilson 



