314 FERNANDUS PAYNE 



actually observed. But his difficulties do not end here. A 

 thud spermatocyte chromosome is L-shaped. This Voinov be- 

 lieves to be made up of a bivalent and the accessory. It is purely 

 a belief, however, as he offers no proof that such is the case. 

 In division, he believes that the bivalent passes to one end of 

 the spindle and the accessory to the other. As pointed out 

 earlier, this is not the way we would expect such a chromosome 

 to divide, even if it were a bivalent and an accessory. These 

 three spermatocyte chromosomes (the L, XY, and m) account 

 for seven of the 17 spermatogonial chromosomes. 



There are still ten spermatogonial chromosomes to be gotten 

 into four first spermatocyte chromosomes. Voinov does this 

 by assuming that four spermatogonial chromosomes unite to form 

 a large spermatocyte chromosome, which divides regularly. 



Here are four assumptions made by Voinov, which I be'ieve 

 to be needless, as the facts can be explained in an easier and 

 better way. He even attempts to bring my observations on 

 Gryllotalpa borealis in line with his. Voinov's first assumption 

 is that the small spermatogonial chromosome is bivalent and 

 that it forms the m-chromosome of the first spermatocyte. 

 According to my observations on Gryllotalpa borealis the single 

 small spermatogonial chromosome forms the* small end of the 

 unequal pair. This is a perfectly logical conclusion, and we are 

 not forced to assume that the small spermatogonial chromosome 

 is a bivalent and that another small chromosome exists but is 

 invisible. His third assumption is that the L-chromosome :s a 

 bivalent plus an accessory. Such may be the case, but this 

 chromosome divides into two equal parts, a thing which we 

 would not expect it to do if it were composed of a bivalent and 

 an accessory. His fourth assumption is that four spermato- 

 gonial chromosomes fuse to form a large bivalent which behaves 

 regularly. By making these assumptions he gets his 17 sper- 

 matogonial chromosomes (two of which he has not seen) into 

 the seven spermatocyte chromosomes. 



As previously stated my observations on the material col- 

 lected at Naples show there are 15 chromosomes in the sper- 

 matogonial group, and it indicates there are eight first sper- 



