GERM CELLS OF GRYLLOTALPA 315 



matocyte chromosomes instead of seven. If such be the case, 

 the same explanation holds here as in Gryllotalpa borealis. 

 Two of the spermatogonial chromosomes, unequal in size con- 

 jugate to form the unequal pair. The L-chromosome is an 

 ordinary bivalent, the single unpaired chromosome remains 

 single, and the other ten spermatogonial chromosomes pair two 

 by two to form the five bivalents. This explains all the facts 

 without making any assumptions. Further, my conclusions in 

 Gryllotalpa borealis are backed by the oogonial counts which 

 show 24 chromosomes, none of which are small. 



A paper by Wenrich has also just been received. 4 I wish 

 merely to call attention to his postscript added after having 

 read Voi'nov's preliminary paper on Gryllotalpa. I quote as 

 follows : 



Unfortunately I had overlooked the results reported for Gryllotalpa 

 vulgaris by Voi'nov ('14), who found in the first spermatocyte meta- 

 phase an unequal pair of dyads, which separate so that sometimes the 

 larger dyad and sometimes the smaller one goes to the same pole as 

 the accessory chromosome. These results are in accord with those 

 mentioned above for the Acrididae and the Tettigidae and it may be 

 surmised that similar conditions perhaps obtain for Gryllotalpa borealis 

 but have so far been overlooked. 



My reason for quoting this is to show how readily Wenrich 

 accepts Vo'inov's observations and interpretations, without any 

 hesitation or study, because they fall in line with his own work, 

 and at the same time how readily he discards my own because 

 they do not agree. I believe that my figures in the present 

 paper will be convincing to any one who will take the trouble 

 to study them with an unprejudiced mind. Because certain 

 results agree or disagree with our own preconceived ideas, is no 

 reason for accepting or rejecting them. It seems to me it is 

 time we were realizing that evolution in chromosomes as morpho- 

 logical units, in chromosome numbers, and in chromosome behav- 

 ior has been as diverse as it has been in external morphological 

 characters. It would be about as logical for me to conclude that 



4 The spermatogenesis of Phrynotettix magnus with special reference to 

 synapsis and the individuality of the chromosomes, Bull. Mus. Comp. Zool. 

 Harvard, vol. 60. 



