232 KATHARINE FOOT AND E. C. STROBELL. 



one of the chromosomes consistently fails to divide in the second 

 spindle. It has been said of the accessory chromosome that in 

 the spindle in which it is heterotropic, it tries to divide, but does 

 not succeed. In the case of Anasa tristis, we have demonstrated 

 that it is by no means always unsuccessful in these efforts. 



We regret that we cannot agree with Professor Wilson as to 

 the value of the support he believes he has received from Lefevre 

 and McGill's paper on Anasa tristis and Anax junius ('08). In 

 this paper our results in Anasa are summarily disposed of in two 

 pages of curt contradictions, supported by ten sketches made 

 from sections. The futility of such methods as opposed to the 

 very full demonstration we have given in 107 photographs to sup- 

 port our conclusions in Anasa, must be apparent to any unpre- 

 judiced observer. 



In this same paper, McGill corrects her earlier observations on 

 Anax junius on three very important points : 



1. In her first work on this form ('04) (in which she ex- 

 presses her indebtedness to Professor Lefevre) she found no 

 evidence of a chromatin nucleolus in the resting spermatocyte. 

 She and Lefevre now find, in t/ie same material, a chromatin 

 nucleolus persisting through the resting spermatocyte. 



2. In her earlier work McGill identified the microchromo- 

 some as the accessory chromosome. She and Lefevre now 

 identify, in the same material, one of the larger spermatogonial 

 chromosomes as the accessory chromosome. 



3. In her original count of the spermatogonial chromosomes, 

 McGill found an even number, 28. She and Lefevre now find in 

 the same material an odd number, 27 spermatogonial chromo- 

 somes. 



In view of these contradictions we may justly hesitate to accept 

 as definitive the recent conclusions reached by McGill and Le- 

 fevre in Anasa tristis, believing a new point of view may give us 

 still further variations in their very interesting observations. 



BIBLIOGRAPHY. 

 Arnold, George. 



'08 The Nucleolus and Microchromosomes in the Spermatogenesis of Hydro- 



philus piceus (Linn.). Arch. f. Zellforschung, Bd. II., Hft. I. 

 Deton, Willy. 



'08 L'etape Synaptique dans Povogenese du Thysanozoon Brocchii. La Cel- 

 lule, t. XXV. 



