77 



the axis of the spindle but with a well marked transverse constriction, 

 must be considered a variation from the normal. 



Hence Paulmier is quite correct in his conclusion that the se- 

 cond reduction division is an equation division. But it is nevertheless 

 interesting to note that in the genus Euchistus it may be occasionally 

 transverse, as the figures in my preceding paper show, and as I hope 

 to be able to prove by further examples in a following contribution. 

 Accordingly, my interpretation of the mitotic stages is at fault, and 

 not my description of them, since after finding indubitable cases of 

 the second division being a transverse division, I concluded that in all 

 cases it is transverse. 



In the genus Anasa, on which Paulmier worked especially, the 

 relations are much clearer than in Euchistus, since I have found in 

 some cases that the chromosomes are undoubtedly quadripartite in the 

 equatorial plate of the first spermatocyte, — cases where each chromo- 

 some is not only transversely but also longitudinally cleft, while in 

 Euchistus the longitudinal split cannot be seen at this stage. By the 

 study of a greater amount of material, and by the use of the iron hae- 

 matoxylin stain, I find in Euchistus that the chromosomes in the telo- 

 phase of the spermatogonic division are longitudinally split : this split 

 could not be seen in the preparations which formed the basis of my first 

 papers, owing to the fact that in them the stain was to deep. And these 

 later studies have shown also, that in the spermatogonic divisions the 

 chromosomes are undoubtedly longitudinally split (a point which I 

 had not decided positively) , and that occasionally in the dyaster stages 

 of the spermatogonic and first spermatocytic divisions, as well as of 

 the second spermatocytic division, a "Zwischenkörper" (a plate of 

 granules) may sometimes (thoug apparently not always) be formed. 



The fact that in Euchistus the second reduction division may be, 

 as a variation, transverse instead of longitudinal, is especially inter- 

 esting as being a point in corroboration of the conclusion of O. Hert- 

 wig, in opposition to Weis mann, that in reduction it is the halving 

 of the chromatin mass and not the plane of division which is the im- 

 portant result. And in the same cell some of the chromosomes may be 

 split longitudinally, some transversely. 



3. Unbefruchtete Eier von Ascaris megalocephala. 



Von M. Nussbaum, Bonn. 



eingeg. 2. Januar 1899. 



In der Sitzung der Berliner Akademie vom 3. Nov. 1898 hat auch 

 O. Hertwig diesen Gegenstand behandelt. Beim Lesen des Berichtes 



