SPERMATOGENESIS OF EUSCHISTUS 751 
and based also upon Korschelt’s account of Ophryotrocha, but 
this has been controverted by the accounts of Grégoire and Deton 
(06) and of the Schreiners (06b). Therefore this view has no 
longer any support. ; 
View IIC is a much closer approximation to the truth, because 
it grants that gemini are produced during the growth period. 
The objection to it is that there is probably no continuous chro- 
matin spirem produced in the prophases of the first maturation 
division nor in any portion of the growth period; this objection 
was first urged by me (’00) as one of the many differences between 
spermatogonia (or oogonia) and spermatocytes (or oocytes), 
receives strong confirmation in my present observations, and has 
been sustained by Grégoire and numerous other investigators; 
only Meves and his school still oppose our contention. It is 
not a minor but a major difference, for the segmentation of a 
chromatin spirem is one thing, the conjugation of univalent 
chromosomes into gemini quite another matter. The conclusion 
that like or homologous chromosomes pair together to make 
gemini is the only conclusion that suffices to explain why, in the 
spermatid or the ootid, ail the chromosomes may be unlike in 
form or size. 
Therefore we must subscribe to the view IID, that there is 
no continuous chromatin spirem produced, but that the gemini 
are engendered by the pairwise conjugation of univalents and that 
they undergo one reduction division. This idea of a true conju- 
gation of chromosomes was brought out by von Winiwarter and 
myself independently in 1900, and in the following year I showed 
that this is a conjugation of correspondent maternal and paternal 
chromosomes, therefore really the final step in the fertilization 
process of the germ cells. This view IID has been substantiated, 
if the greater consensus of modern opinion may be taken as a 
test of truth. 
Twelve years ago, when I wrote my first paper on Euschistus 
(Pentatoma), those who held to the occurrence of a reduction 
division, and they were but few—Riickert, Vom Rath, Hicker, 
Wilcox, and in opposition to the authoritative opinions of 
