750 THOS. H. MONTGOMERY, JR. 
D. There is no continuous chromatin spirem produced in the 
prophases, but the univalent chromosomes conjugate to form 
pairs or gemini and these undergo a reductional and an equa- ~ 
tional division. This view, now shared by the great majority of 
students, exhibits itself under these aspects: 
D. 1. The chromosomes conjugate metasyndetically. 
(a.) Thereduction in numbe of the chromosomes is effected 
by the first maturation mitosis (Montgomery, ’00; Farmer and 
Moore, ’03). 
(b.) The reduction in number of the chromosomes is effected 
by the second maturation mitosis, McClung, ’00, and his students. 
D. 2. The chromosomes conjugate parasyndetically, and the 
first maturation mitosis is reductional; Winiwarter (’00), Grégoire 
(04), Berghs (’04), A. and K. E. Schreiner (04, ’05). 
We may now discuss the relative validity of these different 
views, referring the reader for a full bibliographical treatment to 
the review by Grégoire. 
Interpretation I is founded to great extent upon negative | 
results, and rather ignores the numerous cases where particular 
forms and sizes of chromosomes can be followed through different 
generations with a high degree of certainty. It also denies the 
persisting continuity of chromosomes, an attitude based entirely 
upon, negative evidence; it argues that at certain times one can- 
not see the boundaries of chromosomes, therefore they must have 
lost their individuality. This view further gives no satisfactory 
explanation of why the chromosomes of the first maturation 
mitosis are so different in form from other chromosomes. 
Interpretation II meets the great consensus of modern opinion, 
and I believe it to be fu'ly established. On the four principal 
variants of this view the following criticisms may be passed: 
The view IIA meets no modern confirmation of any description, 
it being well established that not more than one maturation 
division is reductional. 
The view IIB was based on Henking’s observations on Pyrrho- 
coris, but all later students of hemipteran spermatogenesis have 
shown that gemini are produced before the maturation mitoses; 
