228 BOTANICAL GAZETTE [SEPTEMBER 
THE FORMATION of the heterotypic chromosome is described in a recent 
article by Brrcus.** Although referring often to a “longitudinal division” 
of the spirem, the writer wishes it understood that he means merely the appeat 
ance throughout the length of the spirem of two filaments more or less paral, 
Whether the two filaments result from the splitting of a single filament or whether 
there is simply the reappearance of two distinct filaments will be discussed ina 
future paper. The split which appears in the spirem is the one which separates 
the two filaments entangled in the strepsinema stage. The spirem passes ino 
the strepsinema stage by a longitudinal fission, not by looping and approximation, 
as Dixon claims. After the strepsinema stage, the chromosomes are (i 
pleted by a thickening and shortening. The two pieces, which the heterotypic 
mitosis separates, are the two longitudinal pieces of the spirem thread. If there 
is an approximation, it must be looked for during the formation of the spirem 
This latter point will be discussed in a forthcoming paper.—CHARLES J. CHa 
BERLAIN. 
ROSENBERG,’S in continuing his studies upon Drosera rotundifolia, describes 
the two mitoses in the pollen mother-cells and arrives at some interesting conclt: : 
sions. In an early prophase of the first division, before the disappearance 0 | 
the nuclear membrane, the chromosomes appear in pairs, which soon unite 
form double chromosomes. There are 20 such double chromosomes, “2 
are formed by the uniting of the 40 chromosomes of the vegetative mitoss ®© 
a series of diagrams the paternal and maternal chromosomes are ie 
first as distinct, and soon after as approximated in pairs. Each paternal 
maternal chromosome now divides, and all of the paternal chromosomes P&S 
to one pole and all of the maternal to the other pole. The second ral 
simply separates the two parts of each chromosome, which was already j 
during the prophase of the first division, so that in two of the four pollen er 
all of the chromosomes are paternal and in the other two, all at ‘oso 
Suggestion is made that the double thread of the early spirem 1s as ae 
rather than to splitting, and is consequently a process of reduction. 
J. CHAMBERLAIN. 
Two papers from the University of St. Petersburg bear upo? 
enzymes in respiration. Both are based upon quantitative work. ie ie 
KostytscHEew?? experimented with Mucor stolonijer and Asper 
the rile of 
*4 BERGHS, JULES, La formation des chromosomes heterotypiques per 7 
Some végétale. I. Depuis le spir’me jusqu’aux chromosomes ee ). Le ad 
Sporogénése d’ Allium fistulosum et de Lilium lancifolium (spe ee 
21: 173-189. fig. 15. 1904. Meddel. Sod 
*5 ROSENBERG, O., Ueber die Reduktionsteilung im knee but the via 
holms Hogs. Bot. Inst. pp. 13. figs. 20. (Reprint signed — ge ted. 
and date of the publication in which the article appeared are not er 
26 Kostytscuew, S., Uber Atmungsenzyme der Schimmelpilze- ie 
Bot. Gesells. 22:207-215. 1904. | 
