356 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
I find little evidence of a chromonema in the telophase of the spermogonial divisions 
and what evidence there is would indicate that the chromatin becomes distributed on the 
inner surface of the vesicular walls, not on the outer surface of an achromatic core. 
There is an implication here that the chromosome is hollow in some¬ 
what the same sense as I have described it. 
According to Suessenguth (1921), who worked on Rhoeo, one of the 
Commelinaceae, the chromosome has a moniliform structure made up of 
ten segments. Each of the latter, I take it, would be homologous to the 
chromomere as defined by Eisen. Eisen considered that the chromomere 
is made up of six chromioles, but that the number of chromomeres in a 
chromosome may be variable. 
In conclusion, it seems to me, both from my own work and from the 
evidence in the literature, that the distinction between chromatin and 
linin is universally valid, and that, when preparations do not show this 
distinction, as in those of Gregoire and Wygaerts (1903) and of Sharp 
(1913, 1920) for the telophases, where, according to them, the chromosomes 
break up by vacuolation, it is due either to overstaining or to shrinkage. 
The linin of the chromosome is distinctly a more or less regular cylinder 
of jelly-like consistency in which the chromatin is imbedded. It is not 
provided with an outer membrane which could be demonstrated by any 
of the methods used. 
The chromatin is grouped into bodies, the generally recognized chromo¬ 
meres. In Tradescantia these are of variable shapes and sizes, and, as 
far as present evidence goes, their number in the chromosome seems variable. 
The colloidal structure of the chromosome is conceived to be primarily 
a two-phase system with the chromatin representing the disperse phase 
and the linin, the continuous phase. The continuous phase, within the 
body of the chromomere, may be more dehydrated than that present in the 
linin proper. That there may be still further phases of colloidal dispersion 
within the chromomere is not denied. At any particular stage of mitosis, 
an individual chromomere may have a greater or a lesser degree of dehydra¬ 
tion than its neighbors in the same or in other chromosomes. This degree 
of dehydration may represent a specific constant for each chromomere for 
any particular stage. Since the coefficient of dehydration between the 
chromomeres may be a variable, only identical phases would be comparable, 
and it might be expected that in the end result of fixation, imbedding, and 
staining, the relative proportional dehydration values would be maintained. 
The writer is indebted to Professor R. A. Harper and to Professor 
C. C. Curtis for many helpful suggestions during the course of this work. 
LITERATURE CITED 
Allen, C. E. 1905. Nuclear division in the pollen mother-cells of Lilium canadense. 
Annals Bot. 19: 189-258. Pis. VI-IX. 
Alverdes, F. 1912. Die Kerne in den Speicheldriisen der Chironomus-Larve. Arch. 
Zellforsch. 9: 168-204. Pis. XV, XVI. 
