328 BOTANICAL GAZETTE [OCTOBER 
investigators indicates that these are the bodies heretofore desig- 
nated as chromosomes. 
This spireme in the pachyneme stage is composed of deeply 
stained short filaments intermixed with material of a granular 
nature. There is evidence that this granular material was derived 
from the nucleolus, the filamentous from the nuclear network. 
These two materials amalgamate to form one of intensive stain- 
ing capacity. The amalgamated material retains the spireme form. 
This spireme as a whole is spherical, later elongates, becoming 
cylindrical. Cross-sections of the loops reveal their tubular struc- 
ture. 
This spireme does not appear to split either transversely or 
longitudinally, but separates at various points as would a viscid 
mass if pulled in opposite directions. Fourteen or more tubular 
chromosomes for each daughter nucleus result from the elongation 
of the coils of the spireme. These are not to be considered 
“pseudochromosomes.”’ 
At this stage and subsequently chromidia are discharged into 
the cytoplasm. It is probable that these chromidia are concerned 
in the development of pyrenoids. 
There is no evidence throughout the karyokinesis of an equa- 
tional division of autonomous bodies. The advantage of this form 
of division over direct divisions appears to lie in the opportunity for 
escape of the chromidia from the nucleus. : 
Spirogyra crassa does not in the behavior of its nucleus in 
karyokinesis present a unique case, for the stages can be homolo- 
gized with similar stages in Allium, as typical of the higher plants. 
NorMat CoLLece 
New York Ciry 
LITERATURE CITED 
1. Bercus, J., Le noyau et la cinése chez le Spirogyra. La Cellule 23:55-86- 
pls. 1-3. 1906. 
2. Bonnevir, K., Chromosomenstudien I. Archiv. Zellforschung 11450 
515- 1908. Chromosomenstudien II. Ibid., 2: 201-278. 1909. 
3. Bouster, A.M., Contributions a étude du pyrénoide. Bull. Herb. 
BorssteR 72451-458, 554-559. 1890. 
