Olive, Mitotic division of tlie nuclei of the Cyanopliyceae. 
33 
tlie arrangement in tlie elongating cell of the chromatin gra- 
nules in a spireme threach In the opinion of the writer, there- 
fore, the nearest approacli to a resting state of the nucleus, 
under tlie usual conditions, at least, is probably best illustrated 
by figs. 62 and 64, in which the daughter chromosomes remain 
separate and distinct, and surronnded by achromatin, until rear- 
ranged in a spireme for the next division. A breaking np into 
smaller grannles of chromatin and the formation of a reticulum 
such as is characteristic of the nuclei of higher organisms is 
not evident; and no nuclear sap is secreted, consecpiently there 
is 110 limiting membrane. It is possible, however, that fig. 16 
illustrates a nearer approach than is usual to a normal resting 
condition; and that hg. 33 shows the beginnings of the form¬ 
ation of karyolymph (or the spaces may be occupied by slime 
globules?); and further, that in certain cells of figs. 6 and 14, 
the nuclei have entered partially into a state of rest. 
Cell inclusions. 
In tlie foregoing pages, mention has been often made of 
cyanophycin grannles (a name given by Borzi) and shme glob¬ 
ales (Palla), or „Zentralkörner u (Zacharias) which occur so 
abundantly in the cells of the Cyanopliyceae. It is highly pro¬ 
bable, in fact, that the cyanophycin grannles are a type of reserve 
food material peculiar to tliese plants; while the slime globules 
have a much wider distribution, having been found by Biitschli 
in Diatoms, Flagellatei, in tlie epidermal cells of Phanero- 
gams, etc. 
Minute plastids — the „Cyanoplasts“, as called by He gl er 
— are said by several investigators to be present and to contain 
the green and blue coloring matters. The writer agrees witli 
Fischer, however, that the coloring matters are held, not in 
plastids, but diffused in a peripheral chromatophore. He gier, 
in his article, added another substanee -— glycogen — to our 
list of the cell inclusions of the Cyanopliyceae ; and Kohl (03) 
confirmed his discovery, giving a list of twelve genera in which 
glycogen occurs. It is the opinion of both He gl er and Kohl 
that this substanee is the first perceptible product of assimilation 
in the blue green algae. I have not yet been able, however, 
after many careful tests made both with sections as well as with 
fresh filaments, successfully to demonstrate glycogen in Oscilla- 
toria. Equally unsuccessful have been many tests with sudan 
and otlier reagents, made also with Oscillatoria , for the purpose 
of determining the presence of tlie minute fatty oil globules, 
said by Zacharias and Kohl to occur in the cytoplasm of 
Tolypotlirix. 
It is not the purpose of this paper to discuss the compo- 
sition or tlie probable function of the two kinds of granulär 
inclusions of the cytoplasm which have been found by the writer 
in all the forms studied, since tlie microchemical tests which I 
have so far made will not warrant definite conclusions. Attention 
Beihefte Bot. Centralbl. Bd. XVIII. Abt. I.'Heft 1. 
3 
