286 Prof. H. Karsten on the Formation, 
of filaments the other cells of which exhibited the normal annular 
folds; and I only noticed it with clearness after the action of 
solution of iodine and chloride of zinc upon the plant had tinted 
the deeply penetrating fold of the cell of a dark blue colour, 
By this means it was seen to extend very gradually and to out- 
stretch itself, until it had fully emerged from the membranous 
sheath and became no longer distinguishable from a cell which 
had suddenly extended itself in the usual manner. The secondary 
cell was contracted around its contents, as is exhibited in PI. VII. 
fig. 49; but sometimes also the chlorophyll and amylaceous 
contents expanded themselves and filled the whole of the lower 
space of the cell as far as the margin of the enveloping sheath. 
This phenomenon I once observed taking place in several in- 
dividuals of Gfdogonium grande with great uniformity, and, as the 
evolution took place very slowly, with great certainty ; but simce 
then I have looked for similar examples in vain, and can there- 
fore, much to my regret, contribute nothing further respecting 
the conditions under which this interesting act of fold-construc- 
tion takes place. 
Nevertheless it furnishes a fresh proof against the view spoken 
of—namely, that the cellulose membrane is the external thicken- 
ing layer (or, as Mohl’s school would represent it, excretory 
layer) of the secondary cell,—and can only be explained by the 
developmental faculty of the independently assimilating cell-wall. 
Moreover the opinion that the normal annular fold is simply 
an excretion from the primordial sac is completely hypothetical. 
There is nothing to show that the secondary cell possesses in 
the portion contiguous to the rg any other or stronger powers 
of vegetation than in any other portions. 
Besides the well-known and frequently described development 
of spores and gonidia, I also observed other organs, the func- 
tions of which are still unknown to me, but which, on account of 
their aberrant and strange developmental phenomena, certainly 
merit more general attention ; for which reason I do not think 
I shall be accused of precipitancy for publishing here the little 
that I have observed respecting them. 
Bary indeed appears to have met with something similar; 
for he has described and figured (Senckenberg Transactions, 
vol, i.) certain “globules of decomposition” (Zersetzungskugeln), — 
which were produced from the joint-cells of dying specimens of 
Cdogonium capillare, CL. acrosporum, and Ci. echinospermum. 
Bary saw the aggregated mass of contents form into a globule, 
—_— 
and escape from longitudinal rents in a cell, commencing in the — 
still unthickened and soft membrane of the recently extended — 
annular fold. He more rarely noticed them escapmg through — 
the old and firm cell-membrane. 
hoy 
