Cytology and Movements of the Cyanophycee. 323 
Fischer (28) found membranous projections passing 
from around the central body into the surrounding chroma- 
tophore. He considered them to be continuous with the 
protoplasmic membrane around the chromatophore (Figs. 
29 and 32 are copies of his drawings). These membranous 
projections, I think, are evidently the prolongations of the 
ground mass from the central body or nucleus, to the cilia, 
though he failed to see them pass the cell wall (compare 
Figs. 29 and 32 with Figs. 31 and 38). I have, with 
Engelmann, been able to see Oscillaria and Cylindrosper- 
mum swimming freely in the water, which is beyond the 
power of pseudopodia to cause. It is therefore evident that 
the creeping movements of these organisms are effected by 
the action of definite, very delicate, short cilia. These were 
demonstrated around the wall of the cells in a more or less 
uniform number (compare the various figures). 
The contention of former writers that motion in the 
Cyanophycez was caused by light, heat, etc., does not in any 
way militate against the views here taken. The effects of 
these stimuli are but the workings of the ordinary laws of 
biology. Wigand (84) showed that light was a prime fac- 
tor in the protoplasmic movements of the higher plants, and 
in the Cyanophyceze we find the same thing to be true. 
Movement is much stronger in the light than in darkness, 
and it is probable that if they could be observed in total 
darkness, there would be no motion at all. The action of 
heat and cold was also the same in these organisms as in the 
higher cells. By means of Reichert’s warm stage, I observed 
these organisms under varying conditions of temperature 
and found that they had their maximum, optimum and 
minimum temperatures, just as found in other plant cells. 
(8) CoNcCLUSIONS. 
The line of demarcation between the Cyanophyceze and 
the other alge has been based upon the threefold negative 
