Cytology and Movements of the Cyanophycee. 317 
on the different sides.’ In order to account for the rapidity 
of this motion being greater than could possibly be caused 
by the one-sided splitting of the cells of the trichome, Stras- 
burger continued, “These flexions usually take place slowly, 
but can, however, induce violent movements when the flex- 
ion is stopped by some obstacle, and then by overcoming 
this the tension is suddenly equalized. The movements can 
only take place when the threads have a point of support on 
some other object.” This last statement is contrary to the 
observations of Engelmann, as well as my own, as will be 
shown later. The evidence of nearly all observers on the 
hormogonia would also militate against it. 
The observations of Schultz and his followers seem much 
more to the point. Such movements occur nowhere else 
among living organisms without the presence of some kind 
of locomotory apparatus, usually cilia in some form. In 
the light of the facts above stated, it would seem, therefore, 
that we have only two methods left as plausible explana- 
tions of the motions of the Cyanophycez, 1. e., either (a) a 
protoplasmic pellicle which creeps along on a substratum 
- and which acts in a peristaltic manner, or (b) the plant has 
some propelling organ as flagella or cilia or pseudopodia, 
that act either upon the solid substratum or that move freely 
through the water. The former of these theories could 
scarcely account for all of the activities, though it might 
assist in them. While studying the species of Oscillaria, I 
was convinced that there was, at times, a very delicate pel- 
licle surrounding the trichomes. This pellicle, as is shown 
above, would take a delicate tint with protoplasmic stains. 
On several occasions I saw a lengthening and shortening 
of the cells as in peristaltic movement, but it was by no 
means sufficient to cause the oscillation and especially the 
creeping movements of the organism. Neither was there 
any observed evidence that the peristaltic movements, if 
such they could be called, were caused by the surrounding 
delicately staining sheath, even though it should prove to 
