Cytology and Movements of the Cyanophycee. 313 
demonstrate the position of the flagella described by him. 
The probability is that he referred to the long hair-like 
projections from the end cells, which have been described 
by Borzi and Hansgirg as parasitic organisms, and to which 
he here gave the functions of definite plant organs. He also 
intimated that pseudopodia about 0.03 mm. in length 
passed through the cell wall. The only figure in all of the 
literature reviewed which shows any such organs, other than 
these so-called parasitic growths, accompanies Zukal’s paper 
(101) where he figures several long whip-like flagella 
springing from the division walls of Cylindrospermum stag- 
nale, though no mention of them is made in the paper. (See 
Fig. 65, which is copied from Zukal’s drawing.) 
Hogg (42) found cilia on the ends of diatoms and in 
isolated positions along the sides, but his views have received 
no support from other investigators, and it is likely that he 
misinterpreted effects of lighting, as was pointed out by 
Wenham (82), who considered motion to be due to a pro- 
toplasmic layer surrounding the frustule. 
Wolle’s views (87) were expressed by him as follows: 
“By the careful observation of living plants the process of 
cell multiplication can be readily detected in the larger 
forms. Ordinarily the split of a cell commences on one 
side and then continues from the opposite side; a number of 
cells dividing at the same time will have the tendency to 
throw the end of the filament out of line, first on one side 
and then on the other, thus producing a vibratile motion. 
The process of creeping may be conceived in connection 
with growth, and yet it may not satisfactorily explain every 
movement. The apparent correspondence between the 
rapidity of growth and that of the creeping filaments is not 
without significance. The larger forms of Oscillaria are 
found to grow by cultivation at the rate of about one-half 
inch in an hour. The creeping of the same filaments pro- 
gresses at the same rate, age of the filaments and other 
circumstances corresponding; hence the reasonable infer- 
