Cytology and Movements of the Cyanophycecs. 319 



tention that they arise from amoeboid bodies in a broken 

 cell is not to the point, because they often arise in unbroken 

 end cells. Further, Hansgirg considered that the long hair- 

 like appendages along the sides of Cylindrospermum were of 

 the same nature as the hair-like organs of Oscillaria. But 

 since these long processes only appear upon the sides of the 

 heterocyst and spores, both of which have strongly thick- 

 ened walls, it can scarcely be thought that any parasitic 

 organism would penetrate these, and not be found upon the 

 thinner-walled vegetative cells. I therefore placed some of 

 these filaments in a live-box and kept them under continuous 

 observation until these hair-like organs were completely 

 formed, which usually consumed from one to three hours, 

 according to the strength of the culture and other condi- 

 tions involved. Observation was continued for several days, 

 and I was rewarded many times by being able to trace the 

 gradual development of these so-called parasitic growths 

 from the protoplasm of the end cells, noting them in all 

 stages of their growth from small swellings to the full- 

 grown hairs. When a trichome is broken across, the final 

 cell of each broken end exhibits the normal structure (Fig. 

 39). Gradually the chromatin of the central body becomes 

 diffused and the free end bulges out, on account of the tur- 

 gor and relieved pressure from the other cells, on one side 

 (Fig. 33). As this proceeds, small finger-like processes 

 begin to appear as small swellings over the free surface of 

 the cell. These gradually grow out until they become eigh- 

 teen or twenty times as long as broad. In their younger 

 condition, they take the stains in the same manner as the 

 protoplasm of the end cell, but gradually they become more 

 impervious to these stains and react in the same manner as 

 the cell walls, except for the thin protoplasmic continuation 

 into their lumen. Thus it will be seen that they slowly 

 harden into a cell wall by the deposition of some substance 

 which no longer takes the stain as the softer protoplasm 

 does. They gradually assume the reaction of cellulose. 



