Cytology and Movements of the Cyanophycece. 271 



loids are usually crowded into the heterocysts, being at the 

 ends where the pore enters, or in the spores, or in the older 

 vegetative cells that have ceased to divide. They are entirely 

 absent from the young, rapidly dividing cells. Their crystal- 

 loid character is attested by their sharp angular outlines. 

 Their albuminous character is shown by their chemical and 

 staining properties. (11) In cultures grown in the dark, 

 these albuminous crystalloids are consumed. They are also 

 consumed in the germination of spores. Such facts, together 

 with their always being formed where food material is 

 accumulating caused Hegler to regard them as reserve ma- 

 terials. (12) The slime vacuoles are difficult to distinguish 

 from the albuminous crystalloids except by staining reac- 

 tions, and their composition cannot be exactly identified. 

 Their staining properties, however, caused Hegler to con- 

 sider them to be a slime material, very much like albumen, 

 similar to that present in Fucus vesiculosus, and many other 

 plants. It approaches nearest to mucin. (13) The chemical 

 and physical properties of the granular parts enclosed in the 

 peripheral protoplasm, together with their incapacity to 

 increase by division, and their entire absence in the dividing 

 cells indicate that neither of these granules can be consid- 

 ered as of a nuclear nature. (14) The principal point in 

 the question of the Cyanophycean cell was that of the nature 

 and importance of the so-called central colorless body. 

 Hegler considered that his investigations had conclusively 

 proven that these central bodies were the cell nuclei of the 

 Cyanophycese, and that their behavior during division gave 

 sufficient grounds on which to base this judgment. (15) 

 In all cells of the Cyanophycese with the exception of the 

 heterocysts where the nucleus early degenerated, there was 

 a single cell nucleus whose form depended to a great degree 

 on the size of the cell. In round cells it was spherical, in 

 elongated cells elongated, the long diameters of the cell 

 and nucleus being parallel. (16) The resting nucleus con- 

 sisted of a slightly stainable foundation mass, in which were 



