Cytology and Movements of the Cyanophycece. 269 



mitotic division was merely made up of aggregated crystal- 

 loids. Division was accomplished by an ingrowth of the wall, 

 which cut the chromatophore and then the central body, but 

 the central body itself did not, pari passu, begin to divide as 

 in direct division of the higher plant nucleus. It was merely 

 constricted by the ingrowing peripheral wall until a slight 

 tag of protoplasm remained to connect the halves. This 

 finally separated and division was complete. The central 

 body was vacuolated and the pressure of these vacuoles 

 caused the granules of the central body to become heaped 

 up. Concerning the bacteria, Fischer considered the claim 

 that they absorbed nuclear stains to be a myth. The cen- 

 tral body described by Butschli as having clear ends he con- 

 sidered to be nothing more than the plasmolized protoplast. 

 He found in these organisms, within the cell wall, first a 

 protoplasmic wall-facing that surrounded a sap vacuole. A 

 nucleus was not to be seen, the colored granules being 

 reserve food material within the cell. The relation of the 

 sulphur and other bacteria to the Cyanophyceas was very 

 loose and mostly morphological. 



Probably the most exhaustive work that has yet appeared, 

 and certainly the one which commanded greatest interest 

 on account of the advanced ground taken was by Robert 

 Hegler (38). The conclusions drawn in this article were 

 so far-reaching, and in many respects so exhaustive, that it 

 seems best to give his results at some length, substantially 

 as summed up by himself in his concluding remarks, though 

 adding some points to make them more clearly understood, 

 (i) The cells of the Cyanophyceje are in all cases sur- 

 rounded by a cell membrane of peculiar material, distinct 

 from the sheath, which latter is identical with the capsule of 

 the encapsulated bacteria. Naked cells do not appear in 

 these plants. The hormogonia do not possess a demon- 

 strable membrane. (2) The gelatin coverings and the 

 sheaths are the products of the membranous walls. The 

 sheaths as well as cell membranes have a marked power of 



