Cytology and Movements of the CyanophycecB. 287 



it would not fall far short of the restricted conception of a 

 nucleus. It has a much more definite form than the diffused 

 nucleus of the Infusorian Trachelocerca, as described by 

 Gruber (29), and the ground substance of the central body 

 quite represents the more fluid parts of the nucleus, while 

 Hieronymus, Strasburger and others have been able to find 

 a definite nuclear membrane. The second, and more com- 

 prehensive definition of a nucleus, is certainly fulfilled by 

 the central body of the Cyanophyceae. There is as much 

 evidence for the chromatin of the Cyanophycese being the 

 hereditary material of these organisms, as there is to con- 

 sider it such in the higher plants. Moreover, that the con- 

 structive metabolism is governed by the central body is 

 evidenced by the fact that plants which have been cultivated 

 in solutions which starve the chromatin, are never healthy 

 and strong, the cyanophycin grains often disappearing. The 

 definite threads of kinoplasm which radiate from the central 

 body and pass into the ciliary processes, suggest evidence 

 that the movements are directed by the same organ, while its 

 activities in the formation of spores and in division show 

 that it has much to do with reproduction. The argument 

 that the central body has no stable morphology has been 

 refuted by Biitschli (9), who showed that it is no more 

 variable than true nuclei. Strasburger also mentions the 

 finding of cells, no longer capable of division, which might 

 have several nuclei, the result of fragmentation. The cen- 

 tral body of the bacteria was studied by Nadson, who con- 

 cluded that their nucleus was diffused throughout the whole 

 of the cytoplasm, very much as the present investigation has 

 shown the coloring matter of the Cyanophycese to be. This 

 would mean the same intermingling of the functions of 

 cytoplasm and nucleus as exists between the functions of 

 cytoplasm and chromatophore in the Cyanophycese. This 

 form of protoplast Nadson termed an "Archiplast." He 

 often found scattered granules of chromatin in the Archi- 

 plast. Biitschli considered the bacteria to consist of a cen- 



