Cytology and Movements of the CyanophycecB. 245 



cause the filamentous plants to assume the forms of short 

 rods and coccus-shaped cells, thus proving that a much 

 closer connection existed between the Cyanophycese and the 

 Bacteria than had been hitherto supposed, even by Cohn or 

 Sachs (66) who were the first to place the two groups 

 together in the Schizophyta. Several forms as here 

 described are doubtless produced when a filamentous alga 

 breaks down in death, but it would, however, scarcely seem 

 proper to consider as a part of the life-history of a plant, a 

 phenomenon caused by an evident pathological condition. 

 Methods quite similar to those used by Zopf were employed 

 in the present investigation for the purpose of causing spore 

 formation, with the result that the filaments would break 

 down after forming spores. These may be the unicellular 

 forms spoken of by Zopf. Concerning the structure of the 

 cell, he says little, except to assert that a nucleus was present 

 (96) in Pliragmonema, but he was somewhat uncertain as 

 to whether it should not rather be termed a vacuole. 



According to Gomont (33) the cells and hormogonia of 

 the Homocystese always possessed a delicate laminated mem- 

 brane, which in the later formed and younger cells consisted 

 of a substance closely allied to cellulose, but in the older 

 cells it resisted all such reagents and he considered it to be 

 a substance between the cuticle of the higher plants and 

 fungus cellulose. The sheath of the Homocyste?e (31) 

 ranged between hyaline and gelatinous, becoming hyaline 

 for protection when exposed to light and air. It was dis- 

 tinctly laminated. The protoplasm was colored uniformly 

 a blue-green, but had small granules of two kinds, one 

 small, irregular in outline, refringent and collected usually 

 at the ends of the cells, the other about \ ft to 2 fi 

 in diameter and supposed by Zacharias (89) to be composed 

 of a hydrocarbon. The former were most abundant in the 

 older cells, being scarcely shown in the growing tip where 

 division is most abundant, and were entirely lacking in 

 newly formed cells. Both kinds of granules could exist in 



