1898-99. | ON THE CYTOLOGY OF NON-NUCLEATED ORGANISMS, 473 
present and these are found in the peripheral layer. The substance 
which forms these stains deeply with picrocarmine and with difficulty 
with hematoxylin. It appears to contain “ masked” iron. 
8. The heterocyst is a degenerated cell in which all distinction between 
the central and peripheral parts is lost. The chromatin-like substance 
of the central body diffuses throughont the cytoplasm when the hetero- 
cyst is forming. When fully developed the cytoplasm gives a feeble 
reaction for iron. A small mass at one or either pole of the cell gives a 
distinct reaction for “masked” iron and stains deeply with picrocarmine. 
Further, as it does not dissolve in acids, it is not related to the substance 
which forms the granules of the second type. 
g. There is no nucleus, nor any structure which resembles a nucleus, in 
the Cyanophycee. 
10. Division of the cell is direct, the central body first showing the 
effects of this process. When a large spherule of chromatin-like sub- 
stance is present it may pass into a daughter cell, or it may be 
mechanically divided between the two daughter cells. 
