Cytology and Movements of the Cyanophycee. 239 
port living organisms. No other class of plants can exist 
under such varied surroundings, though each species is most 
delicate in its response to its own environment. In the hot 
springs of the Yellowstone National Park, where the water 
reaches 190° F., the boiling point at that altitude, these are 
the only organisms that can find the necessary conditions of 
existence. They range from such conditions through all 
temperatures to the frozen seas of the North, and though 
the waters be strongly impregnated by alkaline salts or acids, 
the organisms are not yet excluded. It is just such environ- 
ments that one would expect to find in the beginning of the 
earth’s phytological history, and it seems reasonable to con- 
sider these organisms as the surviving basis of a phytolog- 
ical tree. Their power of elaborating food in the dark as 
claimed for the Cyanophycee by Hansgirg, and their abil- 
ity to withstand long periods of drying which will shrink 
their cells to one-third of their natural size while still retain- 
ing their vitality, would also be in favor of their primitive 
origin. 
There are many cytological problems locked up within 
the cells of the Cyanophycez, but in the past investigators 
have mostly confined themselves to the questions of the pres- 
ence of nuclei and chromatophores. These still constitute 
the fundamental questions which must be confronted. Palla 
(60) thus sums up the situation in this respect: “We have 
three possibilities before us, either (a) the Cyanophycean 
protoplasts have true cell nuclei, whose significance we have 
not known up to the present time, or (b) the nuclei of the 
progenitors of the Cyanophycee have been reduced until 
they have entirely disappeared, or (c) the Cyanophyceze 
are without nuclei.” Though the present investigation does 
not confine itself to the nuclear side of the problems, never- 
theless this phase of the subject must necessarily receive 
much attention. It was therefore with much interest that 
the subject in hand was entered upon at the suggestion of 
Professor Macfarlane, who has watched the different steps 
