Igor] EREMOSPHAERA AND EXCENTROSPHAERA 313 
was not visible in my material, neither was the platelike expan- 
sion which he says is drawn out from the middle of the chro- 
matophore and may consist of two or three bent wings, causing an 
irregularly shaped dark spot in its center. A good sized pyrenoid 
is always distinctly visible, there being sometimes as many as 
three or four in each chromatophore. If the chromatophore be 
treated after the manner of Mayer, first adding a dilute iodine 
solution and then chloral hydrate, the crystalline structure of the 
pyrenoid is easily seen (fg. z8), and the layer of starch sur- 
rounding it made visible. 
The wall of Eremosphaera is normally thin and of but a 
single layer in thickness, but it has the property of great gela- 
tinization, and is often laid down in successive layers. This 
condition gives rise to the forms characterized by Chodat as the 
Gloeocystis, Palmella, and Schizochlamys stages. The duplica- 
tion of the wall does not seem to be confined to particular periods 
of development, but may occur at any time. Each wall soon 
becomes separate and distinct from the adjoining ones, and with 
care the several coats may be broken one at a time and the con- 
tents allowed to slip out. That such forms are really what 
botanists recognize as Gloeocystis or Schizochlamys is doubtful. 
While it is possible that Emerosphaera, surrounded by a number 
of gelatinous walls, might be mistaken by a hasty observer for a 
similar condition in either Gloeocystis or Schizochlamys, it does 
not necessarily follow that these genera are one and the same 
thing. Schizochlamys, I have been able to cultivate for a con- 
siderable length of time, and it has never exhibited any evidence 
of being related to Eremosphaera. Since we can have the same 
duplication of the wall in Chlamydomonas and other genera 
widely separated from the ones under discussion, it hardly seems 
a sufficient basis upon which to unite a number of forms frequently 
showing marked differences in their life histories. 
In addition to the successive formation of coats around 
Eremosphaera, there sometimes occur peculiar growths on the 
inner surface of the wall, which are the result of a number of 
layers of cellulose being formed about a central point (jig. It). 
a iS c 
