700 THE AMERICAN. NATURALIST. (VoL. XXXIX. 
We may pass now to the peripheral region of the cell which 
holds the blue-green coloring matter of the Cyanophycee. A 
number of investigators, as Wager (:03), Kohl (:03), Hegler 
(:or), and Hieronymus ('92), have held that this pigment was 
contained in minute granules distributed throughout the cyto- 
plasm under the cell wall. These granules have at times been 
termed chromatophores or plastids and Hegler has proposed for 
them the name cyanoplastids. Other authors, especially Fischer 
(97), Nadson ('95), Palla (93), and Zukal ('92) have been unable 
to find these color-bearing granules and have believed the color- 
ing matter to be uniformly diffused throughout the peripheral 
region of the cell. Fischer has made a particularly thorough 
study of the reactions of the pigmented region to various acids 
in comparison with the chromatophores of higher alge and con- 
cludes that no plastids are present but that the color is held in a 
hollow cylindrical or spherical outer layer of protoplasm which 
may be termed a chromatophore. Olive supports Fischer, 
approaching the subject from a very different point of view. If 
minute plastids are present they should be visible in fixed and 
stained material and Olive is unable to find any trace of Hegler's 
cyanoplasts. The granules of the outer region of the protoplast 
seem to be colorless inclusions. 
Perhaps the most confused part of the discussion on the 
structure of the cell of the blue-green algze is that which deals 
with certain inclusions. There are apparently two sorts which 
are very common in the cells: (1) the cyanophycin granules 
(Borzi) and (2) the slime globules. The cyanophycin granules 
are very apt to lie along the cross walls in filamentous forms or 
in other peripheral regions of the cell. They are generally 
believed to be a form of food material and it has been suggested 
that they are the first visible product of photosynthetic processes, 
but their chemical nature is under dispute. The slime globules 
lie more frequently in the interior region of the cell close to the 
nucleus and frequently within this structure. They have been 
termed nucleoli by some authors and also confused with chro- 
matin. Besides these two bodies, other minute globules have 
been described as oil or fat and some remarkable crystalloid 
structures have been figured, especially by Hieronymus ('92). 
