332 Cleland . — The Cytology and Life-history of 
however, to be no resemblance between the methods of action of the 
pyrenoid of Hydrodictyon and Anthoceros, and that o.f Nemalion . What- 
ever may be true with reference to the action of the central body in 
Nemalion , this much is certain, there is no segmentation or cleavage of the 
body to form starch grains. Having once attained its mature state it 
remains constant in size and appearance and never gives rise to any bodies. 
In other words, as Schmitz stated, it takes no actual morphological part in 
the process of starch formation. The fact, however, that we do not have in 
Nemalion a pyrenoid of the nature described by Timberlake and McAllister 
does not mean that it takes no part in photosynthesis. Starch grains are 
never formed in this plant through any agency, although reserve food is 
actively elaborated. 
I have made some tests, both on living and fixed material, for the 
purpose of ascertaining the position and nature of the reserve food sub- 
stances. Tests were made with a saturated aqueous solution of iodine by 
allowing it to filter slowly under a cover-slip, the material being mounted 
in water and under observation with the immersion lens. Diffused through 
the cytoplasm of those cells which were actively elaborating, there appeared 
a pale pink colour, which deepened to a brilliant wine-red, and then to an 
almost violet tone. The outer portion of the chromatophore became 
a brilliant saffron-yellow and the pyrenoid a dark blue-green. As the 
iodine became stronger, the whole contents of the cell stained a deep brown, 
completely disguising the colours first obtained. In certain cells this 
pinkish colour did not appear, namely, in the trichomes, many terminal 
cells of filaments, carpogonia, and the stalk-cells of developing cystocarps. 
In all of these cells chromatophores are either rudimentary or absent. The 
cells of the gonimoblastic filaments showed a small quantity of this material 
diffused through the cytoplasm, the amount increasing with the develop- 
ment of the chromatophore. Ungerminated carpospores gave quite 
a strong reaction which gradually diminished as germination progressed. 
Young germ-tubes failed to show the reaction. 
Other material was treated with chloral hydrate-iodine solution in the 
same way. This in a more striking manner than before showed the 
brilliant red to violet coloration, and strengthening the solution did not 
bring on the undesirable brown staining with the iodine to so marked 
a degree. With this substance it was possible to see more clearly the 
small granules surrounding the pyrenoid, owing to the swelling action of 
the reagent. In all cases they took on a hue exactly like that of the 
pyrenoid. This colour was extremely difficult to classify, even in sectioned 
material, when unmodified by the surrounding yellow-staining portion of 
the chromatophore, because the granules are extremely small, and both they 
and the pyrenoid so refractive as to make a correct interpretation of the 
colour impossible. Since they appear to give exactly the same reaction as 
