THE PYRENOID OF ANTHOCEROS 
8l 
that it is similar chemically to nuclein. He describes the fission of 
the chloroplast and pyrenoid in Hyalotheca and believes that fission 
is the common mode of multiplication of pyrenoids although he is also 
of the opinion that they may arise from the cytoplasm de novo. Al- 
though recognizing the close relation of the pyrenoid to starch forma- 
tion he insists that it takes no direct, morphological part in the process. 
He believes the starch to be deposited at all times in the clear zone 
immediately surrounding the pyrenoid. 
The angular shape of the pyrenoid of Bryopsis pliimosa as well 
as of other forms, together with the difficulty of proving its fission, 
led Schimper (i8) to the belief that the pyrenoid is of the nature of a 
protein crystal. He agrees essentially with Schmitz as to the mode 
of the formation of starch about the pyrenoid but disagrees in part 
as to the mode of multiplication, believing that new pyrenoids are 
formed only as are new crystals, de novo. 
Boubier (2) has proposed that not only the compact central body 
but also the clear area about it should be regarded as the pyrenoid. 
The clear area he believes to be penetrated by radiating, granular 
strands. Of these granular strands he says: '*J'assimile cette sub- 
stance granuleuse a un leucite dans les mailles duquel se depose 
I'amidon." 
Wiesner (22) had earlier regarded the interior of the pyrenoid as 
made up of plastids of the nature of leucoplasts, each plastid giving 
rise to a starch grain. 
Timberlake (20) is ''inclined to the view that the pyrenoid is a 
active body, differentiated from the chlorophyll-bearing cytoplasm, 
which in co-operation with the latter acts as the basis for starch 
formation." His work on Hydrodictyon showed that segments split 
off from the pyrenoid in concentric scale-like discs. By the deposition 
of starch within these segments starch grains are formed which are 
considerably larger than the pyrenoid segment. During this process 
of starch formation the pyrenoid undergoes continual growth but at 
the same time is being reduced in size by the cutting off of rudimentary 
starch grains. The pyrenoid stains red with the safranin of the triple 
stain but at the time of the cutting off of the segments, the material 
cut off takes the violet stain, indicating thus its starchy nature. In 
Rhizoclonium, Cladophora, and Oedogonium he finds (21) that the 
pyrenoid often becomes split into halves and that either or both of 
these halves may become a starch grain, or, in some instances, the 
