Bristol -Life-history and Cytology of Chlorochytr him grande, 1 23 
plasmic network. Definite nuclear structures cannot be distinguished, and 
the nuclei seem to be little more than granules of chromatin, which, with 
iron-haematoxylin, stain an intense black colour in contrast to the blue 
colour of the pyreno-crystals. 
Text-fig. 2. Phyllobium sphagnicola. x 1,435. A, section of small cell showing radial 
arrangement of cytoplasm with groups of pyrenoids between the rays, (stained with Delafield’s 
haematoxylin) ; b, section of larger cell stained with Heidenhain’s haematoxylin to show the 
pyrenoids; the cytoplasmic reticulum is irregular, a. attachment of branching thallus; n. nucleus'; 
p. pyrenoid. 
In a few cases a somewhat radial arrangement of the cytoplasmic 
reticulum has been observed (Text-fig. 2, A), but this is most frequently 
obscured, probably by the distortion caused by the growth of the pyrenoids. 
