512 HOWE: PHYCOLOGICAL STUDIES 
ment, in fact, the diameter of the filament commonly suffers a 
slight diminution at the nodal point; the cells of the subcortex have 
substellate anastomosing branches, but the cells are very small in 
comparison with the corresponding cells of Halymenta actinophysa 
and they rarely have more than 3 or 4 branches. The cortex of 
the New Zealand Aeodes nitidissima consists of distinctly anti- 
clinal moniliform filaments of which the ultimate peripheral cells 
are, as described by Agardh, decidedly narrower than the sub- 
jacent cells (‘‘exterioribus conspicue angustatis’’); these cells are 
only I-34 in diameter when viewed from the surface, but in a 
cross section of the thallus are seen to be about twice as high as 
broad. It may be remarked that in the specimens from Whidbey 
Island, Washington, distributed in the Phycotheca Boreali- 
Americana (no. 946) as Aeodes nitidissima J. Ag., the cells of the 
cortex may hardly be described as being in distinct anticlinal rows, 
and the ultimate peripheral cells instead of being conspicuously 
narrower than those immediately subjacent are of equal width or 
even broader and have 2-4 times the diameter of the corresponding 
cells in the New Zealand plant. 
The dried specimens of Halymenia actinophysa adhere very 
firmly and intimately to paper. The cell walls are so gelatinous 
and translucent that one gets little idea of the real structure of the 
thallus by examining an ordinary section in water or in water and 
glycerin—at least until one has learned otherwise what to expect 
and look for; but by staining sections or fragments with haema- 
toxylin and afterwards swelling out the more or less collapsed cells 
by applying alittle potassium hydrate or picric acid, the relations 
of the parts become manifest. 
NEw York BOTANICAL GARDEN. 
Explanation of Plates 27-34 
PLATE 27. Dictyota Vivesii 
A photograph of a portion of the type specimen (La Paz, Vives 2), natural size. 
The stipe is shown towards the lower right-hand corner. 
PLATE 28. Scinaia latifrons 
A photograph of a portion of the type specimen (La Paz, Vives Ira), nine 
tenths of the natural size. The cystocarps are visible near the margins in the median 
portions. See also FIGURE 1 (in text), which shows a better mounted, though 
mutilated specimen. 
