Lewis . — The Life History of Griffithsia Bornetiana. 641 
plants has been noted in Laurencia by Phillips (61), in Polysiphonia at 
Naples by Oltmanns (59, i, p. 650), and in Corallina by Solms-Laubach (74). 
Professor Farlow states that among the red algae, 4 tetrasporic plants are 
a good deal more common than sexual plants, and, in decidedly the majority 
of species which I have examined, I have had to look through a mass 
of tetrasporic plants before coming to any bearing sexual organs. In the 
great majority of Florideae the chances are decidedly in favour of finding 
tetraspores rather than sexual organs.’ 1 
Methods. 
Of various fixing fluids employed, the weak chrom-acetic-osmic acid 
mixture was found to be best for cytological details (Yamanouchi, 92, 
p. 425). The time of fixation varied from one to ten hours. Paraffin 
sections 3 and 5 /x thick were used almost exclusively for the finer details of 
cell structure ; grosser anatomical features were found to be best made out 
from mounts in toto. The most successful stain employed was Heidenhain’s 
iron alum haematoxylin (2 hours in the alum solution, 4 hours in the stain), 
followed by eosin in clove oil, as recommended by Miss Fraser (31). 
Difficulty was experienced in obtaining material showing abundant 
nuclear figures. Plants brought into the laboratory and fixed at all hours 
after having been kept in running water showed almost no mitoses. Finally 
favourable material was obtained by fixing 4 in the field ’ at eleven or 
twelve o’clock at night. 
Vegetative Characters. 
The thallus forms a hemispherical tuft, and is composed of much- 
branched filaments, which are made up of large swollen cells placed end to 
end in series. The filaments radiate from a common point of attachment, 
the holdfast. In a plant of average size, from the base to the apex of 
a single filament, exclusive of the branches, there are twenty to thirty cells ; 
in large specimens the number of cells in a single filament may be twice as 
great. 
The cells differ greatly in shape and size in different parts of the 
filaments (Fig. 4). Toward the base of the plant they are approximately 
cylindrical below and much swollen toward the upper end. The cells 
nearer the tip of the filament become shorter and relatively thicker, of 
an obovate shape, and of a deeper colour. Those cells of the female plant 
which bear the older cystocarps become very much swollen toward their 
upper ends. In the male plants the terminal cells bearing the antheridia 
are almost globose. The following table gives a general idea of the sizes of 
the various cells in a filament composed of twenty cells. 
1 From a personal letter. 
