120 
PACIFIC SCIENCE, Vol. IV, April, 1950 
Fig. 2. Antithamnion basisporum Tokida and Inaba, sp. nov.: a and b, mode of branching in the 
upper portion of a frond; c and d, mode of branching in the lower portion of a frond and young 
branches arising from the lowest cell of the pinna ( 1 ) ; c, rhizoidal filaments: three pinnae which bear 
on their lowest cells a short pinnula (2), and the branch apices, are also shown, a, b , and d, X 150; 
c, X 137. 
diam., with cells 1-4 diameters long; pinnae 
simple or rarely once divided, rounded at 
apices, 7-14 (-16) -celled, up to 14 /jl diam., 
with cells 1-3 diameters long, provided with 
gland cells which sit singly on the upper lat- 
eral side of the cell; chromatophores a few 
bands; tetraspores sessile on the basal cells of 
pinnae, 28-38 /x X 56-64 /x, cruciate ly di- 
vided; sexual reproductive organs unknown. 
Japanese name: Niretsu-kasanegusa 
(nom. nov.). 
Type: Growing on pebbles, Mera, Prov, 
Boshu. T. Inaba 401, Apr. 10, 1944 (Her- 
barium, Dept. Fish., Hokkaido IJniv.). 
This species of Antithamnion is one of 
those bearing simple pinnae. It differs from 
many of the allied species, e.g., A. glanduli- 
ferum Kylin, A. pacificum (Harv.) Kylin, 
A. Gardneri De Toni, etc., in having one to 
two tetrasporangia on the lowermost cell of 
