Pacific Species of Antith amnion — Tokida and INABA 
123 
Fig. 4. Antith amnion cristirhizophorum Tokida and Inaba, sp. nov. Middle portion of a main branch 
showing pinnae, pinnulae, gland cells, and rhizoidal filaments. X 100. 
quam etiam pinnula singula simplici vel ra- 
mose ornatis; pinnis transversalibus laterali- 
bus minoribus, irregulariter ramosis; pinnulis 
ultimis subulatis, cellulis apicalibus ca. 5 p 
crassis; ramis principalibus usque ad 120- 
160 pi crassis, cellulis diametro 1-3-plo lon- 
gioribus, cellulis apicalibus 14 p aids, 10-12 
p crassis, cellulis basalibus superiore (interi- 
ore) latere plerumque nulla pinna laterali 
ornatis; cellulis glandulinis numerosis, supra 
unam cellulam lateraliter sitis, usque ad 34 p 
X 30 p; chromatophoris numerosis, taeni- 
atis; rhizoidibus a cellulis basalibus pinnarum 
inferiorum emittentibus, 10-30 p crassis; te- 
trasporangiis in pinnis sessilibus, 36 ^ X 
34 p, cruciatim divisis; spermatangiis et ra- 
mulis carpogonatis ignotis. 
Frond up to 2 cm. high, repeatedly sub- 
dichotomously branched, with whorls of four 
pinnae; the two lateral pinnae in mature 
stages very short, 80-200 p long, 22-46 p 
diam. at the base, with 5-7-celled axis, which 
is oblanceolate, pectinate on the upper side, 
with two rows of branched pinnulae in the 
lower portion, sometimes with also a single 
pinnula, simple or branched, on the lower 
side of the basal cell; the two transverse pin- 
nae smaller than the lateral ones, irregularly 
branched; ultimate pinnulae subulate, ca. 5 p 
diam. at the apex; main branches up to 120- 
160 p diam., with cells 1-3 times as long as 
broad, apical cells 14 p long, 10-12 p diam., 
basal cells usually with no lateral pinna on 
the upper (inner) side; gland cells numer- 
ous, sitting laterally on one cell, up to 34 p 
X 30 p; chromatophores numerous narrow 
bands; rhizoids produced from the basal cells 
of lower pinnae, 10-30 p diam.; tetrasporan- 
gia sessile on pinnae, 36 p X 34 p , cruciately 
divided; sexual organs unknown. 
Japanese name: Oni-no-yotsubagusa 
(nom. nov.). 
Type: Growing on the shells of Ostrea, 
collected off the shore near the Fisheries 
School, Tateyama, Prov. Boshu. T. Inaba 403 , 
Apr. 18, 1944 (Herbarium, Dept. Fish., Hok- 
kaido Univ.). 
One of the leading characters of this new 
species is that the larger (pinnae laterales) 
of the two pairs of pinnae is comparatively 
short, usually 1-1.5 times, but rather rarely 
more than two times, as long as the diameter 
of the cells of the main axis. Since both the 
lateral and transverse pinnae are short and 
adorned with ultimate ramuli, which are 
sharply acute at their apices as in other 
