402 
PACIFIC SCIENCE, VoL VIII, October, 1954 
Fig. 16. a, b, Dictyota friabilis: a, A portion of a thai- 
lus of 11361, showing sporangia and rhizoids with 
sand grains on the ventral surface, X 2.5; b, outline of 
part of a sterile thallus of 11389, X 1. c, Dictyota patens: 
An upper portion of a plant to show apices and mar- 
ginal teeth, X 2.3. 
de France); Weber van Bosse 1913: 178, 
fig. 51; B0rgesen 1930: 170 
Fig. 17 
LOCAL DISTRIBUTION: Small plants to 2 cm, 
tall from conspicuous 'Vaughaniella' creeping 
parts, Sta. 1 (11128); large, flabellate plants 
to 20 cm. tall on rocks, Sta. 3, 4 (11163). 
These plants have the fertile zones alternat- 
ing with hair zones as is characteristic of this 
species according to Weber van Bosse. 
Colpomenia sinuosa (Roth) Derbes and 
Solier 1856: 11, pi. 22, figs. 18-20. Viva 
sinuosa Roth 1806: 327, pi. 12 (Cadiz, 
Fig. 18^, c, d 
LOCAL DISTRIBUTION: A number of different 
forms of this species occur, often intermingled 
in a given locality. In many respects they 
suggest different species, but experience in 
other regions has taught that the specimens 
representing this range of variability cannot 
satisfactorily be separated into specific units. 
The smooth, rounded form of Figure 18^, 
which may be considered the typical form of 
the species (forma sinuosa)^ is readily recog- 
nized by its brown, bubble-like shape. Figure 
18r, d represent two examples from a con- 
siderable range of tuberculate, lobed, con- 
torted, and perforated plants. The strongly 
lobed one of Figure 18c forms dense, more or 
less hemispherical thalli to 5-6 cm. in di- 
ameter which occur in abundance alongThe 
beach at Cii Lao. The part of a plant drawn 
is a variant with rather gross protruberances. 
Other examples have smaller, more com- 
pacted lobes. Figure 18^ represents a form 
which tends to approach Hydroclathrus in its 
contorted form and perforated thallus. It is 
rather coarse in texture and has thicker walls 
than 11331, which is thin- walled and rather 
soft in texture. Although occasionally found 
elsewhere, all these forms occur in abundance 
in the shallow area just east of the village of 
Cu Lao during February. 
Fig. 17. Padma commersonii: A mature, fertile blade, 
X 0.9. 
