396 
PACIFIC SCIENCE, VoL VIII, October, 1954 
LOCAL DISTRIBUTION: Forming congested because of its bright yellow-green tips and 
clumps on dead coral partially embedded in shining, white, calcified lower parts, 
sand, Sta. 3 (11186). 
Halimeda gracilis Harvey, ex J. Agardh 
1887: 82 (Ceylon) 
Fig. 13/ 
LOCAL DISTRIBUTION: A single fragment of 
a plant attached to a bit of Colpomenia was 
found in drift at Sta. 10 (11333). 
The segments have the shape and texture 
of those of H. gracilis f. lata illustrated by 
Taylor (1950, pi. 42) from Bikini and are 
quite identical in size with those of his small- 
est example (5-8 mm. wide). Structurally my 
specimen agrees with Taylor’s description al- 
though the cortical utricles are not particularly 
angular in surface view and are even smaller 
than he indicates (15-25 /x diam.). 
Ostreobium reineckei Bornet, in Reinbold 
1896: 269, fig. 55 (Samoa); Setchell 1924: 
256, fig. 55 
s Fig. 13g 
LOCAL DISTRIBUTION : Growing within frag- 
ments of dead coral, Sta. 1 (11304). 
This minute, filamentous, coral-boring alga 
often lends a greenish color to the coral frag- 
ments it inhabits but cannot otherwise be 
observed without decalcifying the coral. The 
irregularly shaped filaments range from 3 to 
10 fx in diameter. Several species have been 
described from different corals, and it is to 
be expected that some others may be en- 
countered at Nha Trang after careful search. 
Neomeris annulata Dickie 1874: 198 (Mau- 
ritius); Egerod 1952: 400, pi. 40, text fig. 
21a-l, 22a, c _ 
Fig. 13^ 
LOCAL DISTRIBUTION: Common in groups 
of a few to several score on dead coral frag- 
ments, Sta. 1 (11116); Sta. 3 (11210). 
This is a conspicuous, though tiny, plant 
Bornetella oligospora Solms-Laubach 
1893: 81, pi. 9, figs. 1-4, 6, 7 (Malaya); 
Gilbert 1943: 26, fig. Ig, h 
Fig. 13^ 
LOCAL DISTRIBUTION: Occasional on coral 
masses dredged from 2-3 m., Sta. 2 (11363). 
Although the aplanosporangia are imma- 
ture in these, they are spherical and numerous 
on the primary branches, as in this species 
versus B. nitida. 
Bornetella sphaerica (Zanard.) Solms-Lau- 
bach 1893: 92, pi. 9, fig. 8; Egerod 1952: 
407, pi. 42, fig. 22d-g. Neomeris sphaerica 
Zanardini 1878: 38 (Malaya) 
Fig. 13/ 
LOCAL DISTRIBUTION: A single specimen 
found on coral dredged from 2-3 m., Sta. 2 
(11384). Being sterile, this plant is referred to 
B. sphaerica rather than to B. capitata (Harv.) 
J. Ag. with some question. 
Acetabularia caliculus Lamouroux 1824: 
621, pi. 90, figs. 6, 7 (Australia); Tseng 
1936/^: 155, fig. 16. 
Fig. X'bh 
LOCAL DISTRIBUTION: Several plants at- 
tached to a shell, Sta. 4 (11172). These are 
all immature, although that illustrated has 
produced its gametangial disc and may be 
considered to be of full stature. It is about 
2 cm. high and agrees with the A. caliculus 
of Tseng (1936^) from nearby Hainan. The 
species may be recognized by its whorls of 
assimilating hairs below the basin-shaped 
gametangial disc of about 30 rays. The rays 
of my plant are not emarginate as is usual in 
this species, although such a young plant 
may not necessarily be expected to show this 
character. 
