Herposiphonia of Tropical Pacific — Hollenberg 
553 
numerous collections listed herewith are readily 
referable to H. parca, although more segments 
commonly occur in the determinate branches 
than are present in the type material. 
Considerable variability occurs among the 
various collections. Frequently encountered are 
more slender forms with up to 20 segments in 
the determinate branches and with the segments 
2 or more diameters long. These variants are in- 
dicated in the following account with an aster- 
isk. In some of these there are only 6 peri- 
central cells in the segments of the determinate 
branches. Another variant has indeterminate 
branches up to 3 times the diameter of the de- 
terminate branches. These are marked with a 
dagger (f) and are designated as form dispar. 
COLLECTIONS EXAMINED: HAWAIIAN ISLANDS 
- — D. 19l44L4*f, dredged 6-12 fa, Port Allen, 
Kauai, Sept. 12, 1959; a collection by Gary Col- 
lins, tetrasporic, on Galaxaura sp., Haena Beach, 
Kauai, Apr. 16, 1965; D. 8904*f, 8905.1*f, 
in connecting channel of holding ponds, Coco- 
nut I., Kaneohe Bay, Oahu, Oct. 13, 1951; D. 
1082lA*f, on a boat just below the water 
line, Kaneohe Bay, Oahu, Oct. 7, 1953; D. 
19135AAl*f, D. 19136Flf, dredged at 15 fa, 
in front of river mouth, Waialua, Oahu, Aug. 2, 
1959; D. 19706.1, awash at Kailua Beach, 
Oahu, Sept. 20, 1962; D. 20047.1, on rocks, 
Laie, Oahu, legit R. Tsuda, G. Trono, and R. 
Buggeln, May 5, 1963; H. 65-65, sperma- 
tangial, on C odium sp., bottom of large tide 
pool, Wawamalu Beach, Oahu, May 1, 1965; a 
collection by Gary Collins, tetrasporic, dredged 
at 2-3 fa, Kaneohe Bay, Oahu, Mar. 20, 1965 ; 
D. 22301.2, in a tidepool, northeast bench, 
Hanauma Bay, Oahu, legit R. Tsuda, Feb. 17, 
1965; D. 19137A1*, spermatangial, dredged at 
15-20 fa, Ilio Point, Molokai, Sept. 7, 1959; 
D. 22384, D. 22389, D. 22390.1, on other 
algae, basalt shore, near Maalaea, Maui, legit 
H., T., and B., Apr. 19, 1965; D. 17063.1, on 
Amansia, on wave-dashed basalt, Pohoiki, Puna, 
island of Hawaii, Jan. 27, 1953; D. 20193.5, in 
algal turf, Kaena ponds, Kaena, Puna, island of 
Hawaii, Mar. 19, 1965 ; a collection by John 
Fitzsimons, on other algae, Kapoho, island of 
Hawaii, Mar. I, 1965 ; johnston island — H. 
65-118*, tetrasporic, H. 65-136, tetrasporic, 
spermatangial, on dead coral at a depth of 1-2 
m, 20 m shoreward from the outer reef margin, 
north of North Island, legit R. S. Jones, Apr. 22, 
1965; line islands — L. 2703.6*, on Laurencia 
sp., on exposed coral heads, Jarvis I., Nov. 16, 
1964; society islands — D. 12095.1, D. 
12099.1, on other algae, under coral boulder, 
lagoon shore, Arue Pt., Tahiti, Sept. 15, 1952; 
FIJI ISLANDS— D. 12123.1*, in algal turf, Na- 
vuevu Cuvu, Singtoka, Viti Levu, Sept. 22, 
1952; GILBERT ISLANDS — D. 18904.1*f, tetra- 
sporic, Abemmama I., legit M. J. Cooper, July, 
1962; MARSHALL islands — D. 12723.1, on 
other algae, seaward reef, Parry I., Eniwetok 
Atoll, July 24, 1954; G. 749.1, at a depth of 
9 m, lagoon reef, Eniwetok Atoll, Sept. 7, 1955 ; 
H. 48-Y58.21, on other algae, Runit I., Eni- 
wetok Atoll, July 27, 1948; Caroline islands 
• — all legit Ernani Menez, I960; D. 21838.2, on 
other algae, reef flat at Epwelkapw, Ponape 
(6° 59'N, 158°11'E), June 16; D. 15071.1, on 
Amphiroa sp., on reef, eastern side of Man- 
tapeitak I. (7°15'N, 158°18'E), June 20; D. 
21046J, tetrasporic, on sea grass, south end of 
Moen I., Truk group, Aug. 1 ; D. 23656.2, on 
Padina sp., reef at Falas I., Truk group (7°32'N, 
151°45'E), D. 23804.1, on branching coralline, 
Falas I., D. 23811, on branching coralline, Falas 
I. , all July 30; D. 23648.1, on dead coral, 
Dublon I., Truk group, July 31; D. 23253.2, on 
dead coral, southern tip of Sorol I. (8°8'N, 
140°4'E), Aug. 13; D. 23359.1, D. 23471.3, 
D. 21857.3*, on other algae, reef at Yap I. 
(9°29'N, 138°8'E), Aug. 13; D. 15586.2*, 
tetrasporic, D. 15556.2, spermatangial, on Sar- 
gassum sp., on reef, Koror I., Palau group, Sept. 
5; D. 15981.1*, tetrasporic, on Padina sp., on 
reef at Iwayama Bay, Palao I. (7°20'N, 134° 
31'E), Aug. 22; D. 15576.2, on Padina sp., D. 
15654.1, tetrasporic, on other algae, D. 21721, 
on other algae, all from reef flat, Pulo Anna I., 
Sept. 3; D. 15398A1, on Turbinaria, south end 
of Helen Reef (2°48'N, 131°45'E), Aug. 28; 
PHILIPPINE ISLANDS — D. 181 03B, 181 03C, on 
other algae at a depth of 3-6 ft, near Davao, 
Mindanao, June 22, 1958; three collections by 
D. P. Abbott, 1957, a tetrasporic specimen from 
sand flats east of Laminusa I., Siasi, Sulu Sea, 
Jan. 29, sterile specimens on a reef flat west of 
Cagayan, Sulu Sea, Feb. 28, and spermatangial 
and cystocarpic specimens from Gnat Reef, Bala- 
bac I., Mar. 4; GUAM — D. 20135, D. 20136, on 
