Benthic Algae — D awson 
439 
Antithamnion mcnahhii Dawson 
Dawson, 1959 
Bahia Agua Verde, Gulf of Calif. 
Antithamnion nigricans Gardner 
'Scagel, 1957 
Vancouver I., British Columbia 
Antithamnion occidental Kylin 
Taylor, 1945; Scagel, 1957 
Alaska to La Jolla, Calif.; Galapagos Arch. 
Antithamnion pacificum (Harvey) Kylin 
Dawson, 1954; Scagel, 1957 
Yakutat Bay, Alaska, to La Jolla, Calif.; north- 
ern Gulf of Calif. 
Antithamnion pulchellum Gardner 
Gardner, 1927c 
Santa Monica, Calif. 
Antithamnion pygmaeum Gardner 
Doty, 1947; Dawson, 1949; Dawson, Neushul 
& Wildman, 1960^ 
Oreg. to Punta Eugenio, Baja Calif. 
Antithamnion secundatum Gardner 
Gardner, 1927c 
San Diego, Calif. 
Antithamnion setaceum Gardner 
Gardner, 1927c 
San Diego, Calif. 
Antithamnion simulans Gardner 
Gardner, \921b 
Sitka, Alaska 
Antithamnion sublittorale Setchell & Gardner 
Dawson, 1954 
San Jose del Cabo, Baja Calif. 
Antithamnion suhulatum (Harvey) J. Agardh 
Scagel, 1957 
Southern British Columbia to Monterey, Calif. 
Antithamnion uncinatum Gardner 
Scagel, 1957 
Northern Wash, to Carmel, Calif. 
Antithamnion veleroae Taylor 
Taylor, 1945 
Galapagos Arch. 
Platythamnion heteromorphum (J. Agardh) J. 
Agardh 
Doty, 1947 
Oreg. to San Pedro, Calif. 
Platythamnion pectinatum Kylin var. pectinatum 
Dawson, 1954; Scagel, 1957 
Hope I., British Columbia, to Cabo Colnett, 
Baja Calif. 
Platythamnion pectinatum var. laxum Taylor 
Dawson, 1954 
Isla Clarion, Revillagigedo Arch. 
Platythamnion reversum (Setchell & Gardner) 
Kylin var. reversum 
Scagel 1957 
Northern Wash, to Oreg. 
Platythamnion reversum var. laxum Taylor 
Taylor, 1945 
Galapagos Arch. 
Platythamnion tepocensis Dawson 
Dawson, 1954 
Bahia Tepoca, Gulf of Calif. 
Platythamnion villosum Kylin 
Dawson, 1954; Scagel, 1957; Dawson, Neu- 
shul & Wildman, 1960a 
Sitka, Alaska, to Bahia Tortuga, Baja Calif. 
Ceramium affine Setchell & Gardner var. affine 
Taylor, 1945; Dawson, 1954 
Isla Guadalupe, Baja Calif.; Isla Angel de la 
Guarda, Gulf of Calif.; Guayas, Ecuador 
Ceramium affine var. peninsularis Dawson 
Dawson, 1954 
Corona del Mar, Calif.; Scammon Lagoon, 
Baja Calif.; Punta Frailes, Gulf of Calif. 
