66 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 26 



what incurved in youth; cortical bands somewhat tumid, about 2/3 as 

 long as broad, separated by internodal spaces of 40 /x or less above, but 

 sometimes to 150 [x below (or rarely to 700-800 /x in unusual plants of 

 lax habit), divided in the lower third into two parts by a clear line, 

 the cells in the lower third often at first horizontally elongated, but 

 ultimately divided into small, angular cells, the upper part of the band 

 consisting of several larger, deep-seated cells cutting off smaller cells 

 toward the top and outside of the band; tetrasporangia whorled, 2-6 at 

 a node, about 30 jx in diam., borne within the tumid upper 2/3 of the 

 divided cortical band which becomes modified by their expansion to 

 form an involucre; old branches bearing empty involucres appearing 

 catenate; spermatangia borne in a more or less continuous superficial 

 layer of terminal branches above the region of internodal elongation, 

 tending to be confined to adaxial surface; cystocarps borne terminally, 

 surrounded and completely overarched by 5-6 long, clasping, involucral 

 branches. 



Type: E. Y. Dawson 3393, Nov. 9, 1946, in Herb. A. Hancock 

 Foundation (48797). 



Type locality: Cabeza Ballena near San Lucas, Baja California, 

 Mexico. 



Mexican distribution: Pacific Baja Calif. — D. 211a, Punta 

 Descanso; D. 1644, near Punta Maria; D. 1576, 1587, Bahia Los Ositos; 

 D. 2814, 1425, Punta Santa Rosalia; D. 10339, 10342, Punta Engenio; 

 D. 6708, 7268, Isla Magdalena; Gulf of Calif.— D. 759, 786, 724, 800, 

 Isla Patos; D. 1002, 1018, Isla Partida; D. 1039, Isla Raza; D. 613, 617, 

 1878, 1898, 1957, 1961, 1962, 1969, 1982, 3520, 11004, vie. of Guay- 

 mas; D. 7176, Puerto Escondido; D. 7051, Isla Carmen, D. 3320, 3342, 

 3368, 3401, Cabeza Ballena. Sinaloa—D. 3599, 3616, 3618, 3623, 3658, 

 3675, 10823, 10830, 10837, 10926, Mazatlan. Nayarit— D. 3704, Mira 

 Mar. Guerrero— D. 3878, 3899, Acapulco; Taylor 34-581, Bahia 

 Petatlan; Taylor 39-627, White Friars Id. Oaxaca— D. 10764, Salina 

 Cruz. 



Ceramium vagabunde Daws. 

 PI. 27, fig. 5 

 Dawson 1957, p. 121, fig. 27e, Dawson 1954a, p. 6, pi. 4, fig. 2 (as 

 Ceramium sp.) 



Plants minute. 4-5 mm. high, growing among other tufted algae, 

 consisting of a creeping semi-prostrate basal filament provided with 

 numerous ventral rhizoids from the nodes, giving rise to irregularly 

 and sparsely branched erect branches with blunt, non-forcipate tips; 

 erect axes 120-140 jx in diameter, incompletely corticated, the internodes 

 bare for intervals of 30-70 p. in the middle and lower parts; cortical 

 bands 1.5-2.0 times as broad as tall, without secondary growth above 

 or below, the margins even, especially the lower ones, truncate, consisting 



