NO. 10 DAWSON : MARINE ALGAE, GULF OF CALIFORNIA 335 



description of his Pterosiphonia calif ornica (1941, p. 39), which is said 

 to be coarser, with a main axis 250-300 fi thick, and with shorter and 

 thicker lateral branchlets. The Mexican plants do not measure over 150 

 /i in thickness and have quite the same size and proportions as the Euro- 

 pean examples of P. pennata. 



D. 372, dredged in 22 meters, Tepoca Bay, Feb. 



Pterosiphonia dendroidea (Mont.) Falk. 



Falkenberg, 1901, p. 268; Taylor, 1939, p. 16. Polysiphonia dendroidea 

 Kutzing, Tab. Phyc. XIII, tab. 25a-b. 



A few fragments, apparently of young material of this species, occur 

 in recent Mexican collections, partly growing with Pterosiphonia 

 pennata. 



Schmitt, from 12-20 meters, Punta Gorda, and from San Jose del 

 Cabo, July 19, 1938; D. 260, dredged in Mejia channel, 12-22 meters, 

 Puerto Refugio, Jan.; D. 372a, dredged in 22 meters, Tepoca Bay, Feb. 



Genus VELEROA gen. nov. 



Frondes graciles, minutae, sparse ramosae, axi polysiphoniacea, monopodica, 

 cellulis pericentralibus 4, ramos laterales, magnos, determinatos, persistentes, col- 

 oratos, raonosiphonios in % spira instructos, emittente; tetrasporangiis in spira 

 singula ordinatis, uno per segraentum, in partes superas, leviter turgidas axiura 

 priraariarum; stichidiis propriis deuntibus. 



Slender, minute, sparingly branched plants, consisting of a polysipho- 

 niaceous, monopodial axis of four pericentral cells bearing large, determi- 

 nate, persistent, colored, monosiphonous lateral branches in a i/4 spiral; 

 tetrasporangia borne in a single spiral row, one per segment in slightly 

 swollen upper portions of main axis ; no stichidial branches produced. 



Type : Veleroa subulata. 



This genus is nearest to Lophocladia in the subfamily Lophothaliae. 

 It differs in the occurrence of sporangia in the main axis without the de- 

 velopment of specialized stichidial branches. 



Veleroa subulata sp. nov. 

 Plate 72, Fig. 2 



Frondes 10-15 mm. altae; cellulis pericentralibus 50-70 \i diam. ; ramellis 

 lateralibus 400-700 \i longis, 25-40 \i diam., subulatis, cellula apicali acuta. 



Plants 10-15 mm. high, monopodial, with a sparingly branched, poly- 

 siphonous main axis and large, persistent monosiphonous, colored, lateral 



