212 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



Prionitis albemarlensis n. sp.^^^ 

 Plate 68, Fig. 2 



Plants clustered, from pulvinate holdfasts rising to a height of 3 dm, 

 dull purplish red, in texture fleshy membranous above, subcartilaginous 

 below; axes briefly slender and compressed below, flat and subfoliar above, 

 irregularly but chiefly alternately marginally branched, the axes and 

 branches lanceolate to subcuneate, the branches sometimes sharply con- 

 tracted at the base but often not contracted, especially in the main divi- 

 sions, the margins plane or a little undulate; structurally of closely packed 

 slender thick-walled filaments in the medulla, the filaments thicker out- 

 wardly and bearing close radial rows of cells square in transverse section, 

 to form the firm cortex. 



These plants suggest P. Lyallii, but they seem to branch more widely 

 from the base. They show a little tendency for concatenate branching, but 

 give ofif lateral divisions with plane bases moderately or not contracted, 

 and the divisions seem thinner and softer than those of P. Lyallii. 



Ecuador: Archipielago de Colon, intertidal on a reef to the north 

 of Tagus Cove, I. Isabela, no. 34-163 (TYPE), 13 Jan. 1934. Ibid., 

 intertidal on rocks near Black Beach Anchorage, I. Santa Maria, no. 34- 

 2275, 17 Jan. 1934. 



Prionitis galapagensis n. sp.^^T 

 Plate 68, Fig. 1 



Plants clustered, to 15-18 cm tall, the holdfasts small, pulvinate, the 

 erect portions compressed below, flat above, fleshy membranous to sub- 

 cartilaginous, dull purple in color; branching irregularly pinnate, the 

 lower branches approaching the chief axis in length, all simple, subsimple, 

 or to moderately closely marginally bearing small simple or one-forked 

 branchlets; main axes and branchlets linear lanceolate, to 5-10 mm wide, 

 the margins nearly plane to closely and strongly crisped; axis densely 

 filamentous, the slender filaments closely conjoined by their thick walls, 

 outwardly pseudoparenchymatous and bearing a firm cortex of anticlinal 

 rows of cells nearly square in section. 



126 Prionitis albemarlensis n. sp. — Plantae ad 3 dm altitudine, fasciculatae, 

 irregulariter, alterne marginaliter ramosae, segmentis supra subfoliaribus, carnosis, 

 lanceolatis ad subcuneata, ad basim plerumque non contractis, marginibus fere 

 planis. Planta typica in loco dicto I. Isabela (anglice Albemarle I.), Ecuador, 

 legit W. R. Taylor no. 34-163, 13 Jan. 1934. 



127 Prionitis galapagensis n. sp. — Plantae ad 15-18 cm altitudine, fasciculatae, 

 irregulariter pinnate ramosae, ramis inferioribus ad axem primarium longitudine 

 accedentibus, segmentis supra planis, carnoso-membranaceis, simplicibus aut ramu- 

 lis parvis in margine modice praeditis; axe primario ramisque lineari-lanceolatis, 

 marginibus valde arcteque crispis farctis. Planta typica in loco dicto Black Beach 

 Anchorage, I. Santa Maria, Ecuador, legit W. R. Taylor no. 34-221 A, 17 Jan. 1934. 



