NO. 1 TAYLOR: PACIFIC MARINE ALGAE 181 



These plants somewhat resemble some forms of L. pallescens of the 

 Gulf of California, and more strongly L. Kostchyanum of the Persian 

 Gulf and L. praetextatum of Easter Id, (Foslie 1929, p. 37), but in these 

 species the cells of the medulla are very much shorter than those in this 

 Galapagos plant. In it they are conspicuously elongate, even about 15 

 times as long as w^ide. The zones they form are not of the same width 

 throughout, but while they vary a good deal they do not alternate broad 

 and narrow in any regular pattern. Long cells approaching this are found 

 in the lamellate L. decussatum (Lemoine 1911, p. 139, fig. 69) and the 

 slender terete branched L. byssoides (Lemoine 1911, p. 132, fig. 64), but 

 are by no means equally long. 



Ecuador: Archipielago de Colon, in intertidal pools, occasional at 

 Black Beach Anchorage, I. Santa Maria, no. 34-234A (TYPE), 17 Jan. 

 1934. 



Lithophyllum moluccense Foslie, v. geminostratum n. var.^^^ 



Plate 44 



Plant with a thin crustose base, but the crust commonly destroyed, 

 bushy above, forming masses a few centimeters in diameter ; erect branches 

 moderately crowded, to about 2-3 cm tall, irregularly dichotomously 

 branched, terete and 0.75-2.50 mm diam., or occasionally fasciate-com- 

 planate and 2-3 mm wide, below frequently anastomosing, above the 

 apices blunt; conceptacles crowded on the sides of the outer segments, 

 only very slightly convex, about 200 fx diam., with a single pore ; in section 

 (apparently spermatangial) conceptacles immersed, 170-200 jx diam., the 

 height about 40-60 /x, the floor flat, the roof moderately arched; peri- 

 thallus of cells 5-6 p. diam., 6-10 fi long, in moderately regular layers; 

 medulla notably and regularly zonate, each zone one cell thick, the 

 broader zones alternating with 1-2 narrower ones, composed of cells 6-9 fi 

 diam., 20-115 jx long. 



This plant seems to be related to L. moluccense Foslie. It shows con- 

 siderable superficial resemblance to the f. pygmaea (Heydrich) Foslie 

 (1904, p. 67, pi. 12, figs. 7, 12-13). Structurally it shows alternating 

 bands of very long and shorter cells described for L. moluccense (Foslie 

 1904, p. 67, fig. 26; Lemoine 1911, p. 135, figs. 65-67), but the alterna- 



105 Lithophyllum moluccense Foslie v. geminostratum n. van— Plantae botry- 

 ones paucorum cm diam., 2-3 cm crass, formantes ; copiose irregulariterque dicho- 

 tome ramosae, ramis teretibus obtusisque, 0.75-2.50 mm diam.; cellulis penthalli 

 5-6 \x diam., 6-10 ^ long.; medulla notabiliter irregulariterque zonata, zonis latis 

 atque duabus angustis plerumque alternantibus, cellulis 6-9 \x diam., 20-115 ^ 

 long. Planta typica in loco dicto I. Santa Maria, Ecuador, legit W. R. Taylor 

 no. 24-234B. 17 Jan. 1934. 



