NO. 1 TAYLOR: PACIFIC MARINE ALGAE 187 



4 successively shorter elongate cells preceding each isodiametric cell in 

 each filament, the cells forming transverse zones; pericarps very promi- 

 nent, hemispherical or higher and commonly contracted a little at the 

 base, 230-350 fi diam., usually one to a segment and often contiguous in 

 series along a branch, occasionally two opposite on a segment. 



This tiny species is chiefly notable for the very short strictly cylin- 

 drical segments w^hich are hardly indented at the ends, and so, since the 

 flexible articulation is very narrow^, are only to be distinguished on close 

 examination. The conceptacles are relatively large and seem to be chiefly 

 superficial on the branch. 



Costa Rica: rare, littoral, Golfo Dulce, no. 39-116C (TYPE), 26 

 Mar. 1939. 



Amphiroa franciscana n. sp.^^^ 

 Plate48, Fig. 2; Plate 49 



Plants forming close clumps on shells or stones, 1.5-2.5 cm tall from 

 an inconspicuous crustose base, irregularly dichotomously branched at 

 angles of about 60°, w^ith frequent lateral branches, sometimes somewhat 

 erect, at others the branching complanate and reHexed, producing a some- 

 what rosettelike habit; the segments cylindrical to somewhat compressed, 

 especially below a fork; those supporting a dichotomy club shaped to 

 deeply forked, sometimes twice forked between articulations, sometimes 

 supporting 3 to even 4 branches terminally; diameter of segments below 

 250-375 II, near the tips 180-200 /i, length of segments near the tips 1.5- 

 2.35 mm; below 1.12-1.50 mm, but less at the extreme base; where com- 

 pressed, the thickness one fifth to more often about two thirds the width ; 

 conceptacles prominent, about hemispherical, to 250-260 /* diam., most 

 commonly placed along the margins of the compressed branches, to 2-7 

 on a side; medullaiy structure showing an alternation of 4 (sometimes 3 

 or 5) zones of large cells of decreasing length between each zone of very 

 small cells and the next zone above. 



Mexico : Nayarit, frequent on large rocks as dredged from 24 meters' 

 depth at sta. 970, I. Maria Magdalena, Las Tres Marias, no. 39-643 J, 

 9 May 1939. Ecuador: Esmeraldas, dredged from 5.4 meters' depth 

 oflF Ba. San Francisco, no. 34-484 (TYPE), 11 Feb. 1934. Guayas, on 

 the southeast side of Pta. Santa Elena, Salinas, no. 34-471, 8 Feb. 1934. 



108 Amphiroa franciscana n. sp. — Plantae caespitosae, 1.5-2.0 cm altitudine, 

 e basi crustosa orientes, irregulariter dichotomae, ramis lateralibus frequentibus; 

 segmentis cylindricis ad paululum compressa, iis dichotomiam sustinentibus clavatis 

 ad profunde furcata, diametro infra 250-275 \i, supra 180-200 \i, longitudine infra 

 1.12-1.50 mm, supra 1,50-2.25 mm; conceptaculis prominentissimis, 240-260 \i diam. 

 Planta typica in loco dicto Ba. San Francisco, Esmeraldas, Ecuador, legit. W. R. 

 Taylor no. 34-484, 11 Feb. 1934. 



