GRATELOUPIACEAE 159 
Family GRATELOUPIACEAE 
HALYMENIA Ag. p.p. Syn. Alg. Scand. хіх. 1817. J. Ag. Anal. 
Alg. 53. 1892 
Halymenia tenera sp. nov. 
Plane, gelatinous-membranous, suborbicular (?), 2-5 cm. (or 
more?) wide, very thin (100—150 и), extremely delicate and fragile, 
commonly rugose, minutely scrobiculate, or subfenestrate, the 
margins subentire or sinuate-dentate, soon becoming erose or 
erose-lacerate; medulla gelatinous but moderately compact, its 
filaments rather homogeneous, 6-13 и in diameter, or 22-28 u 
ircluding the outer soft deliquescing gelatinous layers of the cell 
walls, subdichotomous or laterally branched, occasionally stellate, 
interwoven, conglutinate and anastomosing, the cells mostly 35- 
90 и long; subcortex of опе or two series of irregularly ellipsoid, 
trigonous-pyramidal or substellate anastomosing cells about 18- 
30 и in longest diameter (which is commonly parallel to surface); 
cortex 3-5 cells thick, composed of short filaments, nearly every 
cell (below the surface) bearing 2 or 3 rather patent branches, the 
terminal (superficial) cells (protoplasts) ellipsoid or obovoid, ob- 
tuse, mostly 1.5-2 times as long as broad, 8—11 и in longest 
(usually ще diameter, in surface view elliptic, angular- 
elliptic, or ovate, 5-9 и in maximum diameter, separated by hya- 
line intervals 1-6 и broad; sporangia (protoplasts) 10-25 и 
Х 11-19 и, the spores decussately or now and then Паста 
paired. 
“Dredged in about five fathoms," Bay of Sechura, April 8, 
1907, Coker 157 p.p. Only fragments were obtained, so that we 
are unable to give a full description of the form and size of the 
complete plant. Тһе thallus, in fluid-preserved material, is 
wrinkled, furrowed, ridged, pitted, and falsely bullate, though 
these characters are less obvious after the specimens have been 
pressed and dried. The plant is remarkable for its extreme 
delicacy and the ease with which it becomes torn and lacerate; 
it adheres very firmly to paper in drying. Superficially, the species 
might appear to fall in the Hymenopsis section of the genus with 
Halymenia latifolia Crouan, Н: ulvoidea Zanard., and H. actino- 
physa М. A. Howe, yet the cortex is more distinctly filamentous 
and less monostromatic than in any of these species and the thallus 
is softer and more tender than in any of these. We are inclined to 
place the plant in the same section with the type of the genus, 
