180 COLLINS AND HOWE: SPECIES OF HALYMENIA 
0.6 mm. in diameter, and to the naked eye they sometimes look a 
little as if they might be cystocarps. A filamentous short-celled 
Rhodophyceous endophyte sometimes forms dense subglobose or 
irregularly lobed glomeruli in the medulla and these also may 
have the superficial appearance of being cystocarps of the Haly- 
meni. 
Halymenia pseudofloresia, like H. bermudensis, is commonly 
found in an unattached condition, and possibly the absence of 
cystocarps is in some way associated with this fact. The senior 
author has noted that Delesseria sinuosa and certain other mem- 
branaceous Rhodophyceae are commonly sterile when found in 
places where they have apparently been vegetating for some time 
unattached. 
Specimens of Halymenia pseudofloresia, with occasional ex- 
ceptions as to parts of the old fronds, adhere firmly to paper 
when dried under pressure. 
Halymenia echinophysa sp. nov. 
Thallo pallido-vinaceo vel lilacino, membranaceo, gelatinoso, 
125-200 u crasso (madefacto), circumscriptione suborbiculari, 
10-18 cm. diam., profunde, irregulariter vel subpalmatim lobato, 
lobis itregulariter obovatis vel suborbicularibus, marginibus 
sinuato- vel eroso-dentatis; medulla frondis subvacua vel laxe 
filamentosa, filamentis homogeneis, 10-14 p diam.; strato corticali 
gelatinoso translucido, submonostromatico, eevhutie superficialibus 
ovoideis, subglobosis vel ellipsoideis, 4-8 u diam. max., 5—10 p inter 
se distantibus, in membrana communi harizontaliter vel verti- 
caliter positis, parietibus exterioribus (vel membrana superficial 
extra-cellulari) 10-18 u crassis; strato subcorticali 2-4-stromatico, 
cellulis arcte anastomosantibus, ovoideis, ellipsoideis, vel cma 
complanatis, extimis 6-10 » diam., intimis 25-65 « diam. max 
nonnullis subglobosis, 80-180 » diam., echinato-stellatis, in me- 
dullam peebionnon, processubus 15-40, subrigidis, subspines- 
centibus, munitis 
Species H. ee M. A. Howe proxima, sed differt thallo 
minore, crassiore, magis lobato, non-nitente, membrana super- 
ficiali communi duplo crassiore, cellulis superficialibus inter se 
duplo distantioribus, filamentis medullaribus dimidio minus 
crassis et minus regulariter et minus manifesto capitatis in strato 
subcorticali abientibus, cellulis intimis strati subcorticalis saepe 
