[2. 
ia, 
14. 
15. 
16. 
IZ2 
Filaments unbranched, oad fine, somewhat ser 
to the touch 508 368 ; : : : 13 
Filaments coarse, visible to he Aaa eye as then bono 
or unbranched ... ae Soe ae Soe so: sion lee 
Filaments of a single row of cells, of uniform width throughout, 
with band-shaped chromatophores and conspicuous pyrenoids 
imseachn cell” i .. Sicha as sae Ulothnix ...p.48 
Filaments of a single row of ceils of varying diameter, only the 
narrowest shewing band-shaped chromatophores. Wider 
parts of the filaments divided into narrow discoid or completely 
spherical cells (usually reproductive) ... Urosporva ...p. 49 
Filaments branched ec = fo 7s eh ie SG 
Filaments unbranched siete ae oe 508 = ..-  tG 
Thallus of two to four rows of cells, forming a multicellular 
filament, sometimes twisted, not hollow and only occasionally 
branched ae 500 50 S50 Percursaria ...p.46 
Thallus branched, tubular, formed of small cells arranged as 
in parenchyma 505 sn Enleromorpha  ...p. 47 
Thallus of semi-coenocytic alae forming a tangled mass ; 
filaments provided here and there with short, recurved, 
hook-like branches ate ae ... Rhizoclonium ...p.51 
Thallus of semi-coenocytic filaments with a high degree of 
branching skid as ie ee Cladophora ...p.52 
Filaments of a single row of large semi-coenocytic cells... 
Chaetomorpha ...p.50 
Filaments two to four cells in breadth, sometimes twisted, 
not forming a tube 355 bob BSD Percursavia ...p. 46 
PHAEOPHYCEAE. 
Filamentous plants not microscopically small, monosiphonous 
except perhaps where fine corticating filaments clothe the 
base of the main axis; plants forming tufts attached by a 
system of rhizoidal filaments to rock surfaces or the thalli 
Or Other alsac 7 ie sae Bite sie vie wile Sie Sa 
Minute filamentous plants creeping within the tissues of animals 
or other algae; or forming crusts, discs, patches, hemispherical 
or brush-like tufts of small size (not more than a half inch long) 
on the thalli of other algae, on animals or on rock surfaces ... 3 
Filamentous thalli, monosiphonous only in early stages and at 
the tips of the branches. Cortication by longitudinal 
division of the original filaments which are not provided with 
an enlarged and conspicuous apical cell ue oe Bag CE 
