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THE SEAWEEDS 
Family BONNEMAISONIACEAE Engler and Prantl 1897. 
Plants of moderate size, slenderly branched, with an evident axis and 
extensive branch systems; growth apical, an axial row of cells being sur- 
rounded by short, compact, branched cell rows constituting a pseudo- 
parenchymatous cortex with a continuous surface; sporangia unknown; 
spermatangia in dense masses covering small lateral branchlets ; carpogenic 
branches lateral on the corticating cell rows, forming after fertilzation a 
cystocarp with a definite pericarp, which is chiefly developed from adjacent 
tissue and which surrounds the gonimoblasts and associated nutritive cells. 
Bonnemaisonia C. Agardh. Asparagopsis Montagne. 
Probably Leptophyllis J. Agardh. Ptilonia J. Agardh. Delisea 
Lamouroux. 
Order GELIDIALES Kylin 1925. 
Plants with slender, wiry, redivided branches; corticated, ultimately 
developing the multiaxial type of structure'; assimilatory cells with lateral 
chromatophores ; asexual reproduction by tetraspores formed after meiosis 
in sporangia at or below the thallus surface ; sexual reproduction by sper- 
matia in spermatangia formed from the surface cells and carpogonia on 
carpogenic branches loosely associated with chains of nutritive cells; the 
carpogonium producing gonimoblast filaments, on which carposporangia are 
borne among the nutritive cells ; auxiliary cell lacking. 
Family GELIDIACEAE Kylin 1925. 
This is the only family in this order, and contains the genera Gelidium 
Lamouroux, and Pterocladia J. Agardh. 
Order CRYPTONEMIALES Oltmanns 1904. 
Plants showing various shapes from filiform to fleshy-membranous or 
rocklike ; corticated, with the multiaxial type or the central filament type 
of structure with an apical cell ; asexual reproduction by tetraspores formed 
after meiosis in sporangia at the thallus surface, or in sunken pits or con- 
ceptacles; sexual reproduction by spermatangia borne on surface cells or 
the lining of conceptacles and by carpogonia on carpogenic branches 
sunken in the cortex or in conceptacles; the carpogenic branches being 
associated with typical auxiliary axes which are neighbouring to the car- 
pogenic axes or more commonly remote; carpogonium after fertilization 
ordinarily producing ooblast filaments which transmit the diploid nuclei 
to the auxiliary cells, from which the carposporangium-bearing gonimoblast 
filaments are produced. 
Family DUMONTIACEAE (Bory) Schmitz 1889. 
Plants more or less branched, or plane and entire, soft; the original 
axial filament and apical growth soon obscured, the plants then appearing 
to have a pseudo-parenchymatous cortex and a filamentous, often hollow 
