482 BULLETIN OF THE BUREAU OF FISHERIES. 
Order 3. Rhodymeniales Schmitz. 
Rhodymeninz, De Toni, 1900, p. 387. 
Carpogonial filaments and mother cells of the auxiliary cells occurring together in 
pairs, nearly always united into definite procarps, the auxiliary cells usually cut off only 
after fertilization. Gonimoblast arising from an auxiliary cell after the fertilized egg 
has fused with this by means of a short carpogonial process, attached to a basal pla- 
centa, cystocarps not completely immersed in the frond. 
KEY TO FAMILIES. 
a. Gonimoblast somewhat immersed in the thallus, filaments radiating from their point of 
attachment on a median, thickened placenta within the fruit-bearing cavity, peri- 
carp) thick; perforated at the apex’. . ic /.c/gcicecmws ccc ve mylene oplewinciom's oveisreim cites tiemeerepalere mfererersie b. 
b. Gonimoblast much branched, densely crowded and confluent, usually hemispherical- 
convex, carpospores borne at the apices of the branches singly or in chains; tetra- 
sporangia cruciately or zonately divided ....................-- 1. SPHAEROCOCCACE# (p. 482). 
bb. Gonimoblast divided into several lobes successively developed, nearly all cells of 
the lobes forming spores; tetrasporangia nearly always cruciately divided. 
Losey wistep tsp Geis. Tose sboseeprsergens -,tatctsiake om gcdsis de terres 2. RHODYMENIACE4 (p. 487). 
aa. Gonimoblast sessile in the thallus, formed within the fruit-bearing cavity, covered by 
the cortex of the thallus with a perforation at the apex... .. 22... ee eee eee eee teen aes c. 
c. Procarp situated in the median layer of the thallus, gonimoblast attached to the median 
thickened placenta, gonimolobes usually indistinctly formed, carpospores borne at 
the apices of the fertile branches eae or in chains; ree triangularly 
divided. . staaiea ae ..3. DELESSERIACE# (p. 493). 
aaa, Gonimoblast ee to ne faalien: ae means far a Pde or sae base, entirely 
external or somewhat inclosed by the cortex in various WayS.............ees cece eeeneeene d. 
d. Cystocarps attached to the thallus by means of a broad base or a short pedicel, gonimo- 
blast attached by a large fusion, central cell within a pericarp perforated at the 
apex, carpospores large, single in the apices of the fertile branches, less often in 
chains; tetrasporangia triangularly divided . : . 4. RHODOMELACEA (p. 496). 
dd. Cystocarps entirely external or inclosed by the ebrtex, asked iGeaiderale pericarp) or 
more or less loosely enwrapped by their own branches, gonimoblasts single or 
more often in pairs, usually divided into several lobes, carpospores formed from 
nearly every cell of the fertile branches; be ches Riayat or cruciately 
divided . Seapptast sind thence ontHoasinss « heolsmacc yes ene ..5. CERAMIACE4 (p. 509). 
Family 1. SPHAZROCOCCACEZ (Dumort) Schmitz. 
Thallus terete or flattened, dichotomously or laterally branched, structure cellular 
or cellular filamentous; tetrasporangia situated in the cortical layer, scattered over the 
surface of the thallus or in nematheciumlike portions, usually zonately, less often cruci- 
ately divided; antheridia variously formed; carpogonia usually numerous on the fertile 
portions of the thallus, apparently closely associated with the cells which, after fertili- 
zation, give rise to the auxiliary cells; cystocarps rather prominent, sometimes formed 
in special branches and then supported by a quasi short stalk, pericarp often thick, 
usually provided with an apical pore, often joined to the ‘“‘nucleus’’ by sterile strands, 
gonimoblast arising from the base of the fruit, richly branched, densely crowded and 
confluent, usually hemispherical-convex, forming spores singly or in chains at the apices 
of the fertile filaments. 
About 150 species in warm and temperate seas, especially in Australian regions. 
