MARINE ALG OF BEAUFORT, N. C. 489 
Genus 3. Chrysymenia J. Agardh. 
Chrysymenia, J. Agardh, 1842, p. 105. 
Frond terete or somewhat flattened, hollow in parts or throughout the entire length, 
sometimes segmented by constrictions, variously branched, sometimes caulescent and 
almost solid below with hollow, vesicular, bladderlike lateral branches above; filled with 
loose jelly; structure cellular, central axis lacking, inner cells large, outer ones smaller, 
cortical ones minute, scattered filaments sometimes traversing the internal tube; tetra- 
sporangia scattered over the thallus surface, embedded among the cortical cells, cru- 
Fig. 31.—Meristotheca duchassaingii, showing tetrasporangia Fig. 34.—Chrysymenia agardhii, cross section of thallus, 
and internal structure (diagrammatic) X 30. X 183. 
Fig. 32.—Meristotheca duchassaingti, showing internal struc Fig. 35.—Nitophyllum medium (type), surface view show- 
ture and tetrasporangium, 183. ing veins and cells, X 33. 
Fig. 33.—Agardhinula brownee, structure of thallus and 
cystocarp, X 3o. 
ciately divided; cystocarps scattered over the frond, fairly conspicuous, hemispherical, 
opening by an apical pore, fruiting cavity with a trace of a filamentous network or 
entirely lacking this, gonimoblast arising from the base of the cavity, composed of several 
coalescent lobes, bearing many rotund carpospores irregularly grouped in masses, 
somewhat inclosed by a gelatinous covering. 
Fifteen to twenty species in warm seas. Some of the species of this genus resemble 
in external appearance species of Halymenia, from which they may usually be distin- 
guished by their structure. In the species of Chrysymenia the frond is hollow or nearly 
so, the wall consisting of one or two loose layers of large cells surrounded by one or two 
layers of small cortical cells; there are usually no filaments traversing the cavity. In 
