496 BULLETIN OF THE BUREAU OF FISHERIES. 
Frond flat, thin-membranaceous, 1 to 11 cm. wide, 6 to 45 cm. long, usually unbranched, supported 
on a short stalk continuous with the midrib, tapering at each end; tetrasporangial sori appearing as 
minute dots scattered over the surface, antheridia as small, whitish spots scattered over the frond, 
cystocarps as evident dots larger and more conspicuous than the tetrasporangial ones; tetrasporangia, 
_ antheridia, and cystocarps borne on different plants; color light to dark rosy pink, sometimes purplish. 
New England to West Indies. 
Fairly abundant throughout harbor and on jetties, Beaufort, N.C., 10 to 30 cm. below low water, 
December to May, small specimens occasional on Fort Macon jetties during summer and autumn, small 
specimens on coral reef ofishore, May, 1907, and August, 1914; few specimens 1 cm. tall or less, in 
sound, Pawleys Island near Georgetown, S. C., August, 1909. 
Family 4. RHODOMELACEZ& (Reichenbach) Harvey. 
Frond terete or flattened, usually richly laterally or dichotomously branched, erect 
or horizontal, structure usually radial, sometimes dorsiventral, cellular, sometimes 
cellular-filamentous, usually with a conspicuously polysiphonous axis composed of a 
segmented central axis surrounded by one or more circles of large pericentral cells of 
equal length, sometimes covered by one or more layers of small cortical cells, apical cell 
segmented transversely or obliquely (in one subfamily, Laurencie, approaching the 
tetrahedral type) the thallus bearing more or less numerous, persistent or evanescent, 
usually much branched, monosiphonous filamentous lateral outgrowths (trichoblasts) ; 
tetrasporangia numerous, arising from pericentral cells, embedded in the thallus, covered 
by special cover cells, scattered over the unaltered smaller branches or in altered branches 
(stichidia), triangularly divided; antheridia borne on trichoblasts, sometimes apparently 
on a polysiphonous branch, occurring as small compact bodies of various forms, oval to 
long cylindrical, terete or flattened, bearing a layer of spermatangia over all or nearly 
all the surface; carpogonia situated on trichoblasts, sometimes apparently on a poly- 
siphonous branch, closely associated with cells which, after fertilization, produce the 
auxiliary cells, forming definite procarps sooner or later inclosed by sterile outgrowths 
from the thallus; cystocarps external, conspicuous, secondarily situated on polysiphonous 
branches, sessile or borne on short stalks, oval or urceolate, pericarp thick, opening by 
an apical pore, gonimoblast arising from the basal placenta, consisting of a compressed, 
more or less compact tuft of richly branched filaments, whose apical cells usually produce 
single, large, oval, or club-shaped carpospores, but in one subfamily, Dasyee, form small 
cylindrical carpospores in short chains, the spores, in the former case, having the appear- 
ance of arising singly on short stalks from the base. 
The largest family of the Rhodophycee, containing about 600 species, occurring in 
all seas, especially in the temperate regions of the Southern Hemisphere. 
KEY TO GENERA. 
a. Growth of thallus sympodial, structure radial, with five pericentral cells, tetrasporangia 
not completely embedded in the stichidia, branching radial.................. 7. Dasya (p. a 
aa.. Growth of thallus monopodial o.oo... 2c. a. sete tet. AP MU Gd FIRE MIGREDCS eth ume kde. PE Rete are. « b. 
b. Thallus with dorsiventral structure, creeping, bearing elongated, alternate, lateral, 
creeping branches at regular intervals, and short, erect branches between these, 
tetrasporangia occurring singly......... ASR ..6. Herposiphonia (p. 507). 
6b. Thallus usually with radial sincere: eee en oulaaite or ath Sapte erect 
branches from an inconspicuous creeping base. ...... 6.66.65. 0 eee eee beeen es Cc. 
c. Polysiphonous axis not evident, thallus composed of large cells not arranged in 
circles, apical cell divided somewhat tetrahedrally, tetrasporangia situated with- 
out apparent relation to a pericentral cell................2 0. see eeeeee 1. Laurencia (p. 497). 
