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176 THE MARINE ALGÆ OF NEW ENGLAND. in a double row in terminal fusiform branches (stichidia); cystocarps terminal on the branches, ovate, with a distinct carpostome, spores pyriform, attached to short filaments which are given off from a basal placenta. A genus of about twenty species, characterized by their lurid purple color and by growing in places where the water is not very salt, some species, it is said, even growing in freshwater. They inhabit principally the tropics. The genus is intermediate between Polysiphonia and Dasya, and some species have been previously referred to Rhodomela. The tetraspores are in stichidia, as in Dasya, but the cystocarpic spores seem to us more nearly like those of Polysiphonia. The frond is originally monosiphonous, and soon becomes polysiphonous, the number of siphons not being as constant as in Polysiphonia. The corticating cells, when present, are regularly arranged in transverse bands. The development of the frond has been studied in detail by Dr. Ambronn in B. scorpioides. B. RIVULARIS, Harv., Ner. Am. Bor., Part II, Pl. 14 d. Exs.—Alg. Am. Bor., Farlow, Anderson & Baton, No. 54. Fronds an inch high, capillary, rising from a procumbent base, branches flexuous, bipinnate, pinnæ distichous, alternate, patent, loosely pinnulate, pinnules subulate, section of main branches showing about seven siphons; tetraspores cruciate, in two rows in oblong stichidia below the tips; cystocarps ovate, terminal on the shortened, naked, lower pinnæ. On submerged logs in patches. Hell Gate, N. Y., Harvey; Fort Lee, N. Y., Mr. Averill; College Point, Astoria, C. H. Peck; common southward; Australia. A common species from Charleston, S. C., southward, but only occasionally found with us. The only certain localities are near New York City, and it is extremely doubtful whether it was ever found in the arctic waters of the Isle of Shoals, where it was reported by Captain Pike. The species is small and rather insignificant, but is easily recognized by its polysiphonous structure and ramification. There are no cortications, and the species belongs to the subgenus Stictosiphonia. DASYA, Ag. (From δασυς [dasys], hairy.) Fronds bright red, filiform or compressed, distichously or irregularly branching, composed of a monosiphonous axis surrounded by several (4-12) siphons, often corticated with irregularly shaped cells, clothed in the upper part or throughout with colored, monosiphonous, dichotomous branchlets; antheridia in siliculose tufts on the branchlets; tetraspores tripartite, borne in regular rows in lanceolate or ovatelanceolate enlargements of the branchlets; cystocarps ovate, acuminate, sessile or pedicellate, spores terminal on branching filaments arising from a basal placenta. A large and beautiful genus, including about seventy species, of which the greater part
REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 177 are tropical, Australia being especially rich in species. The genus is divided into a number of subgenera, and is connected by Bostrychia and Tænioma with Polysiphonia. The tetraspores are in stichidia borne on the hair-like branchlets, while in Bostrychia they are in the polysiphonous branches, and in Tænioma the stichidia are formed from the flattened and scarcely altered branches. The cystocarps are borne on short lateral branches, which are usually slightly prolonged beyond the base of the cystocarp. The placenta of Dasya differs somewhat from that of Polysiphonia and our other genera of Rhodomeleæ. The spores are pyriform, but are borne on rather long branching filaments which surround the carpogenic cell at the base of the conceptacle, and which rise high up in its interior instead of being nearly sessile around the carpogenic cell, as in Polysiphonia. The development of the cystocarp has been studied in detail by Janczewski in D. coccinea. The fronds are either filamentous or more or less flattened, and, as in the case with most of the suborder, are formed from a monosiphous axis, from the cells of which whorls of filaments are given off, which in the older parts of the frond become parallel to the axis and replace the siphons of Polysiphonia. In most of the genus there are also secondary siphons and corticating cells, and either at the tip or throughout the frond tufts of delicate, dichotomous, monosiphonous branchlets, which are colored and not hyaline, as in the hairs of some other genera. D. ELEGANS, Ag., Sp. Alg. (Rhodonema elegans, Martens.—Dasya pedicellata, Ag., Syst.; Bailey, in Am. Journ. Sci., Vol. Ill, p. 84.)—Chenille. Pl. XV, Fig. 1. Exs.—Alg. Am. Bor., Farlow, Anderson & Eaton, No. 51. Fronds diœcious, villous, lake-red, six inches to three feet long, cylindrical, attached by a small disk, alternately 1-3 pinnate, with a percurrent axis, densely clothed throughout with tufts of purple, capillary, monosiphonous, dichotomous branchlets, sections of branches showing five cells around the axial cell; antheridia densely covering the lower cells of one of the divisions of the branchlets; tetraspores in two or three rows in linear-lanceolate or ovate pointed stichidia on the branchlets; cystocarps sessile on very short branches (pedicels) which are borne on the main branches. On Zostera, wharves, &c., below low-water mark. Common from Cape Cod southward; Adriatic Sea. A beautiful species, known to lady collectors by the name of chenille, at once recognized by its long, cylindrical, branching fronds, densely fringed with fine lake-colored filaments. It is found throughout the year. In drying it adheres closely to paper. The antheridia are much like those of Polysiphonia variegata, but are longer. The species extends to the West Indies, but appears to be more common in Long Island Sound than elsewhere. There is in the collection of the Peabody Academy of Salem a very large specimen, said to have been collected at Ipswich Beach, Mass., but the locality must be regarded as doubtful. At any rate, the species is quite unknown elsewhere north of Cape Cod. SUBORDER CORALLINEÆ, Decaisne. Fronds rose-colored or purple, calcareous, horizontally expanded or erect and branching, crustaceous, foliaceous, or filiform, continuous or S. Miss. 59——12
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