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118 THE MARINE ALGÆ OF NEW ENGLAND. A small genus, containing at the most only four or five species, of which S. furcellata is widely distributed. The genus is unmistakable on microscopic examination by the slender axis and large colorless cylindrical cells which cover the surface of the fronds, and by the peculiar cystocarps which are visible to the naked eye as dark red grains just under the surface. The species should be studied from living or alcoholic specimens, since, owing to the delicate substance, pressed specimens are badly distorted. S. FURCELLATA, Bivona. (Ginannia furcellata, Mont.; Phyc. Brit., Pl. 69.—S. furcellata, Notes Algologiques, Pl. 6.) Fronds solitary or clustered, cylindrical, rising from a disk-like base, several times dichotomous, divisions regular, apices obtuse. On stones and shells in five to ten fathoms. Newport, R. I., Bailey; Gay Head, Mass., W. G. F. A rare species with us, but widely distributed throughout the world, being found in most warm seas. In size and regularity of its dichotomous branching it resembles Polyides rotundas, but is much more delicate in substance and brighter colored. With us it is only known at a considerable depth and in rather cold waters, but in the Mediterranean it is frequent in warm shallow waters. It is not uncommon on shells of Mytilus near the Devil’s Bridge, Vineyard Sound, Mass., and is found washed ashore in the neighboring beach of Gay Head. The Californian form of what is supposed to be the same species is much more robust, and the var. undulaa, [sic] which Montagne considered a distinctspecies [sic], is somewhat compresed [sic] and constricted at intervals. When pressed the specimens are quite flat and the axis is plainly seen, giving the appearance of a membranous frond with a midrib. SUBORDER SPERMOTHAMNIEÆ. Fronds filamentous, monosiphonous, branching; antheridia tufted; cystocarps involucrate, spores borne free on the surface of a lobulated mass produced by the carpogenic cells. In this suborder we would place Spermothamnion and Bornetia, separated from Callithamnion and Griffithsia, respectively, in consequence of the spores being borne free. SPERMOTHAMNION, Aresch. (From σπερµα [sperma], a seed, and θαµνιον [thamnion], a small bush.) Fronds tufted, composed of procumbent monosiphonous filaments attached to the substratum by disk-shaped cells and vertical branching filaments; antheridia sessile on the inner side of the branches, composed of oval or cylindrical masses of small cells; cystocarps terminal on the branches, surrounded by an involucre of short incurved branchlets, spores free from one another and not surrounded by a gelatinous envelope; tetraspores tripartite, single or aggregated, borne on the inner side of the branchlets. A small genus, comprising, as far as known, less than half a dozen species, separated from Callithamnion because the spores at maturity are borne free on the surface of a lobulated mass which arises from the development of the carpogenic cells, and not, as
REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 119 in Callithamnion, held together by a gelatinous envelope. The trichophoric apparatus and the early stages of the development of the cystocarps, however, scarcely differ in the two genera. The species of Spermothamnion have been considered related to Wrangelia, but if we are to regard W. penicillata as the type of the last-named genus, as has been done by Thuret and Bornet in Notes Algologiques, the resemblance is not close. In spite of the fact that the fruit of Spermothamnion is not a true favella, there is little doubt that the genus should be placed in the Ceramieæ, near Callithamnion. The development of the genus has been very thoroughly studied and has formed the subject of several admirable papers, among which maybe mentioned Pringsheim’s account of S. roseolum, in his Beiträge zur Morphologie der Meeres-Algen; Nægeli on S. Turneri and hermaphroditum, in Beiträge zur Morphologie und Systematik der Ceramiaceæ; and Thuret and Bornet on Spermothamnion flabellatum, in Notes Algologiques. S. TURNERI, Aresch. (Callithamnion Turneri, Ag.; Phyc. Brit., Pl. 179; Ner. Am. Bor., Part III, p. 241.—S. roseolum, Pringsh., l. c.?—Herpothamnion Turneri, Næg.) Fronds forming densely matted tufts, procumbent filaments branching, attached by disk-like cells, vertical filaments one to three inches high, simple or slightly branching, naked below, pinnate above with opposite or sometimes alternate spreading pinnate branches, ultimate branches long and slender, often ending in a hair; antheridia ovate or cylindrical, sessile on the upper side of the branches; cystocarps involucrate, terminal on the branches; tetraspores tripartite, borne on the upper side of the ramuli, either solitary and pedicellate or clustered and sessile on short fastigiate branches. Var. VARIABILE, Harv. Branches and branchlets alternate or secund. In very dense tufts on algæ at low-water mark or in deep water. Common in Long Island Sound; var. variabile, Boston, Dr. Durkee. A species which is often found washed ashore in dense globose tufts from our southern limit to Nantucket. At the latter locality it is often found in very large quantities washed from deep water by the surf on Siasconsett Beach. The filaments are delicate and of a pleasant lake color. North of Cape Cod the species is hardly known with certainty. Specimens collected at Noank, Conn., have both tetraspores and young cystocarps on the same individual, but we have never seen antheridia on American specimens. Our plant seems to be the same as that figured by Pringsheim under the name of S. roseolum, and also corresponds closely to the species of that name in Algæ Scandinavicæ, No. 83. It appears without doubt to be the C. Turneri of the Phycologia Britannica and the Nereis, but we are unable to say whether it is the true C. roseolum of Agardh. SUBORDER CERAMIEÆ. Fronds filamentous or compressed, either monosiphonous or with a more or less corticated monosiphonous axis; antheridia in sessile tufts or patches or in a series of whorls; cystocarps (favellæ) composed of spores arranged without order and surrounded by a gelatinous envelope, naked or involucrate.
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