THE MAEINE ALG^ OF NEW ENGLAND. 177 



are tropical, Australia being especially rich in species. The genus is divided into a 

 number of subgenera, and is connected by Bostrychia and Tcenioma with Polysiphonia. 

 The tetraspores are in stichidia borne on the hair-like branchlets, while in Bostrychia 

 they are in the polysiphonous branches, and in Tamioma the stichidia are formed from 

 the flattened and scarcely altered branches. The cystocarps are borne on short lat- 

 eral 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 gen- 

 era of Bhodomelew. 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 carpo- 

 genic 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 monosiph- 

 onous 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 Poly- 

 siphonia. 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, monosiph- 

 onous branchlets, which are colored and not hyaline, as in the hairs of some other 

 genera. 



D. elegans, Ag., Sp. Alg. (Rhodonema elegans, Martens. — Dasya 

 pedicellate, Ag., Syst. ; Bailey, in Am. Journ. Sci., Vol. Ill, p. 84.) — Che- 

 nille. PI. XV, Fig. 1. 



Exs. — Alg. Am. Bor., Farlow, Anderson & Eaton, No. 51. 



Fronds dicecions, villous, lake-red, six inches to three feet long, cylin- 

 drical, attached by a small disk, alternately 1-3 pinnate, with a percur- 

 rent 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 branch- 

 lets ; 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 recog- 

 nized 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 CORALLINES, Decaisne. 



Fronds rose-colored or purple, calcareous, horizontally expanded or 

 erect and branching, crustaceous, foliaceous, or filiform, continuous or 

 S. Miss, 59 12 



