110 
2. Dictyosiphon, Grev.—D. foeniculaceus, Grev. On stones in 
pools, and on other Algw. Thimble Islands, Mrs. Davis. 
3. Punctaria, Grev.—P. latifolia, Grev. Not very common. 
Orper V.—CHORDARIACEA. 
1. Chordaria, Ag.—Ch. flagelliformis, Ag. On rocks and 
stones and upon Algw.—Ch. divaricata, Ag. Parasitic on small 
Alge, and on stones. 
2. Leathesia, S. F. Grav.—Z. tuheriformis, S. F. Gray. Rare. 
3. Elachista, Duby.—Z. fucicola, Fries. Parasitic on the Fuci. 
Orper VL—ECTOCARPACEA. 
1. Sphacelaria, Lyugb.—S. cirrhosa, Ag. Thimble Islands, &c. 
2. Ectocarpus, Lyngb.—Several species of this genus have been 
collected, but not, as yet, satistactorily determined : however, they 
will probably comprise Z. firmus, Ag. (&. littoralis, Harv , in Ner. 
Am. Bor.); E. siliculusus, Lyngb. ; E. viridis, Harv., &e. 
Suscrass I]. RHODOSPERMEAL, 
wi Orprr L—RHODOMEKACEZ. | 
1. Chondria, Ag.— Cn. dasyphylla, Az. On other Alga, &.— 
Ch. Baileyana, Mont. (C. striolata, Ag.) On Alge, &e.—Ch. 
,\tenuissima, Ag. On Alga, stones, &e. 
i\ 2. Rhodomdla, Ag.—/?. subfusca, Ag. On rocks and stones ; 
rather rare; and var. Rochei (R. Rochei, Harv., in Ner. Am. Bor.) 
On Alge and stones. 
3. Polysiphonia, Grev.—P. wrceolata, Grev., and var. formosa. 
On rocks.—P. Olneyi, Harv. On Zostera marina, &¢.—P. Harveyi, 
Bail. Parasitic mostly upon Zostera.—P. violacea, Grev. On Zos- 
tera, &c. Falkner’s L, and Thimble Is.—P. variegata, Ag. On 
Zostera, stones, &c.—P. nigrescens, Grev. On shells, stones, &c.— 
P. fastigiata, Grev, Parasitic on the Muci ; not common 
4. Dasya, Ag.—D. elegans, Ag. On Alga, rocks, &c., mostiy. 
in deep water: thrown up on the shore. (An elegant Alga, appro- 
priately named. ) 
Orper IJ.—LAURENCIACEA. 
Champia, Desv.— CA. parvulz, Harv. On Alga, shells, &c. 
Orper III.—CORALLINACEA. 
1. Corallina, L—C. officinalis, L. On stones, shells, &c. 
Prot: D. C. Eaton. 
2. Melobesia, Lmx.—_M. membranacea, Lmx. On Zostera ma- 
rina. Prof. D. C. Haton.—M. pustuiata, Lmx. On Fuci. Prof. 
D. C. Eaton. 
3. Lithothamnion, Phil.—Z. polymorphum, Lmx. 
Orper IV.—SPHEROCOCCOIDEA. 
1. Grinnellia, Harv.— @. Americana, Harv. On stones, shells, 
sponges, &c., in deep water; cast ashore. 
2. Delesseria, Lmx.—D. sinwost, Lmx. Thimble Is, Mrs. 
Davis. Light House Point. Prof. Eaton, F. W. Hall, and A. 
H. Young. : 
