THE ALGAE OF BERMUDA. 135 



1. G. TENUIS Agardh, 1828, p. 131; P. B.-A., No. 1895; Plate VI, 

 figs. 38-39; G. tlnjrsigera Askenasy, 1888, p. 36, PI. IX, figs. 1 & 4; 

 Vickers, 1905, p. 64; Callithamnion tenue, Harvey, 1858, p. 130. 

 Inlet, above and below Flatts Bridge, Jan., Feb., March, April, Dec., 

 Heron Bay, Jan., Hervey. Common at these stations in late winter 

 and early spring; cystocarps, antheridia and tetraspores all produced 

 from January to March. The similarity between Griffithsia tcnuis Ag. 

 and Callithamnion thyrsigera Thwaites has been noticed more than 

 once. Harvey, 1858, p. 130, kept up the distinction with some doubt. 

 Grunow, 1874, p. 8, considers the latter merely a robust form of the 

 former. Harvey had compared the plant from Beesley's Point, 

 New Jersey, with an authentic Mediterranean specimen; we have 

 compared with a Beesley's Point specimen of the original collecting 

 specimens from Atlantic City, N. J. (S. R. Morse), Nantucket (L. 

 L. Dame), Falmouth, Massachusetts (Collins), and G. thyrsigera, 

 Vickers, Algues de la Barbade, No. 182. All agree in essential details 

 with each other, and with the figures and text of Askenasy. The 

 Bermuda material seems to be more luxuriant, especially the tetra- 

 sporic; it is not uncommon to find 15 tetrasporangia in a whorl, five 

 whorls of tetrasporangia, mature or nearly mature, and two whorls of 

 immature, at once on an axis. Antheridia are borne on a pedicel of 

 one to three cells; Askenasy reports one-celled pedicels only. The 

 cystocarps were unknown until found on our Bermuda material ; they 

 are characteristic of Griffithsia, and the generic position of the species 

 may now be regarded settled. Rhizoids were frequent on the older 

 plants, of the usual form, unicellular, longer or shorter as required to 

 reach the substratum, where an expanded disk was formed. They 

 have thicker walls than the filament cells, and contain nearly as deeply 

 colored chromatophores. 



2. G. SCHOUSBOEI Montagne in Webb, 1839, p. 1 1, PI. X. Washed 

 ashore, St. George's, Feb., sand covered rock, Pink Bay, March, 

 Hervey. Agrees with the European plant in vegetative characters, 

 but in the absence of fruit the identification is only provisional. 



3. G. MONILIS Harvey, 1855, p. 559; in Hooker & Harvey, 1855- 

 1860, p. 332, PI. CXCV. B. In cave, Gravelly Bay, Dec., Jan., 

 March, on sand-covered rocks, Smith's Bay, March, Hervey; 

 Bethel's Island, Dec., Collins. Tetraspores in Jan. G. monilis is 

 an Australian species, and its occurrence here is of interest. Agardh 

 calls attention to its similarity to G. Schousboei, but while what we 

 take for that species occurs in Bermuda, it has most of the cells 

 cylindrical, a few ovoid, while in G. monilis the cells are strictly 

 globose, or a little elongated or depressed. 



