THE ALGAE OF BERMUDA. 95 



Erythrocladia Rosenvinge. 



E. SUBIXTEGRA Rosenvinge, 1909, p. 73, figs. 13-14; Borgesen, 

 1915, p. 7, figs. 3-4; P. B.-A., No. 2086. On Bryopsis pennata, 

 Tucker's Town, April; on Caulcrpa cmssifolia, Hungry Bay, May, 

 Collins; on Cladophora cafcnifcra, Gravelly Bay, Feb., Hervey. 

 Probably common, but perceptible only on microscopic examination 

 when it appears in the form of minute orbicular disks, of closely set 

 radiating filaments, dichotomously branched, united laterally except 

 at the edge, closely adherent to the host. At Gibbet Island it grew 

 in company with Pringsheimia scufata, the fronds of which have much 

 the same structure; their bright green color contrasts strongly with 

 the red of the Erythrocladia. 



GoNiOTRiCHUM Kiitzing. 



1. Filaments one or at most two cells wide. 1. G. elegans. 



2. Main filaments many cells wide. 2. G. Humphrey!. 



1. G. ELEGANS (Chauv.) 'Le Johs, 1863, p. 103; Rosenvinge, 1909, 

 p. 75, fig. 15; Borgesen, 1915, p. 4, fig. 2. Bangia elegans Chauvin, 

 1842, p. 33. On many species of algae, especially on Codium and its 

 epiphytes, very frequently met with as isolated individuals, rarely 

 in large quantity. The filaments are often simple; when branched, 

 the branching approaches lateral rather then dichotomous; the cells 

 are 10-15 ^ diam., spherical or slightly compressed or elongate; they 

 are smallest at the base of the filament, largest near the apex, while 

 the filament is largest at the base, up to 25 /jl, tapering slightly towards 

 the apex. Lateral division of cells by an oblique wall is not uncom- 

 mon. It is quite distinct from the duplication by displacement 

 described by Rosenvinge, 1909, p. 75, and seems to be a normal process. 



2. G. HuMPHREYi Collins, 1901, p. 251; P. B.-A., No. 421; 

 Bangiopsis suhsimplex Borgesen, 1915, p. 10, figs. 5 and 6, not Comp- 

 sopogon suhsimplex Mont. Among other algae, Ectocarpus Mitchellae, 

 Calothrix fusco-violacea, Enteromorpha species, etc., forming a dense 

 growth on the bottom of a rock pool near Gravelly Bay, Jan., 

 Hervey. The fronds are more freely branched than in the material 

 from Jamaica, but the main stems are not as stout; otherwise they 

 are identical. 



