THE ALGAE OF BERMUDA. 25 



NosTOC Vaucher. 



*N. COMMUNE Vaucher ex Bornet & Flahault, 1888, p. 203; P. B.-A., 

 No. 1901 ; N. ciniflonum Bornet & Thuret, 1880, p. 102, PI. XXVIII, 

 fig. 13. Common everjov-here, especially on sandy soil; thin brittle 

 skins in dry weather, expanded thickish soft masses in wet weather. 

 No spores seen. Native name, " Devil's Tobacco." 



Family SCYTONEMACEAE Kiitzing. 

 MiCROCH.\ETE Thuret. 



M. viTiENSis Askenasy ex Bornet & Flahault, 1887, p. 85. Scat- 

 tered filaments on Wrangelia penicillata, Harris Bay, Jan., Hervey. 



ScYTONEMA Agardh. 



1. Sheaths not lamellate. 2. 



1. Sheaths lamellate. 3. 



2. Trichomes 5-7 M diam. 1. S. varium. 



2. Trichomes 6-14 fi diam. 2. S. ocellatum. 



3. Branches usually geminate, free and divergent. 4. 



3. Branches frequently sohtary, adherent at base. 5. S. crustaceum. 



4. Filaments 15-21 ;u diam.; sheath thin at apex. 3. S. figuratum. 



4. FUaments 18-36 M diam.; sheath thick throughout. 4. S. myochrous. 



*1. S. VARiimi Kiitzing ex Bornet & Flahault, 1887, p. 97; Kiitzing, 

 1850-52, p. 6, PI. XXIII, fig. II. High up on walls of a cave at Wal- 

 singham; shore of pool near Walsingham, April, Collins. 



*2. S. OCELLATUM Lyngbye ex Bornet & Flahault, 1887, p. 95; 

 P. B.-A., No. 711, on dunes, Paget, Farlow. 



*3. S. FIGURATUIM Agardh ex Bornet & Flahault, 1887, p. 101; 

 S. thermale Kiitzing, 1850-52, p. 5, PI. XVIII, fig. III. High up on 

 wall of cave near Walsingham, April, Collins. 



Bornet, 1889a, p. 155, shows that Conferva mirabiUs Dillwyn, 1807, 

 PI. XCVI, is identical with Scytonema figuratum of Agardh, and of 

 earlier date, and therefore changes the name to S. mirahile (Dillw.) 

 Bornet. But as the starting point for nomenclature of the hetero- 

 cysted Nostochaceae is definitely fixed at the Bornet & Flahault 

 monograph, it appears as if the later name by Bornet cannot be sub- 

 stituted. 



