THE ALGAE OF BERMUDA. 



27 



FAMILY RIVULARIACEAE. 



CALOTHRIX Agardh. 



1. Heterocysts basal only. 



1. Heterocysts basal and intercalary. 



2. Trichomes violet. 



2. Trichomes olivaceous or aerugineous. 

 3. More or less endophytic. 

 3. Not endophytic. 



4. Filaments in stellate tufts on other algae. 



4. Filaments not in stellate tufts; saxicolous. 

 5. Trichomes olivaceous. 

 5. Trichomes aerugineous. 



6. Filaments attached at the middle. 



6. Filaments attached at one end. 

 7. Filaments 9-10 n diam. 

 7. Filaments 12-40 /j, diam. 



2. 

 6. 



C. fusco-violacea. 

 3. 



3. C. parasitica. 



4. 

 6. C. confervicola. 



5. 

 2. C. scopulorum. 



4. C. aeruginea. 

 7. C. pilosa. 



7. 



4. C. aeruginea. 

 5. C. Crustacea. 



1. C. FUSCO-VIOLACEA Crouan ex Bornet & Flahault, 1886, p. 352; 

 P. B.-A., No. 2060. On Enteromorpha, Ectocarpus etc., rock pool, 

 South Shore, Jan., Hervey. 



2. C. SCOPULORUM Agardh ex Bornet & Flahault, 1886, p. 353; 

 Bornet & Thuret, 1880, p. 159, PL XXXVIII; P. B.-A., No. 1856. 

 On flat rocks between tides, Causeway, Shelly Bay, etc., common. 



3. C. PARASITICA Thuret ex Bornet & Flahault, 1886, p. 357; 

 Bornet & Thuret 1880, p. 157, PL XXXVII, figs. 7-10. In Trichoghea 

 Herveyi, Cooper's Island, April, Collins ; in gelatinous mass of various 

 algae, in drip from Aquarium outlet, Aug., Collins. Occasionally 

 found in various loose-tissued algae. 



4. C. AERUGINEA Thuret ex Bornet & Flahault, 1886, p. 358; 

 Bornet & Thuret, 1880, p. 157, PL XXXVII, figs. 1-6. On rocks, 

 North Shore, mixed with Schizothrix etc., Nov., Hervey. 



5. C. CRUSTACEA Thuret ex Bornet & Flahault, 1886, p. 359; 

 Bornet & Thuret, 1876, p. 13, PL IV. Spanish Rock, April; on 

 Sargassum, Gravelly Bay, Dec., Hervey. 



6. C. CONFERVICOLA Agardh ex Bornet & Flahault, 1886, p. 349; 

 Bornet & Thuret, 1876, p. 8, PL III. On Cladophora crystaUina, 

 Harrington Sound, Collins. 



7. C. PILOSA Harvey ex Bornet & Flahault, 1886, p. 363; Harvey, 

 1858, p. 106, PL XLVIII. C. Common in shallow pools and on flat 

 rocks between tides. 



