THE ALGAE OF BERMUDA. 21 



No. 2056. Forming a pinkish film over rocks between tide marks, 

 North Shore, Aug., CoIHns. 



*3. P. VALDERiANUM Gomont, 1893, p. 187, PI. IV, fig. 20; P. B.-A., 

 No. 2157. Among other algae in a blackish coating on rocks and 

 on Bostrychia, Aug. In thick wrinkled sheets on brackish water, 

 near old race course Dec. Collins. 



*4. P. Retzii Gomont, 1893, p. 195, PI. V, figs. 6-9; P. B.-A., 

 No. 2057. Forming a light green, firm coating on rock between tide 

 marks. North Shore, Sept., Collins. 



Lyngbya Agardh. 



1. Filaments attached at the middle. 1. L. Meneghiniana. 



1 . Filaments attached at one end or free. 2. 



2. Trichomes over 5 m diam., usually over 7 y,. 3. 



2. Trichomes 4 ^ diam. or less, seldom over 3 n. 5. 



3. Trichomes 16-60 n diam., dissepiments not granulate. 2. L. majuscula. 



3. Dissepiments granulate. 4. 



4. Trichomes 9-25 y. diam., apex not attenuate nor capitate. 



3. L. confervoides. 

 4. Trichomes 5-12 y. diam., apex usually attenuate and capitate. 



4. L. semiplena. 

 5. Trichomes 2.5-4 n diam., straight or flexuous, not regularly spiral. 



5. L. lutea. 

 5. Trichomes about 2 y diam., more or less spiral. 6. L. Lagerheimii. 



1. L. Meneghiniana Gomont, 1893, p. 145. Mangrove Creek, 

 Farlow; on Codium, Cooper's Island, Collins; Gibbet Island, March, 

 Hervey. The only representative here of the subgenus Leihleinia, 

 the filaments bent hairpin-shape, attached in the middle, both ends 

 free. 



2. L. MAJUSCULA Harvey ex Gomont, 1893, p. 151, PI. Ill, figs. 

 3-4; Harvey, 1858, p. 101, PI. XL VII. A; P. B.-A., No. 2001. Rein; 

 Moseley; Walsingham Grotto, March, Alden Fish pond, Dec, Hervey. 

 Usually blackish green, occasionally reddish or violet. 



3. L. CONFERVOIDES Agardh ex Gomont, 1893, p. 156, PI. Ill, 

 figs. 5-6; including forma violacea Collins, P. B.-A., No. 1853. Com- 

 mon in floating masses in quiet waters, as attached tufts in more 

 exposed places, nearly everywhere. A brownish or yellowish green 

 is the more usual color, but violet and reddish shades are not uncom- 

 mon. These are in striking contrast to the normal color, but from 

 our observations on the species of Lyngbya found at Bermuda, we are 



