THE ALGAE OF BERMUDA. 21 



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

 North Shore, Aug., Collins. 



*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, 1S93, 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 n diam., usually over 7 /*. 3. 



2. Trichomes 4 M diam. or less, seldom over 3 /u. 5. 



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



o. Dissepiments granulate. 4. 



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



3. L. confervoides. 

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



4. L. semiplena. 

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



5. L. lutea. 

 5. Trichomes about 2 n 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 Leibleinia, 

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

 free. 



2. L. MAJUSCULA Harvey ex Gomont, 1893, p. 151, PL III, figs. 

 3-4; Harvey, 1858, p. 101, PI. XLVII. 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 



