Myxophyceae 209 



wood Pond. (Wolle). Pennsylvania. Bethlehem. (Wolle). Florida. 

 (WoUe). South Carolina. Strouds. August, October 1896. (Green). Ohio, 

 Plankton. Lake Erie, Put-in-Bay. (Snow). Minnesota. Forming large 



masses, dark, nearly black in color, on surface of stagnant lake. Long Lake, 

 Hennepin County. September 1895. (Shaver and Tilden). Central America. 

 Nicaragua. (Agardh). West Indies. In rapid current of stream. "Roar- 

 ing River,'' St. Ann's, Jamaica. March 1893. (Humphrey). Morant Bay. 

 August 1894. (Pease and Butler). 



384. Plectonema terebrans Bornet and Flahault. Sur quelques Plantes 



vivant dans le Test Calcaire des Mollusques. Bull. Soc. Bot. de 



France. 36: CLXIII. pi. 10. f. s, 6. 1889. Gomont. Monogr. Oscill. 



123. 1893. De Toni. Syll. Algar. 5: 497. 1907. 



Collins. Some Perforating and other Algae on Fresh-Water Shells. 



Erythea. 5: 95. 1897. Collins, Holden and Setchell. Phyc. Bor.-Am. Fasc. 



7. no. 306. 1897. Collins. Preliminary Lists of New England Plants. — V. 



Marine Algae. Rhodora. 2: 42. 1900; Phycological Notes of the late Isaac 



Holden. — II. Rhodora. 7: 223. 1905. Collins, Holden and Setchell. Phyc. 



Bor.-Am. Fasc. 28. no. 1357. 1907. 



Plate XL fig. 6. 



Filaments slender, elongate, flexuous, branched; false branches often 

 solitary; sheaths very thin, colorless, cylindrical; trichomes .9-1. S mic. in 

 diameter, not constricted at joints; cells 2-6 mic. in length; apical cell ro- 

 tund; transverse walls marked by two refringent granules; cell contents 

 pale blue-green. 



Maine. In live shells of L i 1 1 o r i n a, in company with H y e 1 1 a 

 caeSpitosa. Cape Rosier. July 1901. (Collins). Rhode Island. (Col- 

 lins). Connecticut. In Unio shells. Twin Lakes', Salisbury, Litchfield 

 County. August 1895. (Setchell and Holden). "Very abundant all through 

 the shells, and when the latter were decalcified, formed a dense mat 

 which made it rather difficult to distinguish the other algae that grew in 

 company with it." — Collins. In marine shells with other algae. Harbor. 

 September, October. (Holden). 



585. Plectonema nostocorum Bornet in Bornet and Thuret. Notes Algolo- 

 giques. 2: 137. 1880. Gomont. Monogr. Oscill. 122. pi. i. f. 11. 1893. 

 De Toni. Syll. Algar. 5: 495. 1907. 



Collins. Notes on Algae. — III. Rhodora. 3: 133. 1901; The Algae of 

 Jamaica. Proc. Am. Acad. Arts Sci. 37: 240. 1901; Algae of the Flume. 

 Rhodora. 6: 230. 1904. Collins, Holden and Setchell. Phyc. Bor.-Am. 

 Fasc. 24. no. 1164. 1904. Lemmermann. Algenfl. Sandwich. -Inseln. Bot. 

 Jahrb. 34: 624. 1905. 



Plate XL fig. 7. 



Filaments graceful, elongate, somewhat straight, at first much branched, 

 later sparingly branched; false branches solitary or in pairs; sheaths color- 

 less, very thin, cylindrical; trichomes 1-1.5 mic. in diameter, constricted at 



