412 BULLETIN OF THE BUREAU OF FISHERIES. 
KEY TO SPECIES. 
Trichomes 9 to 25 mic. in diameter, cells 2 to 4 mic. long; sheaths up to 5 mic. thick, color- 
less, later becoming lamellose; apex not tapering, no calyptra, transverse walls usually 
STANM Ate” spe ciatosjac ainjeleiein ecisis ois Gels «loin ag ams cae aeLRe yee eee teeter Lets Se Oze) Ged Ones) MEAT) a 
Trichomes 5 to 12 mic. in diameter, cells 2 to 3 mic. long; sheaths up to 3 mic. thick, colorless, 
lamellose with age; apex slightly tapering, furnished with calyptra, transverse walls fre- 
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Trichomes 2.5 to 6 mic. in diameter, cells 1.5 to 5.5 mic. long; sheaths thin, colorless, later 
becoming thick and lamellose; apex not tapering, furnished with calyptra, transverse walls 
usally not distinct vote deiejaeisies ep Vistas pirjss “bigmractiges “tat tose eedet is Eisele a eek TCAD Aga) 
1. Lyngbya confervoides Agardh, ex Gomont. 
Lyngbya confervoides, Agardh, 1824, p. 73. 
Lyngbya confervoides, Harvey, 1858, p. 103, pl. 47¢. 
Lyngbya nigrescens, Harvey, 1858, p. 102, pl. 47d. 
Lyngbya luteo-fusca, Farlow, 1882, p. 35 (excluding synonyms), 
Lyngbya confervoides, Gomont, 1892, tome 16, p. 136, pl. 3,£.3-6. 
Lyngbya confervoides, Forti, in De Toni, 1907, p. 271. 
Lyngbya confervoides, Tilden, 1910, p. 119, pl. 5, f. 39. 
A. A. B. Ex. No. 48 (L. luteo-fusca). 
P. B.-A. Nos. 255, 1106. 
Plant mass about 5 cm. in height, forming extensive mats or an intricate ragged mass, fasciculate, 
mucous; dull yellowish or dark green, sometimes violet when dry; filaments tangled, long, straight, 
somewhat rigid, ascending from a decumbent base; sheaths up to 5 mic. thick, colorless, later becoming 
lamellose and roughened on the surface; trichomes not attenuated at the apices, not constricted at the 
joints, 9 to 25 mic. in diameter, cells 2 to 4 mic. long, apical cell rotund, no calyptra; transverse walls 
usually granulated; cell contents olive or blue-green. 
Maine to Florida; Nebraska; West Indies; warm and temperate waters everywhere. 
Very abundant on rocks and shells along town front, especially on Duncan breakwater, very abun- 
dant on rocks of Fort Macon jetties, and less abundant on rocks of Shackleford jetty, Beaufort, N.C. 
Forms the uppermost zone of alge occurring up to the median high-tide line, sometimes mixed with 
minute specimens of Cladophora, Chetomorpha, and Enteromorpha, sometimes forming pure growths 
over large areas. April to October, probably throughout the year. This is the only species belong- 
ing to the Myxophycee that has been found at Beaufort in sufficient quantity to be conspicuous. 
2. Lyngbya semiplena (Agardh) J. Agardh, ex Gomont. 
Calothrix semiplena, Agardh, 1827, p. 634. 
Lyngbya semipiena, J. Agardh, 1842, p. 11. 
Lyngbya semiplena, Gomont, 1892, tome 16, p. 138, pl. 3, f. 7-11. 
Lyngbya semiplena, Forti, in De Toni, 1907, p. 273. 
Lyngbya semiplena, Tilden, 1910, p. 118, pl. 5, f. 38. 
P. B.-A. Nos. 5, 1059, 1452. 
Plant mass rarely beyond 3 cm. in height, forming extensive mats, mucous; usually dull yellowish 
or dark green, becoming dark violet when dry; filaments ascending from a decumbent tangled base, 
soft, flexuous; sheaths up to 3 mic. thick, colorless, somewhat mucous, lamellose with age; trichomes 
slightly attenuated at the apices, not constricted at the joints, 5 to 12 mic. in diameter, cells 2 to 3 mic. 
long, apical cell bearing a depressed conical or rotund calyptra, transverse walls frequently granulated. 
Maine to North Carolina, probably farther; Nebraska; Washington; California; Mexico; West 
Indies; Hawaii; Atlantic and Mediterranean shores of Europe. 
Very abundant, forming extensive mats almost covering posts of wharf and beacon between tide 
lines, mixed with other Myxophycee, Ocracoke, N. C. 
