NOTES ON CYANOPHYCEiE. 47 



Dichothrix covipada (Ag.) B. & F. is not always readily to be 

 distinguished from D. gypsophila. It is snid to resemble Calothrix 

 parietlna in every way except that it hns the bninching of the 

 genus Dichothrix. It is sliorter than D. gypsophila, and has the 

 cells of the trichorae usually shorter, rather than longer, than 

 broad. A specimen from Samuel B. Parish, collected at San 

 Bernardino, seems to agree very well with the description of this 

 species. The sheaths are yellowish-brown, lamellose, more or less 

 dilated towards the summit, but, at the very summit, are usually 

 contracted again very suddenly. 



Mastigocoleus testarum Lagerh. does not seem to be at all plenti- 

 ful in shells along the Californian coast, nor do any other shell- 

 boring alga3 appear to be so common as such forms are along the 

 Atlantic Coast of New England. This species, however, has 

 occurred to the writer in small quantity, growing in the shells of 

 the Eastern Oyster near Bay Farm Island, Alameda Omnty, 

 California. 



Hapalosiphon laminosus (Kuetz.) Hansgirg is common in the 

 waters of the Arrowhead Hot Springs, near San Bernardino, in 

 company with other characteristic thermal algse. It does not seera 

 to differ in any essential respect from specimens from Carlsbad, 

 distributed in Wittrock and Nordstedt's Exsiccatae (Nos. 758 and 

 759). It seems to be the same as H. major Tilden, for, while the 

 measurements of that species are said to reach 11/ji, the writer has 

 been unable to find trichomes over 9/j. in his copy of the American 

 Algse (No.- 167) and also was able to find equally broad trichomes 

 in the specimens from Carlsbad. These were exceptionally broad 

 trichomes, however, in both cases, the general average being the 

 same in both and in perfect agreement with the figures given by 

 Bornet and Flahault. 



Siigonema hormoides (Kuetz.) B. & F. is readily told from the 

 forms of St. minutam (Ag.) Hatsall by the fact that it has, as a 

 rule, only a single row of cells even in the main filament, while the 

 latter species has from two to four cells in each articulation, yet 

 Wolle has distributed the former under No. 30 of his distribution 



