vol.i] Setchell— Gardner. — Algce of Northwestern America. 179 



Family CHROOOOCCACE^. 



Chroococcus rufescens (Brebisson) Naegeli. 



Forming with Stigonerna a reddish coating on a rock five 

 hundred feet above sea level. Prince William Sound, Alaska, 

 Saunders (1901, p. 396). 



Chroococcus turgidus (Kuetzing) Nsegeli. 



Among other algae in pools of fresh water or on dripping 

 rocks. Glacier Valley, Unalaska, Alaska, A.A.L., No. 5023a! ; 

 •Juneau, Alaska, Saunders (1901, p, 396); in brackish water, 

 Whidbey Island, Wash., N.L.G., No. 472! 



Gloeocapsa ambigua f. fuscolutea Nsegeli. 



Among other alga?, especially Dichothrix Baueriana (Grunow) 

 B. & F. and Schizothrix Braunii Gomont, in a mountain stream. 

 Orca. Alaska, W. L. Jepson, No. 5175! 



The cell walls of this form are thick, opaque and reddish or 

 yellowish brown. 



Gloeocapsa ambigua f. violacea Nsegeli. 



Intermingled with the last. 



The only difference between this form and the last is in the 

 color of the cell walls which are distinctly violet and somewhat 

 more opaque. 



Gloeocapsa atrata Kuetzing. 



Intermingled with the last two. 



The present species differs from the last two in having the 

 walls transparent and either colorless or else very light blue. 

 They all seem to be forms of one species which is variable in this 

 respect . 



Gloeocapsa polydermatica Kuetzing. 



With other Cyanophyceas, forming a yellowish firm jelly on 

 dripping rocks. Near Iliuliuk, Unalaska, Alaska W.A.S. and 

 A.A.L., No. 4031! 



The specimens referred here have bhie green cell contents 

 and colorless stratified walls. The families are one or two-celled. 

 The cells measure 21-22 h- in diameter. 



