1918] Gardner: Xeir Pacific Coast Marine Algae III 467 



cellulis 2.5-3.5|Lt loiigis ; eytioplasraate dilute clialybeo, granulas leviter 

 angulatas, paiieas et late disseminatas praebente ; parietibus teniiibus, 

 distinetis; eellula termiuali niaxime convexa, membrana snperne uon 

 incrassata. 



Triehomes very loosely twisted into a more or less regular spiral, 

 and much knotted and contorted, 14.5-16;u, diani., comparatively short, 

 slightly torulose, not tapering at the apices; cells 2.5-3.5/i, long; pro- 

 toplast i)ale steel-blue, with few scattered, somewhat angular granules ; 

 cell walls thin, distinct, terminal cell very convex, outer wall not 

 thickened. 



Growing on rocks and among (Indopliora trivhotoma (Ag.) Kuetz. 

 in tide pools along high-tide level. Lands End, San Francisco, Cali- 

 foi'uia. Type no. 1634, Gardner. 



Arihrospira hreviarticulata is distinguished from all other species 

 of tlie genus by its much greater length, and greater diameter, by its 

 lieing looselv coiled, and bv its relativelv much shorter cells. 



Phormidium hormoides Setchell et Gardner sp. nov. 



Plate 40, fig. 23 



Strato indefinito tenui, expanso, gelatinoso; trichomatibus bre- 

 vibus, leviter flexuosis, moniliformibus, 2.4^2. 7/a diam. ; vaginis hya- 

 linis, amplis, gelatinosis, diffluentibus ; cellulis quadratis aut sub({uad- 

 ratis, maxime ad dissepimenta constrictis, eellula apicali majori, 

 subsphaerica, membrana superne non incrassata. 



Filaments forming a thin, exi:»anded, gelatinous stratum; triehomes 

 short, somewhat flexuose, moniliform, 2.-1— 2. 7/a diam. ; sheaths hyaline, 

 ample, gelatinous, confluent ; cells quadrate or sub(|uadrate, extremely 

 constricted at the dissepiments, terminal cell larger, subspherical, end 

 wall not thickened. 



Forming thin strata on glass aquaria of salt water from the Pacific 

 Ocean. Phvsiological Laboratory, LTniversity of California, Berkeley, 

 California,"! 905. Type no. 1535, Gardner." 



Phorniiiliuiit Itornundes is very closely related to 1'. fuiu olanoii 

 (Mont.) Gomont, which was found growing in small pits in calcareous 

 rock on the coast of France, and from which it differs in habitat, in 

 the size of the filament and in the shape of the terminal cell. The 

 filaments as viewed under the microscope are not uniformly distributed 

 in the stratum but seem to have a tendency to aggregate into fascicles 

 which anastomose freely, giving the stratum somewhat the appear- 

 ance of a very delicate net, although many short filaments crawl out 

 into the interstices. 



In the spceinicii collected Phormidium liorttundis is mixed with 

 another undetermined filamentous species of ^Myxophyceae, about 



