1917] Gardner: New Pacific Coast Marine Algae I 379 



p. 287) retains it as such but also retains Moebius' Spirocoleus as a 

 convenient subgenus or section of the genus Lynghya, into which he 

 assembles, along with L. Lagerheimii, six other species of small 

 dimensions, all of which are more or less spirally twisted. Arthro- 

 spira maxima is not much unlike Lynghya spirulinoides Gomont, 

 differing generically in the absence of a sheath. However, the sheath 

 of L. spirulinoides is said to be inconspicuous. In another instance 

 Forti (1907, p. 207) has retained Rabenhorst's form vaginata with 

 "fills subdistincte vaginatis" as belonging to the genus Arthrospira. 



Spirulina Turp. emend. 



Trichomata multieellaria, cylindrica, evaginata, laxe aut dense 

 spiralia spiram laxam aut clausam efficientia; trichomatis apex vulgo 

 aequalis, ellula apicalis rotundata, calyptra nulla ; endochroma homo- 

 genea aut cum granulis instructa. 



Trichomes multicellular, cylindrical, evaginate, loosely or tightly 

 coiled into a more or less regular spiral ; apex of trichome usually not 

 tapering ; terminal cell rounded, without calyptra ; cell contents homo- 

 geneous or granular. 



Chlorochytrium Porphyrae Setchell et Gardner sp. nov. 



I'late 32, fig. 6 



Viride; cellulis sphericis, 40-60/x diam., in gelina exteriori hos- 

 pitis sub superficies geminas positis; chlorophoris singulis, primo 

 parvis demum per plures ramos radiantes emittentes augescentibus 

 et fine parietem cellularum tegentibus; pyrenoide singulo, magno, 

 in chlorophora ad partem superiorem cellulae posito ; parietibus cellu- 

 larum 2-3ju, diam., hyalinis, non laminatis; propagatione sexuali a 

 gametibus biciliatis, 3-4/i, diam., fusiformibus aut fere sphericis, per 

 foramen ovatum in pariete externo (gametangii) evadentibus; propa- 

 gatione asexuali a zoosporis aut a akinetibus ignota. 



Cells spherical, 40-GO/x diam., embedded within the host on both 

 sides; chromatophore single, at first small, covering the upper part 

 of the young plant, then increasing in size by sending out several 

 radiating arms and finally covering the cell wall ; pyrenoid single, 

 large, embedded within the clirouuitophore toward tlie upper part 

 of the cell ; cell wall 2-3/x diam., hyaline, not laminated ; color grass- 

 green; sexual reproduction b}' biciliate gametes, 3-4^ diam., fusiform 

 to almost spherical, escaping through the oval opening in the outer 

 wall ; asexual reproduction by zoospores aiul by akinetes unknown. 



Growing completely embedded witliin llie outer membrane of 

 Porphyra perforata f. segregata Setclicll and Tins, Lands End, San 

 Francisco, California. April, 1916. 



While collecting algae in the above-mentioned locality, I noticed 

 groups of plants of Porphyra on rocks near high-tide limit which 

 were considerablv dwarfed and almost as green as the small Ulva 



