66 West-Coast Porphyras. [ZOE 
Habitat. _P. Nereocystis is found attached to the stipes of 
Nereocystis Liitkeana in 3-5 fathoms of water. 
Distribution: From Alaska southward to Middle ealornia 
(57° 30'-36° 45’-N. lat.). 
Localities. St. Paul, Kadiak Isl., Alaska, W. 4. Setchell and 
A.A. Lawson! No. 5149; Gouaacilig Washington, WV. Z. Gara- 
ner/; Bolinas Bay, Marin Co., Calif., WA. Setchell! No. P2755 
Monterey Bay, Calif., W..A. Setchell! No. 3005a; C. L.. Ander- 
son! 
PoRPHYRA NaIADUM And. Zor, Vol. III, p. 148, 1892. 
This plant may readily be distinguished from all other species. 
of Porphyra by its base. While the structure of the base of all ’ 
Pacific Coast species examined, agrees with that so admirably 
described by Bornet and Thuret (’78) for ?. laciniata, the base of 
P. naiadum possesses a structure altogether different. 
P. naiadum is found growing on eel-grass, either on Ph sMospa- 
dix in exposed places i in the sublitoral zone or on. Zostera, shel. 
tered, in lagoons. When, during the winter months, we examine 
the blades of Phyllospadix, we, find here and there, small, reddish- 
brown, cushion- “shaped growths, which to the superficial gaze. 
appear like colonies of diatoms. Continued observation shows a 
gradual increase in the number of wartlike, more or less flattened 
structures. Finally they cover the blades of .cel-grass in such 
large numbers that they grow next to and over each other, and 
lose their natural hemispherical shapé, obscuring the normal 
color of the eel-grass, and giving a rough appearance to the blade. 
‘As the season advances, examination with a lens shows a 
greafer or smaller number of short, blunt protuberances issuing 
from the wartlike growths. Under the microscope they appear — 
to be composed of a number of cells placed end to end. Further 
observation demonstrates the fact that these cells, by division in 
two planes, give, rise to.a monostromatic frond. From this it. 
is but a step to establish a genetic connection between these hemi- 
SS structures and the fully grown fronds of P. naiadum. 
' The base itself is composed of a few layers of parenchymatous’ 
_ cells, the upper layer of which gives rise to the fronds, while the: 
ay 
