HoweE: PHYCOLOGICAL STUDIES 499 
genus, germinate precociously or while still attached to the thallus, 
so that the surface appears inconspicuously proliferous here and 
there. 
The only Dictyotas hitherto recognized from the Pacific coast 
of North America are, so far as we are aware, Dictyota crenulata 
J. Ag. from St. Augustin, Mexico, and D. Binghamiae of California. 
Of these, D. crenulata is characterized by strong marginal teeth, 
which are wholly lacking in D. Vivesii; by elongate or lingulate, 
broadly obtuse or subtruncate terminal segments, which are as 
broad as any part of the thallus; by a cortex that is for the most 
part conspicuously fenestrate in the Agardhian sense; by thicker- 
walled cells; and by a usually reticulate surface when dry. 
Dictyota Binghamiae is a coarser, thicker (275-500), more 
regularly dichotomous plant, with segments usually broader and 
their width better sustained towards the apices; its surface is 
beautifully reticulate when dry, and under the microscope the 
cortical cells, in most cases, show very clearly the differentiation 
in form and translucency that suggested the term ‘‘fenestrate”’ 
to J. Agardh. The cortex, too, of D. Binghamiae, towards the 
margins and in the older parts, often shows two or more layers 
of cells,—a character that is presumably responsible for its former 
identification with Glossophora Kunthii. The walls of the interior 
cells, that is, the walls that are perpendicular to the surface, are 
very firm and thick (5-30). . 
RHODOPHYCEAE 
PoRPHYRA LEUCOSTICTA Thuret in Le Jolis, Liste Alg.. Mar. 
Cherbourg 100. 1863 
San Felipe Bay, D. T. MacDougal, Feb. 1904. 
This species, so far as we are aware, has hitherto been attrib- 
uted, for the Pacific coast of America, only to Monterey Bay, 
California.* The Gulf of California specimens differ a little in 
color from most European and eastern American plants, tending 
rather more to brownish and blue-purple shades. 
The thallus is about 4op thick, surface jelly 8-114 thick; plants 
monoecious; antheridia in spots and streaks adjoining sporocarps; 
*Hus, H. T. A. Zoe 5: 63. 1900; Proc. California Acad. Sci. IIT. 2: 202. 
1902. 
