126 Rhodora [JuLy 
culata Say. lt is often mixed with Microchaete grisea Thuret, Calo- 
thrix species, and other small algae. 
P. rimosa Kiitzing, Phye. Gen., p. 273, 1843; Collins, RHopora, 
Vol. V. р. 207, 1903; Collins, Holden & Setchell, P. B.— A., No. 971, 
1902. ‘There is nothing to add to what was given in the writer's note 
on the first occurrence in America; no other locality has been re- 
ported. 
P. Morsei n. sp. Filamentis basilaribus irregulariter contortis, plus 
minusve concretis, cellulis rotundatis, 8-15 # diam., saepe longitudi- 
naliter divisis, membranam subparenchymaticam bi-polystromaticam 
formantibus; filamentis erectis ad 2 mm. altis, 7-11 # diam.; cellulis 
1-2 diam. longis, cylindricis vel leviter moniliformibus; sporangiis 
ovoideis vel pyriformibus, stratum basale insidentibus, sessilibus vel 
ad pedicellum paucicellulare. 
Basal filaments irregularly contorted, more or less united; cells 
rounded, 8-15 # diam., often divided longitudinally and forming a 
subparenchymatous membrane of two or more layers; erect filaments 
up to 2 mm. high, 7-11 » diam., cells 1-2 diam. long, cylindrical or 
slightly moniform; sporangia ovoid or pyriform, on the basal layer, 
sessile or on a few-celled pedicel. On woodwork, Atlantic City, New 
Jersey, Prof. S. R. Morse. 
In this species there seems to be a differentiation between the fer- 
Ше and the assimilative growths from the basal layer; the former 
are short, in many cases nothing but the sporangium itself; the lat- 
ter are longer than in any other species of the genus. After а sporan- 
gium is emptied another may be produced by the same filament, but 
while in P. Heinschii the sporangia are at considerable intervals on 
a long filament, in P. Morsei they are "nested," usually only a single 
cell being produced to support the new sporangium. The cells of 
the basal filaments divide longitudinally, by a plane approximately 
parallel to the substratum. The color is yellowish. The writer 
takes pleasure in giving to this species the name of Prof. Silas Rutil- 
lus Morse of the New Jersey State Museum, who first called his 
attention to it, and to whom we are indebted for much of our knowl- 
edge of the algae of the New Jersey coast. 
P. MARITIMA (Kjellm.) Rosenvinge, Gronlands Havalger, p. 933, 
fig. 43, 1893; Chaetophora maritima Kjellman, Spetsbergens Alger 
р. 51, РІ. IV, figs. 15-16, 1877. Frond subspherical, 1-3 mm. diam., 
with basal layer not strongly developed; erect filaments 6-10 y diam., 
