1901] Collins, — Notes on Algae 289 
NOTES ON ALGAE, —IV. 
FE. S. COLLINS. 
Spirulina Meneghiniana Zanardini, Atti R. I. Inst. Veneto, Vol. VI, 
p. 80, 1847. This species, hitherto found only as isolated filaments 
among other algae, was found July 27, 1901, on the Marblehead 
shore, Massachusetts, near Clifton station, in considerable quantity. 
It formed the principal constituent of a mixture in rock tide pools, 
above high water mark, but reached by spray in stormy weather. At 
the bottom of these pools was a light green impalpable sediment, like 
a chemical precipitate, the least motion of the water stirring it up so 
that great care had to be taken to secure it for specimens. The 
greater part of this sediment was S. Meneghiniana, characterized by 
the filaments, less than 2 » diam. coiled in a loose spiral, 3-5 u diam. ` 
S. subsalsa Oersted, the common species of this coast, has trichomes 
and spiral of about the same diameter as in S. Meneghiniana, but in 
the latter species the spiral is open, in the former the turns are nearly 
or quite in contact. See figures in Gomont, Monogr. des Oscill., p. 
ESO, AAA 
Cylindrospermum stagnale (Kuetz.) Born. and Flah., Revision des 
Nost. Het., part 4, p. 250, 1888. This plant formed a dense bluish- 
green or brownish scum on the surface of an artificial pond at the 
Pogy oil factory, Bristol, Maine, near Round Pond Village, July 16, 
1901. Its cylindrical spores distinguish it from all our other species 
except C. minutissimum Collins, while the smaller size of the latter, 
in all its parts, prevents any confusion of the two. Of the five 
established species of this genus recognized in Bornet and Flahault, 
Revision, in 1888, only two were credited to America; but now all 
five are known to occur in New England, as well as C. minutissimum, 
described in 1896. 
At Pemaquid Point, Maine, July 18, 19or, the writer found grow- 
ing on sloping rocks, exposed to the full force of the surf, which is 
very heavy here, what appeared to be a dense growth of Calothrix 
scopulorum (Web. and Mohr) Ag., common in such stations. On ex- 
amination by the microscope, however, the filaments were seen to have 
abundant pseudo-branches, showing it to be of the genus Dichothrix. 
Fresh water species of Dichothrix are not uncommon in New England, 
and in temperate countries generally, but there are only two marine 
