425 
Recently, however, there have been published two monographs, 
the results of the patient working over of abundant materials by 
men of such experience and insight that the filamentous species of 
the Cyanophyceae are now arranged and defined in a most satisfac- 
tory fashion. 
The heterocysted forms, multiplying by means of hormogonia, 
are given in the “ Revision des Nostocacées Heterocystées” by 
Bornet and Flahault (Ann. Sci. Nat. (VII.)3: 323-381, 1886; 
4: 343-373, 1886; 5: 51-129, 1887; 7: 177-262, 1888), and the 
homocysted forms with the same kind of reproduction are given 
in the “ Monographie des Oscillariées” by Gomont (Ibid. VII. 
15: 263-368, p/. 6-74, 1892; 16: 91-264, pl. 1-8, 1892.) 
In both of these works a considerable number of species are 
credited to America, chiefly from specimens collected by Farlow, 
Collins, Holden, Wolle and the writer, but many more are to be 
expected and the writer hopes to be able to supply at some future 
time a full list of all found within our boundaries. 
The marine forms have been much more studied than those of 
the fresh waters, and have been mentioned in the papers of Far- 
low and Collins. The account of the species of the fresh waters 
found in Wolle (Fresh Water Algae of the United States, Bethle- 
ham, 1887) is, however, so confused and inexact as to allow no de- 
pendence to be placed upon it. Consequently we must, for the 
Present, accept as a summary of the knowledge of our species the 
information contained in the two monographs mentioned above 
and proceed to work out from them and with their aid. 
The following species, occurring for the most part in New 
England, seem to deserve mention. 
Calothrix Juliana (Menegh.) B. & F., known only in this coun- 
try from Mill Brook, Shelburne, N. H., where it was collected by 
Prof. W. G. Farlow, has occurred to the writer in Massopoag 
Brook, Sharon, Mass., and in Trading Cove Brook, Norwich, Conn. 
tt grew upon stones in small tufts consisting of a few erect paral- 
"lel filaments and could easily be distinguished by the touch, even 
©n stones thickly covered with diatoms and other forms. It is 
fasily distinguished from any other of our species by the absence 
of heterocysts. It grows upon wood as well as stones in the 
Quinebaug River, in Lisbon, Conn. 
