1903] Cushman, — Desmids of Bridgewater, Massachusetts 81 
C. suborbi.ulare Wood. Frequent. 
C. amoenum var. tumidum Wolle. Frequent. 
C. Schliephackeanum Grun. Rare. 
C. ornatum Ralfs. Common, 
Zetmemorus Brebissonii (Menegh.) Ralfs. Fairly frequent. 
Arthrodesmus octocornis Ehrb. Frequent. 
Euastrum magnificum Wolle. Rare. 
. ansatum Ralfs. Common. 
. affine Ralfs. Common. 
. verrucosum (Ehrb.) Ralfs. Fairly common. 
.gemmatum Breb. Not common. 
. elegans Kg. Fairly common. 
. integrum Wolle. Frequent. 
Xanthidium antilopaeum (Breb.) Kg. var. PoZymazum Nord. Few 
specimens found. 
Micrasterias radiosa ( Ag.) Ralfs. Common. 
M. furcata (Ag.) Ralfs. Not common but have found frequent 
specimens, some deformed ones with the second pair of basal arms 
wanting. 
M. Americana (Ehrb.) Kg. Not rare, but not occurring as fre- 
quently as other forms. 
M. Americana var. recta Wolle. Rare; seen only a few times. 
M. Mahabuleshwarensis Hobson. Fairly frequent. 
M. laticeps Nord. Fairly frequent. 
M. muricata Bailey. Frequent. 
Staurastrum polymorphum Breb. Common, in various forms, vary- 
ing in semi-cells of the same individual. 
S. macrocerum Wolle. Rare. 
S. leptocladum Nord. Not common. 
S. anatinum Cooke & Wills. Fairly frequent. 
S. muticum Breb. Common. 
S. orbiculare (Ehrb.) Ralfs. Common. 
S. crenulatum Naeg. Fairly common. 
S. punctulatum Breb. Fairly common. 
Also the following species of Pediastrum may be mentioned here . 
as common occurring with the Desmids. 
Pediastrum Boryanum (Turpin) Menegh. 
P. pertusum Kg. 
P. Ehrenbergii (Corda) A. Br. 
BRIDGEWATER, MASSACHUSETTS. 
by fy m i by by 
