1908] Cushman,— New England Species of Micrasterias. 101 
fida may be seen to be variable in the same lot of material within 
certain limits. 
4. MicnasrERIAS ARCUATA Bailey, Micr. obs., 1851, p. 37, PLIL 
fig. 6; Wolle, Desm. U. S., 1884, p. 117, pl. 38, fig. 5. Mass.: Lake 
Quinsigamond (Stone). 
4a. MICRASTERIAS ARCUATA, var. EXPANSA (Bailey) Nordst., 
Alg. Brasil, 1877, p. 23, fig. II, 5, 6, and b in text. M. expansa 
Bailey, Micr. obs., 1851, р. 37, pl. 1, fig. 7; Wolle, Desm. U. S., 1884, 
p. 117, pl. 37, fig. 12. Mass.: Lake Quinsigamond, Worcester 
(Stone). These records are all there are for New England. 
5. MIcRASTERIAS DEPAUPERATA Nordst., var. Кітснкілі (Wolle) 
W. & G. S. West, Some N. Amer. Desm., 1896, p. 239; Cushman, 
Notes on Micrasterias, 1904, p. 396, fig. 2 in text. Micrasterias 
Kitehelii Wolle, Bull. Torrey Club, 1880, p. 45, pl. 5, fig. M; Desm. 
U. S., 1884, p. 116, pl. 37, figs. 1-3. Cells of medium size, about as 
long as broad, deeply constricted, sinus open: semicells barely five 
lobed, the lateral lobes being divided by a rounded incision of slight 
depth, polar lobe widely spreading, separated from the lateral lobes 
by a fairly deep, broadly rounded incision, the width across the distal 
part of the lateral lobes, slightly less than the entire width of the cell. 
Extremities of all the lobes bifid. Length 125 м, breadth 125 н, polar 
lobe 75-100 м. Mass.: Gilder Pond, Mt. Everett, Mount Washington 
(Wolle). Although I collected in Gilder Pond in May 1907 I failed to 
find this or any other form of M. depauperata. Due to the late spring 
few desmids were present. Wolle’s material was collected in August. 
ба. MICRASTERIAS DEPAUPERATA Nordst., var. WoLLEI Cushman, 
Notes on Micrasterias, 1904, p. 396, fig. 3 in text. M. Kitehelii Wolle, 
var., Desm. U. S., 1892, p. 129, pl. 42, fig. 2. M. depauperata W. & 
G. S. West, Some N. A. Desm., 1896, p. 238, pl. 14, fig. 1. Cells larger 
than in the preceding, somewhat longer than broad, the lateral lobes 
even less divided by a very shallow sinus, apical lobe narrower, width 
across the distal portion of the lateral lobes only about three fourths of 
the whole width of the cell; cell wall punctate. Length 140—155 y, 
breadth 130-145 м, polar lobe 90-100 y, isthmus 21-27 и. N. H.: 
Pudding Pond, North Conway, rare! Mass.: Tewksbury (Lager- 
heim); Lake Watuppa, Fall River, common (И. C. no. 32)! "This 
is the only form of M. depauperata that I have seen from New 
England. It seems to be a rare species and in but one of the localities 
was it at all common. 
