1908] Cushman,— New England Species of Micrasterias. 103 
8. MicRASTERIAS CONFERTA Lund., var. HAMATA Wolle, Bull. 
Torrey Club, 1883, p. 19, pl. 27, fig. 1; Desm. U. S., 1884, p. 114, 
pl. 38, figs. 3, 4; W. & G. S. West, Some N. A. Desm., 1896, p. 241, 
pl. 14, figs. 8, 9; Brit. Desm., 1905, p. 90, pl. 43, figs. 10, 11. Cells 
of medium size, deeply constricted, with a linear sinus, semicells five 
lobed, interlobular sinuses narrow except those between the lateral and 
polar lobes, these being widely gaping, polar lobe cuneate, the distal 
end broadly extended laterally and the angles uncinate with tooth-like 
projections and with two pairs of small teeth at either side of the apical 
notch, lateral lobes twice divided dichotomously by shallow sinuses, cell 
wall coarsely punctate. Length 106; breadth 100 y, polar lobe, 43.4 
4, isthmus 12.4 и. Me.: Spencer Pond, East Middlesex (Н. C. no. 
604)! Mass.: Mt. Everett, Mount Washington (Wolle): Lake Quin- 
sigamond, Worcester (Stone). 
9. MICRASTERIAS APICULATA (Ehrenb.) Menegh., Synops. Desm., 
1840, p. 216; W. & G. S. West, Brit. Desm., 1905, p. 97, pl. 47, figs. 
1,2. M. fimbriata, forma apiculata Wolle, Desm. U. S., 1884, p. 110, 
pl. 36, fig. 2. M. furcata Wood, Fr. Alg., 1873, p. 144, pl. 13, fig. 5. 
Euastrum apiculatum Ehrenb., Organ. kl. Raum, 1834, p. 245; Infus., 
1838, p. 161, pl. 12, fig. II. Cells large, slightly longer than broad, 
sinus deep, narrowly linear, opening outward; semicells five lobed, 
polar lobe exserted, sides nearly parallel, except at the distal end which 
is expanded, angles with a pair of stout diverging spines, on the inner 
side a stout incurved spine at each side and a smaller spine on either 
side of the median notch; lateral lobes nearly equal, each dichoto- 
mously twice divided, the resulting divisions each with a pair of curved 
spines, all sinuses narrow except those between the lateral and polar 
lobes, these opening much more widely; surface of the cell with many 
minute spines, with four larger ones just above the isthmus in each 
semicell and arranged in a quadrate manner. Length 240—254 y, 
breadth 200-217 u, polar lobe 42-46 y, isthmus 31 и. N. H.: Hill's 
Pond, Alton (H. C. по. 666)! Mass.: Medford! There is considerable 
variation in the spines of the polar lobe. In some cases they are very 
large and strongly curved. 
9a. MICRASTERIAS APICULATA, subsp. FIMBRIATA (Ralfs) Nordst., 
Bornh. Desm., 1888, p. 190; W. & G. S. West, Brit. Desm., 1905, 
р. 99, pl. 46, fig. 6, pl. 47, figs. 2, 3. M. fimbriata Ralfs, Brit. Desm., 
1848, p. 71, pl. 8, fig. 2; Wolle Desm. U. S., 1884, p. 109, pl. 36, fig. 1. 
M. fimbriata var. nuda Wolle, Bull. Torrey Club, 1880, p. 45; Desm. 
