108 Rhodora [JUNE 
Pond, North Conway! Mass.: Lake Quinsigamond, Worcester 
(Stone); Tewksbury! Medford (H. C. no. 712)! Wellesley! Car- 
vers Pond, Bridgewater! Lake Watuppa, Fall River! Nokechoke 
Lake, Westport! Milford Pond, Swansea (Н. C. no. 669)! В. I.: 
Worden's Pond, near Providence (Bailey); Nyatt (Н. C. no. 636)! 
As shown by Johnson this species is very variable, all gradations 
existing between var. simplex Wolle and the typical form, and the two 
semicells of a single specimen often being considerably different. The 
angle at which the lateral lobes diverge is also very variable. 
15a. MICRASTERIAS RADIATA, var. dichotoma (Wolle) n. comb.; 
M. dichotoma Wolle, Bull. Torrey Club, 1884, p. 14; Desm. U. S., 
1884, p. 111, pl. 52, fig. 2. Similar to the type but with the lobes 
much more spreading and drawn out laterally. Length 190-250 p, 
breadth 155-200 y, polar lobe 93-111 y, isthmus 13-18 и. Mass.: 
Lake Quinsigamond, Worcester (Stone); Tewksbury (Lagerheim); 
Nokechoke Lake, Westport (H. C. no. 645)! This seems best con- 
sidered a variety of M. radiata as it differs in but minor characters, 
the drawn out condition of the lobes being the main thing that dis- 
tinguishes it. 
16. MicRASTERIAS CRUX-MELITENSIS (Ehrenb.) Hass., Br. Alg., 
1845, p. 386, pl. 90, fig. 7; Ralfs, Brit. Desm., 1848, p. 73, pl. 9, 
fig. 3; Wolle, Desm. U. S., 1884, p. 111, pl. 35, fig. 3; W. & С. 5. 
West, Brit. Desm., 1905, p. 116, pl. 53, figs. 1-3.  Euastrum crux- 
melitensis Ehrenb., Entw. d. Inf., 1832, p. 82. Mass.: Lake Quinsig- 
amond, Worcester (Stone). This is the only New England record 
for this species. I have never seen specimens which I could refer to 
this species. 
17. MICRASTERIAS AMERICANA (Ehrenb.) Ralfs, Brit. Desm., 
1848, p. xix; Wood, Fr. Alg., 1873, p. 143, pl. 12, fig. 17; Wolle, 
Desmi. U. S., 1884, p. 112, pl. 32, fig. 2; W. & G. S. West, Brit. Desm. 
1905, p. 117, pl. 53, figs. 4, 5, pl. 54, figs. 1-3. M. morsa Ralfs, Brit. 
Desm., 1848, p. 74, pl. 10, fig. 1. Еназітит americanum Ehrenb. 
Mikr. Leb. Sud. u. N. Amer., 1843, p. 413, pl. 4, fig. I. 15. Euas- 
trum No. 4 Bailey, Amer. Bacill., 1841, p. 295, pl. 3, fig. 25. Cells 
of medium size, slightly longer than broad, deeply constricted, sinus 
opening outward, semicells five lobed, polar lobe large and broadening 
distally, apex widely retuse, each angle extended into a broad process, 
denticulate at the end, from near the base of each of these processes is 
a shorter similar process, each on the opposite side of the polar lobe; 
