1903] Cushman, — New England Desmids, — II 253 
6. Cosmarium Becket Wille. Diam. 28 yp, length 31 p, isthmus 
9.5 a. The granules both in position and number are like the figure 
given by Wille. Frequent. Reported previously only from Orono, 
Maine. JVe to Massachusetts. (H.C. no. 379.) 
7. Cosmarium Botrytis Menegh. Diam. 60 y, length 71 y, isth. 
17 p. Very abundant and varies considerably. (H.C. no. 400.) 
Zygospores present — measuring with spines 80 p, without 62 u. (H. 
C. no. 382.) 
8. Cosmarium intermedium Delp. Diam. 40 p, length 56 y, isth. 
12.5 m. Occasional. Mew to New England. (H.C. no. 379.) 
9. Cosmarium laeve Rab., var. septentrionale Wille. Diam. 18 y, 
length 28 p, isth. 6 pw. Like Pl. xliii, f. 14, Wolle 1892. Slightly 
larger than the measurements given there. Common. (H. C. no. 
394-) 
10. Cosmarium protractum (Naeg.) Arch. Diam. 3o y, length 
34 p, sth. 9 u. This form corresponds to that of Pl. xx, f. 29, Wolle. 
1892, given as Cosmarium ornatum, var. minor. Reported previously 
from Orono, Maine. New to Massachusetts. Common. (H. C. no. 
394, 387, etc.) 
11. Cosmarium punctulatum Bréb. Diam. 28 p, length 31 y, isth. 
10 u. Very common. (H. C. no. 400.) | 
12. Cosmarium Quasillus Lund. Diam. 58 p, length 68 p, isth. 
14 4. Ends somewhat concave. Reported previously from Orono, 
Maine. New to Massachusetts. (H.C. no. 376.) 
13. Kuastrum verrucosum (Ehrb.) Ralfs. Diam. 68 u, length 8o 
p. isth. 16 w. The typical form. Occasional. (H. C. no. 382.) 
14. Mucrasterias Americana Ralfs. Diam. 100 m, length 125 p, 
isth. 28 p, diam. bas. pol. lobe 28 u. Like the figure of M. Americana 
Ralfs, forma genuina Ralfs given by Maskell except that the two spines 
on the polar lobes are sometimes lacking. Frequent. (H. C. no. 
346.) 
15. Micrasterias Americana Ralfs, var. This differs from any of 
the reported varieties and will be reported at a future time. (H. C. 
no. 343.) 
16. Staurastrum dejectum Bréb, var. mucronatum Ralfs. Diam. 
21 p, length 18,4, isth. 5 u. Smallform. Reported previously from 
Steep Brook, Massachusetts. Occasional. (H. C. no. 387.) 
17. Staurastrum echinatum Bréb. Diam. 40. m, length 42 y. 
More aculei than noted by Wolle, about one third larger, otherwise 
similar. Occasional. (H. C. no. 387.) 
