302 MESSRS. W. WEST AND G. 8. WEST ON 
proportionately longer cells, its somewhat retuse lateral margins, 
and in the more emarginate thickening in the centre of the semi- 
cells, which is also devoid of scrobiculation. 
82. CosMARIUM ANGULARE, Johnson, in Bull. Torr. Bot. 
Club, xxi. (1894), no. 7, p. 290, pl. 211. f. 14. 
Long. 30 p; lat. 25 p. 
Hab. Baton Rouge, La., scarce. 
83. C. RECTANGULARE, Gun. in Rabenh. Flor. Europ. Alg. iii 
p. 166 (1868).—C. gotlandieum, Wittr. (1872). 
Long. 38 u; lat. 30 p; lat. isthm. 10 u; crass. 18 p. 
Hab. Laconia, N.H., occasional. 
84. C. nova TUM, Wolle, Desm. U. S. p. 65, pl. 16. f. 16. 
Var. DEPRESSUM, n. var. (Pl. 18. figs. 2, 3.) 
Var. cellulis circiter 14-plo latioribus quam longis, apicibus 
depressis, sinu angustiori et apice acuto; pyrenoidibus singulis. 
Long. 20-22 p; lat. 30-31 p ; lat. isthm. 6-7 p. 
Hab. Tallahassee, Florida (H. J. no. 551). 
85. C. SrwosrEGos, Schaarschm. in Magyar. Tudom. Akad. 
Math. s. Termész. Kézlem. xviii. p. 266, t. 1. f. 12. 
Long. 10; lat. 10 p; crass. 5 p. 
Hab. Seattle, Wash., frequent. 
Var. optusius, Gutw. in Nuov. Notarisia, iii. p. 21. 
Long. 10; lat. 8 u; lat. isthm. 8 p; crass. 4p. 
-Hab. Laconia, N.H., occasional. 
86. C. Pyaw EUM, Arch. in Quart. Journ. Mier. Sci. 1864, 
p- 174, pl. 6. ff. 45-49 ; West in Journ. Linn. Soc. (Bot.), X3 
p. 146, pl. 20. f. 24. 
Var. ScHITEPHACKIANUM, nod.—C. Schliephackianum, Gru". 
in Rabenh. Flor. Europ. Alg. iii. p. 167 (1868). . 
Var. semicellulis a vertice visis tumore prominentiori utrobique 
instructis. 
Long. 12 p; lat. 10-12 p; lat. isthm. 35-5 p. 
Hab. Bridgeport, Conn., and New Baltimore, Mich., commo? : 
Laconia, N.H., occasional. 
Grunow's species appears to us to differ from C. pygmems 
Arch., only in the more prominent central protuberance, an 
cannot therefore stand as a distinct species. In vertical vie" 
C. pygmæum is subrhomboidal, with a faint indication of a cen 
