32 F. E. FRITSCH. 
(Menegh.) Gom., but apart from other differences, the trichomes are more moniliform 
than they are in that species. The longer cells, granulated dissepiments and more 
markedly moniliform character distinguish P. frigidum from P. glaciale W. and 
G. 8. West (op. cit., p. 291, 292). 
42, PHORMIDIUM ANGUSTISSIMUM. 
Phormidium angustissimum W. and G. 8S. West, “ Welwitsch’s African Freshwater Algae,” Journ. Bot., 
1897, pp. 298-299. 
Hab.—F reshwater pond in eskers upon ice, half way between Black and Brown 
Islands, January 38rd, 1903; freshwater pond in ice off Black Island, McMurdo 
Strait, December 31st, 1902. 
In the material from the first habitat the septa were very indistinct and 
constriction was scarcely obvious. In this latter respect the specimens were more like 
P. treleasi Gom., which G. 8. West (Algze from hot springs, Journ. Bot., 1902, p. 245) 
has suggested may be identical with 27. angustissimum. In some cases the trichomes 
tapered a little at the apex. The material from the second habitat was quite typical. 
43. PHORMIDIUM ANTARCTICUM. 
(Plo ties: 41=73;) 
Phormidium antarcticum W. and G. 8. West, Rep. Brit. Antarct. Exped., vol. i. (1911), p. 292, Pl. XXY., 
figs. 754-754. 
Forma trichomatibus modo laxissime spiraliter contortis vel non spiraliter. 
/lab.—Pond some distance behind hut, Cape Adare, January 9th, 1902. 
The material of this species occurred intermingled with Chlamydomonas 
subcaudata, C. intermedia, ete., i.e. the consorts were in part the same, as in the 
material examined by Messrs. West. The filaments agreed in all respects with those 
deseribed and figured by the latter authorities, except that they did not show the 
marked spiral character evident in Messrs. West’s figures. They were sometimes 
formed into a very lax and irregular spiral, but more commonly a spiral character 
was not obvious at all, the filaments being almost straight or curved or looped in 
various ways. 
The diffluent sheaths of the filaments were rarely visible, but were often indirectly 
rendered obvious by the marked adhesion of foreign matter (in the shape of minute 
particles) to the surface of the filaments. The transverse walls were very indistinct in 
unstained material, but after staining with methylene blue they appeared as rather 
thick transverse bars. 
The advisability of referring this form to the genus Phormidium may be 
questioned. Except for the diffluent character of the sheaths, it is a Lyngbya, and it 
might prove better to confine the limits of the former genus to such forms as consist 
of sheets of agglutinated filaments. 
