272 W. AND G. S. WEST 



This is normally a submarine species, and although in its present habitat there 

 would doubtless be a substratum containing a considerable percentage of saline 

 constituents, yet this locality was the least saline of any from which species of 

 Ulothrix were obtained. Some of the diatoms amongst the mass of Ulothrix were 

 typically submarine. 



4 Ulothrix cequalis Kiitz. 



Phyc. Germ. 1845, p. 197 ; Spec. Alg. 1849, p. 347 ; Tab. PJiycoL II, 1852, t. 89, f. 1. 

 Hormiscia cequalis Rabenh. Flor. Europ. Alg. Ill, 1868, p. 363. 



U. filis exacte cylindricis, subrectis vel leviter flexuosis, cellulis diametro 0.7-1 .3-plo 

 longioribus; chromatophora parietali subparva, sublobata, plerumque unilateral! ter 

 disposita, pyrenoidibus nullis. 



Diam. cell. 14-20 M; long. cell. 10-25 M- (PL XXIV, Figs. 1, 2) 



Hob. Dried-up Lake, Cape Royds. 



As the characters of Ulothrix cequalis are still somewhat obscure, we have given 

 a concise description and figures of the Antarctic specimens. We attach no importance 

 to the absence of pyrenoids from the chloroplasts, as this condition is frequent 

 throughout the genus when the chloroplasts are small and only occupy about half 

 the cell. 



Both Ulothrix cequalis and U. tenerrima have been found in the snow- flora of 

 Spitzbergen. Cf. Lagerheim \nNuova Notarisia, ser. vi, 1895, p. 6 (sep.). 



Forma filis paullo tenuioribus, chromatophora majori cum pyrenoide singulo vel 

 rare pyrenoidibus birds. 



Diam. cell. 13-16 M; long. cell. 11.5-18 M - (PL XXIV, Figs. 3, 4) 



Hob. Green Lake. 



This form was not uncommon among various Myxophyceae. 



PRASIOLACE./E 



Genus PBASIOLA Ag. 



5 Prasiola crispa (Lightf.) Menegh. 



Kiitz. Phyc. gener. 1843, p. 295 ; Gay, Recherches sur la developpement et la 

 classif. Alg. Vertes, Paris, 1891, p. 86. 



Hob. On the ground and in a small pond, Cape Royds ; also covering a consider- 

 able area of the ground below the Penguin Rookery. Near Blue Lake, on the ground. 

 Also on the ground 5j miles south of Cape Irizar. 



Nearly all the specimens of the genus Prasiola examined from the Antarctic region 

 were without doubt forms of P. crispa. 



In the vicinity of Cape Royds the Hormidium- and Schizogonium- stages were 



iquent. The cells measured 9-12 /u. in diameter, and the filaments were mostly 



rather short. In the Penguin Rookery, where the necessary conditions for the growth 



of this Alga were fully realised, it occurred in great abundance. The filaments showed 



