298 W. AND G. S. WEST 



Colonies small and compact, consisting of eight or sixteen regularly arranged 

 cells. Cell- contents of a brilliant blue- green colour and granulose. 



Genus MICROCYSTIS Kiitz. 



82 Microcystis stagnates Lemm. 



in Forschungsber Biol. Stat. PI on. X., p. 150. Polycystis pallida Lemm. P. elongata 

 W. & G. S. West. 



Diam. cell. 1.7-1.8 n. 



Hob. Coast Lake. 



RIVULARIACEJ; 



Genus CALOTHRIX Ag. 



83 Calothrix epiphytioa W. & G. S. West 



" Welw. Afric. Freshw. Alg.," Journ. Bot. 1897, p. 240. 

 Crass, fil. ad bas. 7.5-8 M ; crass, trich. ad bas. 5.4-5.8 M. 

 Hob. Lake at Hut Point. 



84 Calothrix sp. (PI. XXV, Figs. 55-57) 



C. strato tenui submembranaceo serugineo-coaruleo ; filis subbrevibus dense 

 intricatis et contortis, paullo attenuatis sed non in pilum productis; trich omatibus 

 cceruleis, gradatim attenuatis, cellula terminali obtusa ; cellulis subtorulosis, rotundato- 

 rectangularibus, diametro trichomatis paullo brevioribus vel nonnunquam duplo 

 brevioribus; heterocystis basilaribus singulis et inflate- hemisphsericis. 



Crass, fil. ad. bas. 10-12 M; crass, trich. ad bas. 8-9.6 M. 



Hob. Blue Lake. 



It is highly probable that this is as yet an unnamed species of Calothrix, but we do 

 not feel justified in expressing a definite opinion until more material has been examined. 

 It occurred in very small thin patches, of a most intense blue- green colour, among 

 the tough sheets of Phormidium glaciale. The filaments were much contorted, densely 

 intricate, and quite without any definite arrangement in the stratum. The attenuation 

 was slight, and none of the plants showed any signs of hair- like apices. Thesubtorulose 

 cells are also a feature of the trichomes. 



