FRESHWATER ALGJS 295 



of the same thickness as the marine 0. subuliformis, and the gradual attenuation 

 towards the apex is a very similar character. 



69 Oscillatoria formosa Bory 



1827 ; Kutz. Tab. Phycol I, t. 41, f. 8 ; Gomont, I.e. p. 250, t. 7, f. 16. 



Crass, trich. 4.8 p. 



Hob. Coast Lake, scarce among 0. tennis, 0. subproboscidea, and 0. limosa. 



70 Oscillatoria chlorina Kutz. 



Phyc. gener. 1853, p. 185 ; Spec. Alg. 1849, p. 239 ; Tab. Phycol. I, p. 28, t. 39, 

 f. iii; Gomont, l.c. p. 243. 



Crass, trich. 3.5-4 M; long. cell. 3.8-5.5 M. 

 Hob. Green Lake. In pond, Cape Koyds. 



71 Oscillatoria terebriformis Ag. 



1827 ; Gomont, l.c. p. 254, t. 7. f. 24. 

 Forma tennis. (PI. XXVI, Fig. 98) 



Forma trichomatibus 3 M crassis, cellulis subquadratis ; dissepimenta granulata; 

 cellula apicali subtruncata. 



Hob. In pond, Cape Royds. 



72 Oscillatoria amphibia Ag. 



1827 ; Gomont, l.c. p. 241, t. 7, f. 4, 5. 

 Crass, trich. 2-2.1 n. 



Hab. Coast Lake, infrequent among various Myxophyceae. 

 Var. robusta var. n. (PI. XXVI, Fig. 102) 



Var. trichomatibus crassioribus ; dissepimenta granules plures pulcherrime 

 coaruleas utrobique prsebens. 

 Crass, trich. 3.5 M. 

 Hob. In pond, Cape Royds. 



73 Oscillatoria deflexa sp. n. (PL XXV, Figs. 95-97) 



0. trichomatibus sparsis et nonnunquam in csespitibus parvis subspiraliter contortis 

 inter alias Myxophycearum natantibus, rectis, serugineis, apices versus gradatim 

 attenuatis et juxta apicem subiter deflexis; inter cellulas non constriotis, dissepi- 

 menta non granulata ; cellulis diametro trichomatis 2-2^-plo longioribus, cytioplasmate 

 homogeneo ; cellula apicali attenuata obtusa, calyptra nulla. 



Crass, trich. 0.9-1 n ; long. cell. 2.4-2.9 M ; long. part, deflex. apic. 4.2-4.8 /u. 



Hab. Green Lake. Coast Lake. 



This species should be compared with 0. subtilissima Kiitz., 0. Kutzingiana Nag., 

 and 0. angustissima W. & G. S. West, from all of which it differs in the apex of the 

 trichomes and other points. 0. minuta Hansg. may also be an allied species. 



BRIT. ANTARCT. EXPED. 1907-9. VOL. I. N 



