290 W. AND G. S. WEST 



52 Lyncjbya Kiitzingii Schmidle 



in Allg. hot. Zeitschr. 1896, iii, p. 58 ; Lemm. Alg. Brandenburg, 1907, p. 136. 

 Leibleinia martensiana Kiitz. 



Crass, fil. 2-3 M. 



Hob. In ponds on Mt. Erebus. Coast Lake. Blue Lake. 



Var. distincta (Nordst.) Lemm. in Engler's Botan. Jahrbuch. xxxv, 1905, p. 620. 

 L. martensiana var. distincta Nordst. Alg. aq. dulc. et Char. Sandvic. 1878, p. 4. 

 L. distincta (Nordst.) Schmidle, 1896. L. subtilis West in Journ. Roy. Micr. Soc. 

 1892, p. 29, t. 10, f. 58. 



Crass, fil. 1.5 n. 



Hob. In pond, Cape Royds. 



In his " Sylloge Myxophycearum " Dr. Achille Forti places L. subtilis as a distinct 

 species, owing perhaps to an error in his description. His " articulis diam. ad 2-plo 

 longioribus" should be " articulis diam. ad 2-plo brevioribus" 



53 Lyngbya limnetica Lemm. 



in Botan. Centralbl. Bd. 76, 1898, p. 154; Alg. Brandenburg, 1907, p. 135 et 

 p. 102, f. 8. 



Crass, fil. IM; long. cell. 1-1.4 /. 



Hob. In pond, Cape Royds. Green Lake. 



54 Lyngbya erebi sp. n. (PI. XXV, Figs. 72a-72!) 



L. strato valde expanse, cartilagineo, 3-5 mm. crasso, obscure serugineo vel vix 

 colorato ; filis flexuosis, densissime tortuoso-intricatis ; vaginis tenuibus arctis, validis 

 et achrois, crebro vacuis; trichomatibus angustissimis pallide serugineis, inter 

 cellulas non constrictis, apicibus rectis, obtusis et non attenuatis ; cellulis diametro 

 trichomatis paullo brevioribus, contentu homogeneo. 



Crass, fil. et trich 0.9 M ; long. cell. 0.6-0.8 n. 



Hab. In pond on Mt. Erebus. 



This narrow Lyngbya formed a thick and very tough cartilaginous stratum, 

 almost destitute of colour, owing to a great extent to the enormous number of 

 empty sheaths of which it was composed. The sheaths themselves, although 

 so thin, are both strong and persistent, and form a densely contorted mass 

 difficult to tease out. The trichomes are very pale aBi-ugiiious green, and show no 

 signs of granulation. 



In size L. erebi compares with the smallest of the plankton- Lyngbyas, but is 

 entirely different from them in habit. 



It should be compared with Phormidium glaciale, from which it is distinguished by 

 the nature of its stratum and its strong persistent sheaths, both of which characters 

 give an entirely different aspect to the plant. 



