FRESHWATER ALG.E 289 



Plectonema notatum than with any of the other small species of the genus. The 

 false branches were rare and solitary, and the cells were sometimes twice as long as 

 broad. 



Genus LYNGBYA C. Ag. 



48 Lyngbya shacUetoni sp. n. (PL XXV, Figs. 68, 69) 



L. filis sparsis inter stratum algarum Myxophycearum, subrectis ; vaginis firmis 

 achrois distincte lamellosis; trichomatibus Isete aerugineo-coeruleis, inter cellulas non 

 constrictis, massa intercellular! inflate- torulosa et refringenti crebro interruptis, 

 apicibus rectis ; cellulis diametro trichomatis quadruple brevioribus, cytioplasmate 

 minute granulate; cellula apicali elongato-conica et pallidissime seruginea. 



Crass, fil. 12-12.5 /*, trich. 8.5-9.5 M ; long. cell. 2-2.4 M. 



Hob. Lake at Hut Point. 



This species should be carefully compared with L. nigra Ag., which is the only 

 species with which it might be confused. The sheaths of L. shackletoni are much 

 thicker than those of L. nigra and are evidently lamellose ; the trichomes are 

 also frequently interrupted by lens- shaped masses of brightly coloured, highly 

 refractive material, and the apical cell, although markedly conical, has no calyptra. 

 Moreover, the end of the trichome is never capitate. 



49 Lyngbya martensiana Menegh. 



1837 ; Gomont " Monogr. des Oscillar.," Ann. Sci. Nat. 7 C serie, Bot. xvi., 

 1892, p. 165, t. 3, f. 17. 



Crass, fil. 8-9 M, trich. 6-7 M. 

 Hob. Blue Lake. 



50 Lyngbya cerugineo-coerulea (Kiitz.) Gomont, 



l.c. p. 166, t. 4, f. 1-3. 



Crass, fil. 7 M, trich. 5.7. 

 Hob. Ponds on Mt. Erebus. 



51 Lyngbya murmyi sp. n. (PI. XXV, Figs. 70, 71) 



L. filis inter algas varias Myxophycearum libere natantibus, stratum non formatis, 

 flexuosis ; vaginis tenuibus arctissimis et achrois ; trichomatibus laete serugineo- 

 coeruleis, inter cellulas non constrictis, apicibus rectis, non attenuatis, obtusis vel 

 rotundato-truncatis; cellulis diametro trichomatis Ij-lf-plo longioribus, cytio- 

 plasmate homogeneo cum granulis magnis 1 vel 2 prope dissepimenta utrobique 

 aggregatis. 



Crass, fil. 3.1-3.3 /*; long. cell. 5-6 /*. 



Hal). Green Lake. 



This species probably stands nearest to L. versicolor (Wartm.) Gomont, but is 

 distinguished by its free-floating habit, its much thinner sheaths, which are not 

 agglutinated, and by the coarsely granulate dissepiments. 



