34 F. E. FKITSCH. 



no way attenuated ; the apical cell was more or less hemispherical, its outer membrane 

 being unthickened or barely thickened. The trichomes were frequently overgrown by 

 filaments of the subjacent Pltormitliuin, which were in part very closely applied to the 

 Oxcillntnria (fig. G4). Not uncommonly the apices of the trichomes bore a small 

 cluster of Bacteria (fig. G3). 



Apart from these typical specimens of the variety two peculiar forms were 

 noticed. In the one the apical cell of the trichome is produced into a point (f. 

 acum'mata, fig. G2), although such cases were very rare. The other form is 

 characterised by a tendency for the trichomes to coil up into a spiral or for 

 two parts of a trichome to become twisted spirally around one another, somewhat 

 as in Sj'iniUitd <litj>l<',r Wolle (f. sj>! rails, cf. fig. Gl). 



48. O.SCILLATORIA KOETTLITZI sp. U. 

 (PI. I., figs. 55-59.) 



Trichomatibus rectis vel modice nexuosis, sparsis in superficiem Phormidii repen- 

 tibus, obscure violaceis, hand vel vix inter cellulas constrictis, 7-9 p crassis ; cellulis 

 valde deplanatis, longitudine l^-2plo latioribus (long. cell. 3-4 '5 /A), contentu 

 cum paucis granulis, dissepimentis srepe indistinctis, granulis protoplasmaticis ssepe 

 magnis et fere confluentibus obductis ; apice recto, non attenuato, plerumque distincte 

 capitato ; cellula apical i saepe decolorata, sine granulis et plus minusve inflata, 

 membrana superne interdum modice incrassata. 



Hab. Gap pond, Winter Harbour; dry ponds, Winter Quarters, February, 

 1902. 



This species finds its place in Gomont's section Princijics and is perhaps most 

 nearly allied to 0. liinosa Ag., from which it differs in its smaller dimensions, in 

 the capitate habit and in the absence of attenuation. The terminal cell is certainly 

 a very characteristic feature ; in many of the trichomes it is prominently inflated 

 and quite devoid of contents, its membrane, however, being little if at all thickened 

 (figs. 55, 57, 58). The septa arc generally completely obscured by often coarse 

 protoplasmic granules, which mostly form a dense double row on either side of 

 the septum, although in some few cases there was but a single row of granules 

 (fig. 57). 



49. OSCILLATORIA TENUIS. 



Oscillatoria tennis Agardli, Alg. Decades, ii. (1813), p. 2.~> ; Gomont, torn, n/., pp. 220-221, PI. YIL, figs. 

 2 and 3. 



Diam. trich. = G-7 p.. 



Hab. Pond in eskcrs along shore of Western land, December 14th, 1902 ; 

 pond in eskers upon ice, half-way between Black and Brown Islands, January 3rd, 

 1903 ; pond in ice, off' Black Island, McMurdo Strait, December 31st, 1902. 



