BY G. I. PLAYFAIR. 137 



Var. SUBTRUNCATA, n.vai'. (PI. viii., f.17-19). 



Celluke oblongae interdum pjene cylindraceaj, lateribus minus 

 arcuatis, apicibus subtruncato-rotundatis. 



Cell, matric. elliptic. 80 x 40; cell. veg. vel autosp. 50 x 20, 

 50 X 26, 54 X 24, 60 x 32, 61 x 32, 62 x 26, 62 x 32, 70 x 32/x. 



Rookwood (107); Lismore ( 240). 



Cylindrocystis oralis Turn., I.e., T. i., f.5 (fig. dextr.). Turner 

 gives two different forms for his Ci/l. ovalis, the right-hand one 

 one of which can hardly be described as oval. I have sepaiated 

 this form, therefore, as var. snbtruncafa. It is more common 

 than the type, and is distinctly oblong, verging sometimes on 

 subcylindrical, with subtruncately rounded ends. In specimens 

 found with the type in sample No. 107, the chloi'oplasts were 

 digitate, but I have noted others at Lismore with chloroplasts of 

 the usual discoid character. 

 Forma. 



Apicibus late-rotundatis nee subtruncatis. 



Cell. veg. 70 x 32/x. 



Auburn (140). 



Var. CYLiNDRACEA, n.vax\ (PI. viii., f. 20-22). 



Cellulae plus minusve distincte cylindracese; lateribus levissime 

 arcuatis subparallelis; apicibus late-rotundatis vel subtruncatis. 



Cell veg. vel autosp. 52 x 28, 66 x 28, 67 x 40, 86 x 32//. 



Rookwood (107). 



In this foi'm, the sides are nearly parallel, and only slightly 

 arched. Slender specimens are quite cylindrical, the broader 

 more oblong. I have noted that, in this variation, it may, per- 

 haps, occur also in the other forms, the cell is provided with 

 what appear to be two, large, pale reddish-brown pyrenoids, one 

 in either half of the cell. In this condition, the cell simulates a 

 CyHndrocystis very closely indeed. The same occurs in 0. 

 lacustris var. 2^'^^^densis mihi, in which form this presumed 

 pyrenoid is sometimes pale brown and sometimes pale green. I 

 am inclined to believe, however, that these bodies are not pyre- 

 noids, but nuclei with a layer of chlorophyll or oil-drops surround- 

 ing them. Pyrenoids, when they occur, are found, one in each 



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