BY G. I. PLAYFAIR. 109 



Var. MINIMUM, n.var. (PL iii., f.23). 



Cellulse minimae cylindracse, eiidochroma in lamina tenui parie- 

 tali disposita, pyrenoidibus singulis minutis. 



Cell. long. 22, lat. 7 /x. 



Casino (14). 



The cliloroplast, when in good condition, extends the whole 

 length of the cell, but very often is reduced to a band in the centre, 

 as in Myxonema. Eichler, Okolic Miedzyrzeca, 1892, T.ix, f. 6, 

 records a size larger than this (cells 46 x 12), but with the reticu- 

 late chloroplasts of the type. 



Var. NODOSUM, n.var. (PI. iii., f.24). 

 Forma in extremis cellulis leviter inflata, endoclu-oma reticulata. 

 Cell. long. 100-300, lat. 20-54 /x. 

 Casino (14). 



In many instances, I noted a tendency for the pyrenoids to run 

 in long spirals across the cells. 



Var. Bernardii, n.var. (PI. iii., f.25). 



Forma cellulis maximis, in extremis inflatis, membrana crassa, 

 endochroma dilute luteolo-viridi in granulis minutis diffusa, pyre- 

 noidibus majoribus granulalis. 



Cell. long. 1020; lat. centr. 103, extr. 140, membr. ad 10//. 



Casino (14). 



Cf. Bernard, Desm. et Protoeocc, PL xv., f. 536, 537. All the 

 above forms were found together in the same gathering. Bernard, 

 I.e., records them also from Java. They are, of course, all stages 

 of growth, but are quite distinct enough to be worth naming. It 

 seems to me also that this plant, which I meet now for the first 

 time, raises questions which have a decided bearing on our ideas 

 regarding the growth of the freshwater algae generally. Here is a 

 plant whose cells can develop from 22 x 7 to 1020 x 140 /x (Ber- 

 nard gives 25 X 8 to 2000 x 220 /x), while at the same time the 

 endoehrome twice entirely changes its disposition. Judged by this 

 standard, all the forms of Myxonema or Ulothrix resolve them- 

 selves easily into one species. If the Hydrodictyon cell and its 

 chloroplasts grow and develop, why not Clostermm or Gyrosigma f 



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