BY G. I. PLAYFAIR. 99 



main radiating chloroplasts each containing a pyrenoid, but 

 besides these there are 10-15 very narrow radiating laminae with- 

 out pyrenoids. A specimen was noted with the central pyrenoid 

 divided into three. (PL iii., f.2). 



Penium globosum var, Wollei (W.&G. S. West) mihi, f. maxima. 



Long. 70, ]at. 54 ^. 



Lismore(12). Cum priori. (PI. iii., f.3). 



Cf. Cos. globosum var. Wollei f. major G. S. West, I.e., p. 118, 

 P1.7, f.lO, with which it is practically identical, but half as large 

 again. The naming of this form affords an example of the diffi- 

 culties arising from the present system of nomenclature, and the 

 absolute impossibility of making the latter the expression of 

 observed biological facts. When any Penium of the Dysphiiic- 

 tium type undergoes rapidly repeated mitosis, the nascent semi- 

 cells have (in the short interval between one cell-division and 

 another) no time to attain their full proportions; the resulting 

 Penium-CQ\\s tend, therefore, more and more to become globose in 

 shape, the diameter remaining practically unchanged. Cos. 

 globosum Buln., is such a form, probably (diam. 22-25 /x, Monog., 

 iii., p. 27) the shortened form of Pen. polyiiio^ylmm (diam. 21-28/x, 

 Monog., i., p.91) or some other Penium. Cos. globosum var. 

 Wollei f. major G. S. West, (diam. 37-39 /x) I.e., is certainly a 

 diminished Pen. australe (diam. 36-38 /x) type, just as my f. 

 maxima (supra) is of P. australe f. crassior G.S.W. I find it so 

 in this gathering (12), and if the notes by G. S. West, 1 c, p. 11 8, 

 on Cos. globosum be compared with those, p. 108, on P. australe^ 

 it will be seen that, in the case of Victoria Nyanza at least, the 

 specimens of both were found in the same gatherings : — Bukoba 

 (20 Apr., 1905; lSro.251 and No.618). Cos. globosum is not really 

 a species at all, but merely a mixture of degenerate forms of 

 various " species " of Peniiwi, brought together under one name 

 on account of a similarity of shape. But it would be unreason- 

 able to make such a distinct form as P. australe a variation of 

 Cos. globosum (which has priority) although they are biologically 

 connected. There is nothing left, therefore, but to accept Cos. 

 globosum as a species, well knowing it to be a mass of contradic 



