136 BIOLOGY OF THE RICHMOND RIVER, 



Syn., Gleocapsa punctata Nag., Gatt. Einz. Alg., T. i., f.rG. 

 These are the younger stages of development of Cvdosphmrium, 

 Kiltzingiariurn. In gathering (16) there were quantities of them, 

 the growth from a single cell being easily seen (PI. vi., f.21). 

 This cell is indistinguishable from Merismopedia punctata (also 

 noted in the river), and I consider, therefore, that C aelosphcErium 

 is 3i fades of Merismopedia, with a globose coenobium instead of 

 a flat one. How this is accomplished (the plant still retaining 

 its division in one plane) is very simple. The four cells result- 

 ing from the division of the original cell in two directions, 

 arrange them at the angles of an imaginary tetraedron, and each 

 cell thenceforward divides regularly in its own plane. The same 

 two modes of development occur in Tetraedron lobulatum, where 

 both flat and tetraedral forms are produced by growth from the 

 same flat cell. 



CHYTRIDIACEi?^. 



Genus Trochisia Kiitz. 

 Trochisia hirta var. elliptica, n.var. 

 Cellulae irregulariter ellipticae. Cytoplasma hyalinum. 

 Long 58-60, lat. 36-40, spin. long, ad 12/x 

 Lismore, on decaying cells of Spirog. maxima (20). (PI. vii., 



f.i). 



Of. De Bary, Conj., '1\ i., f.6. This is a half-grown form of 

 Tr. hirta. 



Formae valde iMMATURiE. (PL vii., f.2). 



Cellulse minimae globosae, primum glabrae deinde minute den- 

 ticulatse. Cytoplasma hyalinum. 



Diam. cell. 8-1 4 />i, spin. long, ad 1 fi. 



Lismore, on decaying cells of Spirog. maxi7na{ 1 6); on decaying 

 specimens of Penium aicstt-ale and Doc. trahecula{Vl). 



Cf. Reinsch, De Spec, generibus, T.5d, f.iii. 3, whose figure 

 works out at diam. 20/x. On a single Spirogyra cell, 30 were 

 observed, each surrounded by the excavated (1), circular space 

 characteristic of Trochisia, in situ. Six were noted also on one 

 specimen of Pen australe. I have observed Tr. hirta also in 

 Eremosphcera viridis. Wille's excellent account and figures of a 



