MaskELL.—On the New Zealand Desmidiee. 247 
From the Sumner Road, Lyttelton, and very rarely from the Cust Valley. 
P. jenneri, Ralfs. (R. XX XIII.) or 
P. brebissonii, Meneghini. (R. XXV.) 
I have great doubts which of these two occur here, or indeed whether 
either has come under my observation. Possibly I have mistaken Cosmarium 
thwaitesii for it. If P. brebissonit always occurs in colonies in mucous 
strata, then I have not seen it. 
Very rare, in any case. 
9. Triploceras, Bailey. 
I observe that Rabenhorst and other algologists place this genus, with 
some of the Docidia, under Naegeli's genus Plewrotenium, so that probably 
Bailey’s name must be given up. 
T. tridentatum, mihi, var. cylindricum, var. nov. 
In vol. xiii. of the Trans., p. 811, I described a plant of this species with 
a rectangular section. The present variety is circular in section, and of a 
generally thicker form. Otherwise there seems to be no difference, and the 
two are found together. 
From the Bryndwr diteh, and also, rarely, from Hawke's Bay. 
10. Closterium, Nitzsch. 
C. griffithii, Berkeley. 
Fig. 14. 
Fairly common. Length, from 110-160 y. 
C. venus, Kiitzing. 
I see that Rabenhorst considers this as a separate species, though Ralfs 
unites it to C. diane. As far as I can make out, the main difference be- 
tween the two is that C. venus is the smaller. However, the dimensions 
appear to be constant. 
C. ehrenbergii, Meneghini. (R. XXVIII.) 
Not uncommon. 
Distinguishable, especially from C. seleneum, mihi, by its thick rounded 
ends and by a conspicuous median inflation of the inner margin. As to 
this, see below, under C. selenzum, in Part 1I. of this Paper. 
11. Spirotznia, Brébisson. 
Sp. obscura, Ralfs. 
Very rare. 
'This plant is subject to the same disadvantage as Sp. condensata. Its 
distinguishing eharaeter is the spiral endochrome and this is quite destroyed 
by all the preserving fluids which I have tried. 
12. Scenedesmus, Meyen. 
Rabenhorst relegates this genus to the Palmellacez but as other authors 
include it among Desmidies I leave it. : 
