Maskell. — On the Neiv Zealand Desmidieas. 247 



From the Sumner Koad, Lyttelton, and very rarely from the Cust Valley. 



P. jenneri, Ealfs. (E. XXXIII.) or 



P. brebissonii, Meneghini. (E. 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 

 tkwaitesii for it. If P. brebissonii always occurs in colonies in mucous 

 strata, then I have not seen it. 



Very rare, in any case. 



9. Triploceras, Bailey. 



I observe that Eabenhorst and other algologists place this genus, with 

 some of the Docidia, under Naegeli's genus Pleurotanium, so that probably 

 Bailey's name must be given up. 



T. tridentatum, mihi, var. cylindricum, var. nov. 



In vol. xiii. of the Trans., p. 311, 1 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 ditch, and also, rarely, from Hawke's Bay. 

 10. Clostermrrij Nitzsch. 



C. griffithii, Berkeley. 



Fig. 14. 



Fairly common. Length, from 110-160 fi. 



G. venus, Kiitzing. 



I see that Eabenhorst considers this as a separate species, though Ealfs 

 unites it to C. diancc. 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. (E. XXVIII.) 



Not uncommon. 



Distinguishable, especially from C. selenceum, mihi, by its thick rounded 

 ends and by a conspicuous median inflation of the inner margin. As to 

 this, see below, under C. selenceum, in Part II. of this Paper. 



11. Spirotsenia, Brebisson. 

 Sp. obscura, Ealfs. 



Very rare. 



This plant is subject to the same disadvantage as Sp. condensata. Its 

 distinguishing character is the spiral endochrome and this is quite destroyed 

 by all the preserving fluids which I have tried. 



12. Scenedesmus, Meyen. 



Eabenhorst relegates this genus to the Palmellacese but as other authors 

 include it among Desmidieas I leave it. 



