274 W. AND G. S. WEST 



sample from Cape Adare, that there is no difference between P. antarctica and P. crispa. 

 Wille's figures show that the specimens he examined were ordinary forms of P. crispa, 

 but we fail to see how that in any way affects the specific distinctness of P. antarctica. 



VOLVOCACE.E 

 Genus CHLAMYDOMONAS Ehrenb. 



7 Chlamydomonas nivalis (Bauer) Wille 



"Alg. Notizen XI," Nyt Magazin f. Naturvidenskab, Bd. 41, Heft 1, 1903, 

 pp. 147-149, t. 3, f. 44, 45 ; t. 4, f. 25. Sphcerella nivalis (Bauer) Sommerfeld, 1824. 



Diam. cell. 19-23.5 ^ 



Hob. Blue Lake and Deep Lake. 



Only the resting stage of this Alga was observed. The brillant red cells, full of 

 fatty- oil reserve, occurred in small groups among Pleurococcus antarcticus forma robusta 

 in the stratum of Phormidium glaciate. 



8 Chlamydomonas subcaudata Wille 



I.e. p. 118, t. 3, f. 12-18. 



Long. cell. 31-34 /* ; kt. 16.6-18 /u. (PI. XXIV, Figs. 25-29) 



Hob. Pony Lake. 



This rather large species of the genus was fairly common amongst Chlamydomonas 

 intermedia forma antarctica. It possesses very distinctive characters, and the 

 Antarctic form scarcely differs in any way from that originally described by Wille 

 from Aalesund. The protoplast fully occupied the middle portion of the cell, but 

 both in front and behind it did not extend close up to the cell- wall. The posterior 

 extension of the cell- wall was generally acute, but no specimens were seen in which 

 it was subcaudate as in Wille's Fig. 12. Nearly all the cells were very slightly 

 asymmetrical about the longitudinal axis. 



The chloroplast is massive, with a very large pyrenoid in its hinder half. The 

 pyrenoid is in the median line and immediately in front of it is the nucleus. The 

 nucleus is thus slightly nearer the centre of the cell than in Wille's specimens. (Of. 

 Wille's Figs. 12-15.) In all the specimens seen the chloroplast appeared to be finely 

 pitted, giving rise to flattened tooth-like marginal projections such as those figured 

 by Wille in his end view of the cell (Wille, Fig. 16), but in the Antarctic specimens it 

 was not possible to ascribe this appearance to longitudinal grooves. We would prefer, 

 however, not to press this point, as it is often difficult to clearly make out the finer 

 details of a chloroplast in preserved material. 



Many examples were in the process of formation of daughter- cells, four of which 

 were produced in the mother- cell. The division was evidently by two oblique planes 

 crossing each other almost at right angles. ( Vide PI. XXIV, Figs. 28, 29) 



