10 F. E. FRITSCH. 



aii extreme case is shown in fig. 18. The stigma, however, was the most variable 

 feature of all; iu shape it was generally elongated and somewhat curved (figs. 15, 

 18), but occasionally it was almost round or oval (figs. 1G, 17) ; it was generally 

 situated in the back half of the cell, slightly in front of the pyrenoid (fig. 15), 

 but this position was by no means constant, and in some of the individuals it 

 was found quite close to the front end (fig. 18) or even (though rarely) quite near 

 the back end of the cell (fig. 17). In a number of individuals, moreover, more 

 than one stigma (up to three) was apparent, the respective stigmata either being close 

 together or somewhat removed from one another (figs. 17, 18). 



Messrs. West refer their C. intermedia to a forma antarctica (" forma minor, 

 stigmata juxta pyrenoidem "). The individuals from Cape Adare were even slightly 

 smaller than those recorded by these authorities, and in this respect they agree with 

 f. antarctica, but the position of the stigma, as above mentioned, was rather variable 

 and by no means always adjacent to the pyrenoid. 



3. CHLAMYDOMONAS EHRENBERGI. 

 (PL I., fig. 19.) 



Chlftmydomonas ehrenlergii Gorosch., Beitr. z. Morph. u. Systematik d. Chlamydornonaden, Bull. Soc. 

 Imp. d. Naturalistes de Moscou, 1891, pp. 128-131, Tab. III., figs. 10-25 ; Wille, op. fit., 

 pp. 123-124, Tab. IV., fig. 18. 



Long. cell. = 14-22 /LI; lat. cell. = 10-17 '5 [i. 



Hab. Pond some distance behind hut, Cape Adare, January 9th, 1902. 



This form is readily distinguished from C. intermedia Chod. by the shape of the 

 cells, which are ovoid and bluntly pointed at the front end ; the greatest width of the 

 cell is about one-third of the way from the back end. It was a rare form, far less 

 abundant than the two previous species.* 



Genus CHLOROMONAS Gobi. 

 4. CHLOROMONAS ALPINA. 



(PL I., figs. 21-25.) 

 Chloromonas alpina Wille, op. cit., pp. 122-124 and 152, Tab. III., figs. 24-34. 



Long. cell. = 10-11 /* ; lat. cell. = 6-8 p. 



Hal. In freshwater ice under boulder, Cape Adare, January 9th, 1902. 



This species appears previously only to have been recorded by Wille from 



* A species of Chlamydomonas was also observed in a sample from the ice, McMurdo Bay, September 13th, 

 1902, but the material was too scanty and the preservation too bad to admit of its determination. 



