FRESHWATER ALG.E. 



B. SYSTEMATIC ENUMERATION OF THE SPECIES OBSEEVED. 



ISOKONT^B. 



CIILAMYDOMONADACE.E. 

 Genus CHLAMYDOMONAS Ehrcnb.* 



1. CHLAMYDOMONAS SUBCAUDATA. 

 (PI. I, figs. 1-14 and 20.)f 



Chlamydomonas subcaudata Wille, "Algol. Notizcn," xi., Nyt Mag. f. Naturvidenskab, Ixi. (1903), 

 pp. 118-120, Tab. III., figs. 12-18. 



Long. cell. = 13-20 /x; lat. cell. = 7-14/x; diam. cyst. = 11-17 M aut 17-18/* 

 X 15-16 p.. 



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



This species was abundant in the above habitat together with Chlamydomonas 

 intermedia and C. ehrenbergi ; it is also recorded together with the first-named 

 species by Messrs. W. and G. S. West from Pony Lake (op. cit., p. 274). A 

 similar and closely allied species, C. caudata Wille, was abundant in material 

 collected from a pond in the South Orkneys (of. Fritsch, op. cit, p. 322). These 

 two species have, as far as I am aware, hitherto only been recorded from slightly 

 brackish ponds not far above high-tide level at Aalesund in Norway (Wille, op. 

 cit., pp. 118 and 119), so that their occurrence in temperate and tropical waters 

 still remains to be established. It is scarcely probable that they are restricted to 

 the cold regions of the earth. 



The dimensions above given for C. subcaudata are appreciably smaller than 

 those given by Messrs. W. and G. S. West, although both sets of measurements 

 are almost included in the extremes given by Wille (viz., 15-39 M long, 8-18 /A 

 broad). The marked difference in size of the individuals seen by Messrs. West 

 and myself indicates the occurrence of a large and small form of the species. 



With regard to the general characters of C. subcaudata there is not much 

 to add to previous descriptions. The cell-membrane was always separated by a 

 narrow space from the contents (figs. 1-5), but was not quite as prominently 

 thickened as Wille describes it. In the majority of the individuals the posterior 



* In material from the Gap pond, Winter Harbour, Po7meZZa-stages, looking like those of a Chlamydomonas, 

 were found on the surface of the Phormidium-sheet,a ; they could not be further determined. Cells oval or circular 

 with a pyrenoid, about 8-9 /j. broad ; mucilage hyaline, not stratified. 



t Nearly all the illustrations in this paper are the work of my wife. 



VOL. vi. H 



