PLATE XXIV 



FIGURES 1-2. Ulothrix cequalis Kiitz. x 500. 



FIGURES 3-4. Ulothrix cequalis Kiitz. forma, x 500. 



FIGURES 5-7. Ulothrix tenerrima Kiitz. forma untarctica. 5 and 6, x 500 ; 7, 



x 1000. py, pyrenoid. 

 FIGURES 8-9. Prasiola crispa (Lightf.) Menegh. 8, thallus, natural size.- 9, cells of 



small portion of thallus, x 500. 

 FIGURES 10-11. Prasiola antarctica Kiitz. 10, thalli, natural size; 11, cells of 



small portion of thallus, x 500. 

 FIGURES 12-14. Prasiola crispa (Lightf.) Menegh. Hormidium- stage, from vicinity 



of Cape Royds. x 500. 



FIGURES 15-18. Prasiola crispa var. aspera var. n. x 500. 

 FIGURES 19-24. Chlamydomonas intermedia Chodat forma antarctica. x 500. py, 



pyrenoid ; st, pigment spot. 23 and 24 show stages of division. 



FIGURES 25-29. Chlamydomonas subcaudata Wille. x 500 n, nucleus; py, pyre- 

 noid ; st, pigment spot. 28 and 29 show stages of division. 

 FIGURES 30-39. Pleurococcus dissectus (Kiitz.) Nag. x 500. 

 FIGURES 40^14. Pleurococcus frigidus sp. n. x 500 n, nucleus; py, pyrenoid; 



s, small granules of starch. 

 FIGURES 45-46. Pleurococcus pachydermusLagerli. x 500. n, nucleus ; py, pyrenoid. 



46 shows escape of eight daughter- cells (gonidia) from old mother- cell. 

 FIGURES 47-48. Pleurococcus pachydermus forma stipitata. x 500. 

 FIGURES 49-51. Pleurococcus antarcticus sp. n. x 500. ol, globules of fatty oil. 

 FIGURES 52-54. Pleurococcus antarcticus forma robusta. x 500. 



