6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 92 



tliccoides in the culture kept in continuous darkness, and Chlorella 

 vulgaris in the culture kept in intermittent light. 



Two varieties, Scencdesmus qiiadricauda and Coccomyxa viridis, 

 were all slightly oti'-color, being a more or less pale or mottled green. 

 Cystococcus irregularis cultures in treatments 2, 6, and 7 were also 

 off-color. 



Cystococcus irregularis had green colonies in treatments i, 5, 8, 

 3, 4, and 9. 



Coccomyxa simplex retained chlorophyll in treatments i, 5, 8, 3, 

 and 2. At the end of 30 days all the cultures had been equally green. 



Haematococcus pliivialis was green only in treatments i, 5, and 8. 

 At the end of the 30-day period it had also been green in 4, 5, and 6. 



Scencdesmus qiiadricauda formed a green culture in intermittent 

 light. 



Stichococcus bacillaris was greenest in 3, 4, and 9 at the end of 

 60 days ; at the end of 30 days the cultures in 4, 5, and 6 were a 

 little greener than those in the other six treatments. 



DECOLORATION AT THE END OF 6o DAYS 



Decoloration was evident in all the cultures of Chlorella vulgaris 

 var. ; in Chlorella vulgaris in 3, 4, and 9 and in 2, 6, and 7 ; in Coc- 

 comyxa simplex in 4, 9, 6 ; in Palmellococcus protothecoides; and in 

 Cystococcus cohaerens in i, 8, 4, 9, 2, 6, and 7. Decoloration (rose 

 color) was beginning to appear in Palmellococcus variegatus under 

 conditions 8, 3, 9, 2, 6, and 7 ; and in Coccomyxa simplex in 7. 



CAROTIN FORMATION 



Five of the 18 algae formed carotin. Chlorella vulgaris and Scenc- 

 desmus Uavescens had orange-colored colonies in all the treatments. 

 The greatest amount of carotin was formed for Chlorella vulgaris in 

 intermittent light and for Scenedesmus Uavescens in intermittent light 

 and in continuous light. Beads of carotin were also formed for 

 Chlorella vtdgaris var. in i, 8, 3, 4, 2, 6, and 7: for Palmellococcus 

 variegatus in i, 5, 3, 4, and 2; and for Palmellococcus protothecoides 

 in 4. 



HAEMATOCHROME 



Haematochrome was formed in Haematococcus pluvialis in 2, 6, 

 7, 4, and 9. The greatest amount was in treatment 2, the culture kept 

 in intermittent light the first month and in continuous light the second 

 month. 



