58 



mBgnesia„ They were not observed below the green zones when extracts 

 of the organisms were sorbed in magnesia colxjimnSo They resembled the 

 two principal xanthophyllSo 



Corresponding pigments from the several species of the Heterokontae 

 were shown to be identical by mixed adsorption, by spectral properties 

 and by color reactions with acid. 



In 1914.3 traces of a chlorophyll (chlorophyll e_) , with adsorption 

 maxima at 14.15 and 6514. fflA in methanol, were isolated from a natural 

 growth of Tribonema bombycinum- ^?°o In I9I4B the same or a similar chlo- 

 rophyll was found in a natural stand of Vaucheria hamata. This chloro- 

 phyll has not been observed in the small quantities of the species that 

 were cultured (Appendix VI) » VVhether or not it is a trace constituent 

 of the Heterokontae algae, a secondary product, or a pigment from algal 

 contamination has yet to be establishedo 



Pigments of the Chrysophyta of the Class Bacillariophyceae, Diatoms 



Several unidentified species of filamentous diatoms collected at 

 Palo Alto Yacht Harbor, at Half Moon Bay and at Oahu yielded the pig- 

 ments shown in Figure 111,6, namely, chlorophylls a and c, fucoxanthin 

 and its isomers, diadinoxanthin, diatoxanthin and /3-carotene plus or 



minus o(=caroteneo These are the same pigments previously isolated 



T 16 



from pure cultures or from unialgal cultures of four species * » 



Comparison of the pigments of the Heterokontae (Figure 111,3) 

 with those of the Bacillariophyceae (Figiare 111,6) reveals that 

 these two kinds of organisms differ with respect to the principal 

 xanthophylls and the minor chlorophyllo This difference corresponds 

 in magnitude to the pigment differences among the principal algal 



