218 PROCEEDINGS OF THE ACADEMY OF [1896. 



US to conclude that in it we find a connecting link between the 

 crystallizing carotin of red flowers and fruits and the amorphous 

 resin-like xanthin of yellow flowers, and these observations tend to 

 confirm Courchet's views that the pigments of yellow and red 

 chromatophores having the property of turnins: blue or green with 

 sulphuric acid, thus distinguished from all other pigments, repre- 

 sent a group of closely related compounds- whose composition cer- 

 tainly demands further investigation.^ 



^ Courchet, Eecherches sur les chromoleucites. Annales de Sc. Nat, Bot. VII 

 Ser. VII, 1888, p. 291. 



^ The coloring matter described in this paper is also remarkable for its resis- 

 tance to the action of alkalies. Boiling with potassium hydroxide does not de- 

 compose it. 



