CAROTENOIDS 



Table 30. — Carotenoid Distribution in Tunicates 



REFERENCES TO TABLE 30. 



1. LONNBERG, E., and HellstrOm, H. (1931), Ark. Zool, 23A. No. 15. 



2. Lederer, E. (1934), C. r. Soc. bioL, 117, 1086. 



3. Karrer, p., and Solmssen, U. (1935), Helv. Chim, Acta, 18, 915. 



4. Lederer, E. (1938), Bull. Soc. Chim. Biol., 20, 567. 



Enteropneusta 



The only report is that of Lonnberg', in which the presence of a 

 xanthophyllic carotenoid is indicated in Harrimania kupferi. 



FISH 



Some of the brilHant skin colours of marine fish are due to carotenoids 

 which exist in the chromatophores. The carotenoids are almost 

 always entirely xanthophyllic and there is very little variation from 

 species to species. Either astaxanthin, or lutein (xanthophyll), or a 

 taraxanthin-like carotenoid or a mixture are the only pigments generally 

 present. According to Lonnberg**, fish fall roughly into two groups, 

 those containing lutein (xanthophyll) and those containing the taraxan- 

 thin-like carotenoid ; he appears to have overlooked the presence of 

 astaxanthin. Even with this small number of alternatives it is very 

 difficult to forecast the carotenoid make-up in any single member of a 

 species. A review of the biochemistry of fish carotenoids has recently 

 appeared. ^^ 



190 



