carotenoids 



Reproductive Organs 



Unesterified xanthophylls occur in the ova and ovaries of many fish 

 (Table 33). Emphasis should be laid on the fact that [3-carotene which 

 has rarely, if ever, been observed in other fish organs, is a universal 

 constituent of egg carotenoids, although it is always only a very minor 

 component. The complete absence of carotenoids from the milt 

 of the marine fish (Ammodytes tobianus^^ and Clupea harengus^^) 

 contrasts strongly with their relative abundance in the eggs. 



Quantitative Studies 



Little is known of the quantitative distribution of carotenoids in fish ; 

 the figures collected in Table 34, are all that are available. 



Table 34 

 Carotenoid Content of some Marine Fish 



1. Goodwin, T. W. (1948). Unpublished work. 



2. Young, R. T., and Fox, D. L. (1936), Biol. Bull., 71, 217. 



3. Sumner, F. B., and Fox, D. L. (1933), jf. Exp. Zool., 66, 263. 



4. Sumner, F. B., and Fox, D. L. (1935), Proc. Nat. Aacd. Set., Washington, 21, 330. 



5. Sumner, F. B., and Fox, D. L. (1935), jf. Exp. Zool., 71. 101. 



6. Kritzler, H., Fox, D. L., Hubbs, C. L., and Crane, S. C. (1950), Copeia, p. 125. 



Formation and Metabolism 



Although little work has been carried out on the formation of 

 piscine carotenoids, it seems reasonably certain that they are of alimen- 

 tary origin ; they are not, however, always stored unaltered. The work 

 of Sumner and Fox ^ ' on carotenoid formation in the Pacific killifish, 



194 



