CAROTENOIDS 



ethanol petroleum ether partition, was obtained. This is in contrast 

 to the typical crustacean complex which generally contains only 

 astaxanthin. The pigment complex from embryonic P. canalicuata 

 fixed in formol shows a single absorption band at 550 mfj,. The livers 

 of both newly born larvae and adults contain carotenes. It is interesting 

 to note that only Pila which lay eggs out of water produce pigmented 

 eggs, eggs which are buried are unpigmented. The former varieties 

 occur in the New World and the latter in India. It would be interesting 

 to know if the " unpigmented " forms were completely devoid of 

 carotenoids. 



VERTEBRATES (FISH) 



The difference between the carotenoids of marine and fresh water 

 fish is slight. Fresh water species are known which contain lutein 

 (xanthophyll), astaxanthin, and the '* taraxanthin-like " carotenoid 

 either singly or together. A possible difference is the more widespread 

 distribution of lutein (xanthophyll) in fresh water fish, but the " sam- 

 ple " of species so far examined is not sufficiently large to say whether 

 this is definitely so. 



Table 35 

 Carotenoid Distribution in the Brown Trout {Salmo Trutta)* 



* From Steven, D. M. (1948), J. exp. Biol., 25, 369. 

 t Values for S. irideus eggs.^^'^ 

 (a) Mostly P-carotene. (b) Mostly lutein (xanthophyll). 



202 



