ANIMAL CAROTENOIDS 



This only applied when colours were not due to the presence of sym- 

 bionts. Well nourished animals which are red or black lose all their 

 colour when they are starved. Whether all the colour is due to caro- 

 tenoids is not clear ; it seems unlikely for H. circumcinta when fed 

 ostracods or red copepods became orange-red owing to the formation 

 of semi- crystalline granules of carotenoids ; when fed Daphnia spp. 

 (which apparently contained no carotenoids) they became reddish 

 brown but accumulated no carotenoids. According to Teissier ^ ^ Clava 

 squamata eggs contains a grey chromoprotein which liberates a caro- 

 tenoid during development. 



1-4 



1-2 



hO 



0-8 



0-6 



0-4 



0-2 







420 440 



460 



480 500 520 

 Wavelength (mfi) 



540 



560 



Fig. 22. — Actinioerythrln {from Fabre, R., and Lederer, E. {1934) Bull. Soc. Chim* 

 Biol., 16, 105), and Sulcatoxanthin {from Strair), H. H., Mann'mg, W. M., 

 and Hardin, G. {1944) Biol. Bull. Woods Hole, 86, 169). 



More recent work has been centred on the three varieties of Actinia 

 equina, the red, brown, and green forms. An orange carotenoid 

 was detected in the red and brown variants and a red one in the red 

 animals. ^ ^ Subsequent investigations of the red animals by Lederer ^ ^ 

 and by Fabre and Lederer ^ ^ revealed, apart from a- and ^-carotenes, a 

 red carotenoid ester actinioerythrin combined with a protein ; about 

 1 -5 mg. (30% yield) of this pigment was obtained from 30 specimens. 



157 



