ANIMAL CAROTENOIDS 



an cver-estimate, for in the phase separation technique, echinenone is 

 epiphasic and remains with the carotenes. 



Manunta has reported the presence of carotenoids in the lungs, 

 mesentery, intestine and gonads of flolothuria forskali, H. tubulosa, 

 and H. polii. The greatest concentration exists in the gonads of the 

 first two species, whilst in H. polii, the intestine is the major site of 

 accumulation. 



Crinoidea 



Karrer and Solmssen^, in finding no detectable amounts of caroten- 

 oids in the sea lily Antedon rosacea, have confirmed the previous report 

 of Lederer. ^ Lonnberg, ^ however, has noted them in A. petasus. 



ECHINOIDEA 



This class has been investigated rather more fully than have those 

 just discussed.* It was from the gonads of Paracentrotus {Strongylocen- 

 trotus) lividus that Lederer ^ ^ obtained the pigment echinenone (Table 

 26 and Fig. 23). Echinenone also occurs in the gonads of Echinus 

 esculentus and Echinocardium cordatum and also in the perivisceral 

 fluid of the latter species. ^ ^^ 



It was at first thought that echinenone was characteristic of echinoids 

 but recently Goodwin and Taha^^^ have shown that, as suggested by 

 Lederer but rejected by Heilbron and Karrer ' ^, it is probably identical 

 with myxoxanthin isolated from Oscillatoria rubescens by Heilbron and 

 Lythgoe^^^ (see p. 136) and with aphanin obtained from Aphanizomenon 

 flos-aquae by Tischer ^ ®^ {see p. 136). It also occurs in the gonads of the 

 gastropods. Patella vulgata and P. depressa"^^ (see p. 179) and in the 

 sponge Hymeniacidon sanguineum''^^ (see ^. 156). It thus appears to 

 be widely distributed in algae and marine invertebrates and the 

 interesting biochemical problem of whether the animals obtain 

 echinenone directly from their algal food or make it by oxidizing a 

 pigment such as p-carotene, remains to be solved. 



Goodwin and Taha^'®^ consider the structure of echinenone to be 

 in all probability 4-keto-p-carotene : — 



Echinenone (probably) 



* See Table 27. 

 163 



