ANIMAL CAROTENOIDS 



liver of E. cirrosa, no carotenoids were detected. Specially significant 

 is their absence from the eggs of R. macrosoma and S. scandica. A 

 xanthophyll and a carotenoid-albumin have been reported in the 

 retinal rods of E. moschata but the evidence presented is not com- 

 pelling. '^ ^ Wagner and Vermeulen^^^ and Leong'^^ state that caro- 

 tenoids are absent from cuttle-fish. 



More recently Fox and Crane '^ have investigated the pigments 

 from two Pacific cephalopods, the two-spotted octopus, Paroctopus 

 btmaculatuSy and the common squid, Loligo opalescens. Carotenoids 

 occurred only in traces in the eyes of the squid, and this had been 

 previously noted by Wald ; " none or only "suspected" traces 

 occurred in other organs. In the octopus the liver and the ink were the 

 only tissues containing any carotenoids ; the liver contained (i-carotene 

 and free and esterified xanthophylls both of the neutral and acidic 

 type ; the distribution was similar in the ink except that no |3-carotene 

 was present. The chief carotenoid was lutein (xanthophyll) and the 

 acidic pigment appeared to be diflPerent from both metridin and 

 astaxanthin. Measured as lutein the carotenoid levels in the liver and 

 ink were 3-5 mg. per 100 g. and 0-55-0-70 mg. per 100 g. respectively ; 

 these levels dropped during starvation. 



The presence of carotenoids in the ink can promote much specula- 

 tion. As Fox and Crane point out, loss of carotenoids can take place in 

 many ways : sloughing of skin, growth and moult of feathers, discharge 

 of ear wax in cattle, and secretion from the femoral pits in iguanas, 

 but apart from the secretions from internal structures relating to 

 reproduction (eggs in many oviparous vertebrates and invertebrates, 

 and milk from mammary glands), no other such secretion of carotenoids 

 is known save that of the ink. 



GASTROPODA 



Lonnberg has detected varying amounts of carotenoid, in a number 

 of marine gastropods. The gonads of the limpets. Patella vulgata and 

 P. depressa, have been studied by Goodwin'* and Goodwin and 

 Taha. ' ^ 



Five carotenoids were identified : a- and ^-carotenes, echinenone, 

 cryptoxanthin, and zeaxanthin. All these occurred in both testes and 

 ovaries and in the same relative proportions, viz. : 1:5:3:3:3 

 respectively. Little variations in both total and relative amounts were 

 found in limpets collected at the same time in various parts of Great 

 Britain. No differences could be found between P. vulgata and P. 

 depressa. 



179 



