CAROTENOIDS 



preponderate, whilst, as will become apparent as the chapter proceeds, 

 in most invertebrates xanthophylls preponderate. Suherites domnucula 

 and Ficulina ficus yield a complex mixture of hydrocarbons, containing 

 a-, [3-, and y-carotenes^ lycopene, and torulene.^ Karrer and Solmssen^ 

 isolated astaxanthin {see p. 168) {rom Axinella crista-galli and Drumm '> ® 

 and his colleagues a-, [3-, and y-carotene and a pigment probably 

 identical with echinenone (see p. 164), the characteristic carotenoid of 

 echinoderms, from the red sponge Hymeniacidon sanguinea ; astaxan- 

 thin was, however, not present. 



COELENTERATA 



Fox and Pantin^ have produced an authoritative review of all types 

 of pigments occurring in the coelenterata and the reader is referred to 

 this for detailed information. 



Carotenoids are the main source of colour in this family, and it was 

 in the siphonophore Velella spirans that the first carotenoid protein 

 complexes were noted, i*'-^^ As early as 1881 Merejkowski ^ '^ 

 recognised ** tetronerythrin " and " zooerythrin " in Actinia equina 

 {mesembryanthemum) Aiptasia spp., Cereactis spp., and various hydro- 

 zoa. Apart from a few observations by Schultze ^ ^ further reports were 

 lacking and in 1922 Palmer ^^ could say with some justification that 

 there was no definite evidence of carotenoids in coelenterates. Since 

 then interest has been stimulated and in a long series of papers, Lonn- 

 berg 1 ^> 1 ^ has at least indicated the presence of carotenoids in almost 

 every branch of the Coelenterata ; in a number of aloyanarians (first 

 noted by Studer^' in Eunicella verrucosa), in various actinarians, in 

 the madreporarian, Caryophyllia smithi, in the ceriantharian Cerianthus 

 lloydi, in the scyphozoan Lucernaria quadricornis, and in the hydroid 

 gymoblasts Tubularia larynx in Tubularia indivisa (previously noted in 

 the group by MacMunn^^) and by Teissier i* in Clava squamata. 

 Regarding the Calyptoblasts the position is less clear ; Lonnberg 

 could not detect carotenoids in clean Antennularia antennina and em- 

 phasised the necessity of removing diatoms from colonies before 

 examination. Similarly, Abeloos and Teissier ^^ did not find caroten- 

 oids in Sertularella, Aglaophenia, and Lafoea spp. ; their occurrence 

 has, however, been reported in Antennula,ria ramosa and A. antennina. '^ ^ 



Perhaps one of the most interesting problems of carotenoid bio- 

 chemistry in coelenterates is the relationship between the varied colours 

 which varieties of the same species can assume and their carotenoid 

 disposition. 



The pioneer in this field was Schultze ^ * who showed that in Hydra 

 species colours were a reflection of the nutritional state of the animals. 



156 



