CHAPTER VI 

 MARINE VERTEBRATES ; AMPfflBIANS : OCEAN BED 



PROTOCHORDATA 



TUNICATA 



The early work of Kruckenberg ^ and Lonnberg * had demonstrated 

 the presence of carotenoids in a number of tunicates {see Table 30), but 

 only four have been examined in any detail, and this examination has 

 been carried out by Lederer. ^.^ 



Halocynthia papulosa {Cynthia papulosa), Microcosmus sulcatuSy 

 Botryllus schlosseri, and Dendrodoa glossularia all contain considerable 

 amounts of xanthophylls but only very small amounts of a- and ^- 

 carotenes. H. papulosa^ which is dark red, contains both free astaxan- 

 thin and a unique xanthophyll, cynthiaxanthin, in both the tunic and 

 internal organs ; astaxanthin predominates. Cynthiaxanthin is of 

 unknown structure but has the following physical properties ; m.p. 

 188-190° ; XX ^^x. 517, 483, 451 m(x. (CS^) and 482 and 452 mjx. 

 (light petroleum) ; it gives no blue coloration with concentrated 

 hydrochloric acid. Karrer and Solmssen, ^ however, could not detect 

 cynthiaxanthin in their specimens of H. papulosa. The rose coloured 

 social tunicate D. glossularia contains principally esterified astaxanthin ; 

 15-20 mg. were obtained from 440 g. of animals. 



Closely related to H. papulosa is the violet M. sulcatus which contains 

 a complex mixture of carotenoids, mainly free xanthophylls, which 

 were very difficult to separate. The major xanthophyll was similar to 

 lutein (xanthophyll) but gave a blue colour with hydrochloric acid. 

 The carotenes detected were probably echinenone {see p. 163) and 

 a- carotene. 



The brown- red tunicate B. schlosseri contained a mixture from which 

 pectenoxanthin {see p. 175), capsanthin and capsorubin were isolated. 

 The presence of the latter two carotenoids was probably due to the fact 

 that the animals were obtained from a harbour into which pimento 

 pepper waste had been dumped ; Heilbron, Parry and Phipers «, 

 however, suggest that they might have been formed by oxidation of 

 fucoxanthin contained in the algal foodstuffs. 



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