CAROTENOIDS 



ANNELIDA 



Lonnberg*''^ has demonstrated the presence of carotenoids in the 

 skin of a number of polychaete worms. (Table 27.) 



MacMunn 2 8 observed a carotenoid, hidden from view beneath the 

 superficial melanin layer of the integument, in the black Arenicola 

 piscatorum. 



The polychaete Thoracophelia mucronata is the only worm for which 

 quantitative data have been recorded. ^ » It contains 0-38 mg. per lOOg. 

 of carotenes but is completely devoid of xanthophylls. In this 

 respect it differs from most marine invertebrates. Its diet is sand on 

 which is adsorbed marine detritus. The detritus contains both p- 

 carotene and xanthophylls but, as just stated, the worms accumulate 

 only p-carotene. The fate of the ingested xanthophylls is still doubtful, 

 for they are not excreted in the faeces ; they may be destroyed in the 

 lumen before they have the opportunity to be absorbed, or they may 

 be absorbed as such and then either completely oxidized or con- 

 verted into the yellow coloured, blue fluorescent chromolipids which 

 are stored in considerable quantities, but which are not carotenoids. * "^ 



PL A T Y HELM IN THES 



Francotte^'^ states that the colours of certain Polycladia (class 

 Turbellaria) are caused by carotenoids obtained from the Ascidia on 

 which they live. 



ASCHELMINTHES 



Lonnberg *' 1 '^ has noted the presence of carotenoids in a number 

 of Nemerteans (see Table 27). 



SIPUNCULOIDA 



Krukenberg ' ^^ reported the presence of a carotenoid in the digestive 

 juice of Siphonostoma diplochaitos and Lonnberg found carotene in 

 Phascolosoma elongatum. 



PRIAPULIA 



The zephyrean, Priapulus caudatuSy contains carotenoids.*-^* 



BRACHIPODA 



Carotene has been found in Crania anomala and Terebratulina caput 

 serpentis. 



166 



