168 CAROTINOIDS AND RELATED PIGMENTS 



phylloid, is stated to be the liver pigment of Crustacea and other 

 arthropods (spiders, insects). 



It seems to be apparent from even these meager studies that the 

 digestive organ, at least, of molluscs may contain a pigment which 

 may be either carotin or xanthophyll or a modification of one of the 

 carotinoids. 



Carotinoid in Worms 



Miss Newbigin (1898) has given an excellent summary of the 

 brilliant colors, both pigmental and structural, shown by the various 

 species of worms. It is evident that many types of pigments are pres- 

 ent. Carotinoid-like pigments, however, are not entirely absent, if 

 one is to judge from the observations of the older investigators. 

 These observations, unfortunately, have been confined to only a few 

 species so that it is not possible to decide how widely distributed these 

 chromolipoids may be among the worms. 



Krukenbcrg (1882h) found a rhodophane-like lipochrome in the pure 

 uncontaminated digestive juice of Siphonostoma diploehditos. He 

 (1882i) has also described a lipochrome in the cuticular skeleton of 

 the Polyzoa, Bugula neritina, whose spectrum is identical with that 

 of carotin. The pigment is not, however, the chief one of this species. 

 According to MacMunn (1890) the orange-red color of two other 

 species of this class of worms, namely, Lepralia foliacea and Flustra 

 foliacea, is due to a rhodophane-like lipochrome. 



Among the Chaetopods, or segmented bristle worms, MacMunn 

 (1890) found several species among the Polychaetes which appar- 

 ently contain carotinoids. In Arenicola piscatorium, a black worm, 

 the intestine was found to be covered with an orange-colored glandu- 

 lar tissue. The pigment could be extracted with the fat solvents and 

 alcohol, and the extracts showed two, possibly three bands in the 

 green and blue. The integument was found to contain the same pig- 

 ment masked by melanin. In a Terebella species the tentacles and 

 integument contained a lipochrome showing two absorption bands. A 

 like pigment was found in the integument of the species Cirratulus 

 tentaculatus and C. cirratus. Nereis virens, the common clam worm 

 of the northern seas, contained it also, but in smaller quantity. In 

 Polynoe spinifera most parts of the worm contained the same lipo- 

 chrome. 



These observations, while brief, point very strongly to the presence 

 of carotinoids in worms. Before passing to the sponges in which 



