328 CAROTENOIDS OF UNCERTAIN STRUCTURE XIV 



reflected in the solubility in 65 % methanol. The pigment is insoluble in petroleum 

 ether, sparingly soluble in carbon disulphide and readily soluble in benzene and 

 ethanol. Sulcatoxanthin crystallises from a mixture of ether and petroleum 

 ether in deep scarlet-red needles which show no sharp melting point but sinter 

 at 110°, soften at 125° and have completely melted at 130°. The pigment is 

 decomposed by the action of alkali. Concentrated sulphuric acid produces a blue 

 colouration. 



Solvent: Absorption maxima: 



Carbon disulphide 516 482 (450) m/j. 



21. GLYCYMERIN 



This carotenoid was isolated by Lederer^^ and by Fabre and Lederer''*' 

 from the sexual organs of Pedunculus glycymeris shells. On working up a larger 

 quantity of shells, glycymerin could no longer by obtained'^, a mixture of 

 several phytoxanthins being found instead. As the isolation of the pigment 

 could not be repeated and as Lederer himself obtained a very small quantity 

 which he did not consider as pure, the existence of this pigment must be 

 regarded as doubtful. Glycymerin crystallises in irregular brown-violet crystal 

 aggregates, m.p. 148-153°. It is almost insoluble in petroleum ether, but fairly 

 readily soluble in methanol. In carbon disulphide solution the pigment exhibits a 

 single absorption band at 495 m/ii. It exhibited no acidic properties, thus 

 differing from astacene. It is believed that the pigment occurs partly esterified 

 in the shell. 



Glycymerin has also been observed in the coat of Pedunculus glycymeris 

 and in the liver of Mytilus edulis^^' '". 



22. CYNTHIAXANTHIN 



In the course of his investigations of the pigments of different species of 

 ascidiae, Lederer found besides astacene, a new pigment, for which he proposed 

 the name cynthiaxanthin, in Halocynthia pipillosa''^. The same source was later 

 examined by Karrer and Solmssen'^^, but no cynthiaxanthin was obtained. 



In some respects cynthiaxanthin possesses properties very similar to those 

 of zeaxanthin. Chromatography of a mixture of the two pigments, however, 

 gives rise to two zones, the lower of which contains cynthiaxanthin. It is 

 therefore improbable that the two pigments are identical. Cynthiaxanthin also 

 differs in chromatographic properties from pectenoxanthin, since pecteno- 

 xanthin is adsorbed above zeaxanthin on calcium carbonate. 



For the isolation of cynthiaxanthin, the animals (15 specimens weighing 120 g) 

 are dissected and extracted with acetone. The pigments are transferred to petroleum 



References p. 341-343. 



