Carotenoid pigments in the coxal gland of Limulus.

The coxal gland of Limulus polyphemus contains a high content of carotenoids. Values ranging from 25 to 226 microgram per gram of wet tissue were found. The corresponding average value for 21 animals was 111 microgram. Chromatographic separation reveals the presence of 7 to 8 components. Characterization and partial identification of these components has been made by the determination of RF values and absorption spectra. In some cases the alterations produced in these properties by borohydride reduction have also been presented. The brick-red color of this tissue reported by earlier investigators would appear to be largely due to its high content of carotenoids.