CAROTENOIDS OF CAVERNICOLOUS CRAYFISH.

Small amounts of beta-carotene and lutein were found in Orconectes pellucidus pellucidus. Cambarus bartonii tenebrosus from the same cave contained much less carotenoid than surface crayfish. Astaxanthin, the principal carotenoid of most Crustacea, was absent from O. p. pellucidus, but accounted for 83 percent of the carotenoid of C. b. tenebrosus. These findings support other observations that pigmentation is dependent on the amount of carotenoid in the diet rather than on the presence of light. Furthermore, they suggest that O. p. pellucidus has lost or has never developed the ability to oxidize dietary carotenoids.