CONCERNING THE PIGMENTS OF THE TWO-SPOTTED OCTOPUS AND THE OPALESCENT SQUID x DENIS L. FOX AND SHELDON C. CRANE (From the Scripps Institution of Oceanography, of the University of California, La Jolla, California} The majority of fishes and invertebrate species of the sea exhibit integumentary colors due either to melanin pigments or, especially in the invertebrates, to carotenoids. Carotenoids are often also relatively con-centrated in such tissues as the liver or digestive gland, and in eggs. Chromoproteins, flavines, purines, and certain more rare pigmentary compounds are discussed by numerous writers (e.g. Verne, 1926). This paper concerns the pigments encountered in various tissues of two cephalopods of Pacific waters, namely the two-spotted octopus, Paroctopus bimaculatus , and the common squid, Loligo opalescens. Cephalopods studied by Lonnberg (1935) and the two species investi-gated by us have revealed a striking general absence of carotenoids from the integument and gonads and only traces in the eyes, but there are con-siderable quantities of these yellow, orange, or red pigments in the "liver" ; of Paroctopus. Melanins characterize the ink of these mol-lusks, and are present also in the iris and skin. Octopods show rela-tively large quantities of melanin in their highly specialized chromato-phores, while certain squids exhibit very little in the integument, the pigment there often appearing light brown or reddish instead of grey or deep brown as in the former group. We encountered, in the pericardial glands of the octopus, small amounts of yellow flavines as well as a red water-soluble pigment of unknown identity in the kidneys. Lonnberg (op. cit.), making preliminary studies of the carotenoids of three cephalopods, reports lutein in the eyes of Sepiola scandica, Rossia macrosoma, and Eledoue cirrosa. He found no carotenoids in the eggs of Rossia or Sepiola, and only possible traces in the testes of Eledonc. Extracts of Rossia eggs, however, gave a strong color reaction with SbCl 3 , suggesting the possible presence of vitamin A or a similar com-1 Contributions from the Scripps Institution of Oceanography, New Series No. 154. 2 The term as employed here refers to the large red-brown, grey or greenish gland communicating by a pair of ducts with the alimentary canal at the junction of stomach and intestine. Actually the "liver" and "pancreas" are incorporated together, without a very sharp division, in the single gland. 284
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