Bioluminescence in decapod Crustacea

Luminescence in decapod crustaceans may be of two kinds. Either a secretion is ejected into the surrounding water as a luminous cloud, or specific light organs, which may be internal or superficial, glow steadily (Balss, 1944). There may be more than 150 photophores in some species of decapod, and the number, position and development of these organs inSystellaspis debilisand species ofSergiahave been described by Coutière (1906), Kemp (1910a), Terao (1917) and Gordon (1935). The production of luminous clouds has been observed in the Oplophoridae, Pandalidae and Thalassocarididae of the Caridea, and in the Penaeidae of the Penaeidea (Table 1). Observations of the luminescence of specific light organs or tissues are much less numerous. Luminescence has been observed among the Oplophoridae from the photophores of species ofSystellaspisandOplophorusand from the liver ofHymenodora. The hepatic organs ofParapandalusof the Pandalidae have been seen to luminesce, and among the Penaeidea both the hepatic organs of Pesta ofSergestesand the superficial organs ofSergiahave been seen to emit light (for references see Table 1). Undoubted hepatic light organs also occur inChlorotocoidesandThalassocarisof the Thalassocarididae, and superficial organs inHymenopenaeus debilisof the Penaeidae. Additional organs of doubtful function which have been described as possible photophores occur on the chelae of the homolid crabHypsophrys, in the branchial chamber ofSergestes, the pleopods ofParapandalusand the uropods ofAcetes(Table 2). There are unconfirmed reports of luminescence in the eye ofPasiphaea etarda(Kiernik, 1908) and inPolycheles(Alcock, 1902) andLeptochela(Chace, 1940), neither of the latter two cases being ascribed to a particular organ, though 'a greasy glandular patch' near the oviduct was implicated inPolycheles.