ABYSSAL BENTHAL AND PELAGIAL 



257 



fishes) have luminescent organs, which are absent in the few coastal 

 forms. Many luminescent cephalopods and fishes maintain themselves 

 in the transition zone between the lighted and the abyssal pelagial. 



Fig. 67.— Light organs of deep-sea animals: a, of a fish (Argyropelecus affinis) ; 

 b, of a schizopod crustacean (Nematoscelis mantis); and c, of an octopod 

 (Abraliopsis morisii) . Light cells stippled; reflector lined, backed by a pigmented 

 layer, black. A lens of varying structure in front of the light cells, made up of 

 cells in a, homogeneous in b, fibrillous in c; b, with an afferent nerve, n. lac, 

 lacunae, a after Brauer; b and c after Chun. 



What may be the function of this bioluminescence? The attraction 

 of prey must be considered as the primary possibility in the benthic 



