THE BIOLUMINESCENT ORGANS OF THE DEEP-SEA CEPHALOPOD VAMPYROTEUTHIS-INFERNALIS (CEPHALOPODA, VAMPYROMORPHA)

Vampyroteuthis infernalis Chun is the sole member of the cephalopod su bclass Vampyromorpha. The three putative types of photophore (fin base , dorsomedial or composite, and skin nodules) are described and it is concluded that the composite organ is not a light-emitting structure. It has structural similarities to an extra-ocular photoreceptor. The f in-base photophore is capable of being everted from the pigmented pit in which it is seated. Its surface bears chromatophores which may modu late the emission and the photocytes contain an extensive network of m icrotubular elements and proteoglycan particles. The reflector is form ed of a very thick layer of collagen fibrils in different orientations . The skin nodules are widely distributed over the animal. They have a collagenous reflector and core cells with structural similarities to those of the fin-base photocytes. The photocytes have no morphological links with those of octopods or decapods. The thick collagen reflecto r, and absence of the iridosomal platelets present in the other subcla sses, suggests an early separation of the Vampyromorpha from other col eoids.