; superorder Protacanthopterygii, order Salmoniformes)
A small family of deep-sea fish that have a single, soft-rayed, dorsal fin near the tail fin, above the anal fin. The eyes and mouth are rather large. The peculiar shoulder organ is typical of the family. It is a large, black sac opening to the exterior through a tube-like process above the pectoral fin. When the sac contents are released, a greenish glow appears beside the fish. Many species have a widespread distribution. There are about 17 species.
Subjects: Zoology and Animal Sciences.