Defining Characters: arrangment of Pharyngobranchial elements: PB2 and PB3 diverge posteriorly and expamded uncinate process of EB 2 contacts PB3 and provides structural bridge.

Membership: diverse array of shallow water and deep sea marine fishes, both benthic and mesopelagic. Less than 200 species. in twelve families. Icluding: deep sea tripod fishes, bombay duck, shallow water forms include family Synodontidae, Lizard fishes in western north atlantic three or four of the 25 species  are found.