[1] They are bottom-dwelling cartilaginous fishes with large, rounded pectoral fin discs and long tails.

They have oval, rounded, or shovel-shaped pectoral discs and stout tails of equal or longer length.

The snout is moderately elongated, rounded, or rounded-angular, differing from the narkids in being supported by broad rostral cartilages.

The mouth is straight, with stout, elongated, and highly protrusible jaws and a prominent groove around its periphery.

[3] Numbfishes are slow-swimming bottom-dwellers that feed on small fishes and invertebrates off the bottom; their protrusible jaws aid in removing prey from the substrate.