They feed on a variety of small bony fishes and invertebrates; at least two species specialize on cephalopods.

The dorsal and pelvic fins, and the lower caudal lobe are strongly falchate.

Several fossil species are known, including H. curvatus and H. serra; in the Tertiary, this genus had a global distribution.

[2][3] This genus has a rounded or slightly pointed snout, short gill slits, and a broadly arched mouth.

The upper teeth have long cusps, and no toothless spaces occur at the jaw midlines.

The dorsal and pelvic fins and the lower caudal lobe are not falchate in shape.