Body rotund, can be inflated; head wide and blunt; eyes large; nasal organ an open pitted cup (in juveniles a tentacle with 2 openings); teeth fused into a strong, parrot-like beak that lacks a front groove, large, opens widely at front; gill opening a vertical slit before pectoral base; pectorals large; fins without spines; no pelvic fins; dorsal rays 12-14; anal rays 11-14; pectoral rays 19-22; body and head covered with numerous short (< eye), fixed, 3-4 rooted spines that are triangular and flattened in cross-section, and, in some cases reduced to plates under skin, ~ 8-10 in an approximate row from snout to dorsal fin; top of tail base with 1-2 spines; tail fin with 10 rays.
Grey on back grading to whitish ventrally; scattered black spots on head, body, and median fins; also several diffuse, dusky brown bars on head and body.
Size: grows to about 75 cm; the young lead a pelagic existence until about 20 cm.
Inhabits coral and rocky reefs, but also trawled on soft bottoms.
Depth: 1-141 m.
Circumtropical and with a largely temperate distribution; California to the Baja, and the southwest and central eastern Gulf of California to Chile, and all the oceanic islands except Clipperton.