The Rudder-fishes
HERBIVOROUS fishes, with incisors only in the front of the jaws; body oblong or elevated, with moderate or small scales; mouth moderate, with incisor-like teeth in front; no molars; premaxillaries moderately protractile; pseudobranchiae well developed; opercles entire; gill-membranes separate, free from the isthmus; dorsal fin continuous or divided, with 10 to 15 rather strong spines; anal with 3 spines.