Barbels and related muscles in Mullidae (Perciformes) and Polymixiidae (Polymixiiformes)

Barbels of the Mullidae and Polymixiidae were observed osteologically and m yologically. They were considered to be derived from branchiostegal rays. F our muscles, the extensor tentaculi, retractor tentaculi, and two sections of rotator tentaculi, were related to the barbels in both families. These m uscles originate from almost all the hyoid bones in mullids, whereas they o riginate only from the ventral hypohyal and fifth branchiostegal ray in pol ymixiids. In addition, each muscle related to the barbel of the former is i ndependent from others, but that of the latter is interconnected. These mus cular differences indicate that the barbels occurring in the two families a re nonhomologous.