This paper presents the results of a comparative study of five osteological complexes, the infraorbital bones, branchial arches, urohyal bone, interdigitation of the median fins, and the caudal fin skeleton, of some members of the fish family Tripterygiidae. Osteological characters that may prove valuable for taxonomic purposes are described, and on the basis of the material handled, their use to separate species within the family is discussed. Several formulae were developed for the distribution of the osteological complexes of the dorsal fin, dorsal and ventral caudal procurrent ray distribution, and caudal fin in the different tripterygiid species studied.
