(Family and Genus): All fins without spine. Dorsal fin located above anal fin at the rear part of body, no semi-isolated spine in front of the fins. Pelvic fin abdominal, with 5 soft rays. Teeth of jaws minute in bands. Posterior margin of upper jaw not remarkebly extending beyond eye. Side of body without scales, skin smooth. No tubular lateral line. (Species):No spine above eye.
Distribution:
Deep sea of Atlantic, Indian, and Pacific oceans.
Remarks:
This family consists of 1 genus and 2 species. Other families of Cetomimiformes are distinguishable from this family by following characters:Cetomimidae have upper jaw which posterior margin markedly extending beyond eye and no pelvic fin; Barbourisiidae have rough skin minute spines grown. Another species of this genus, R. bicolor, is distinguishable from this species by bearing a spine derecting anteriorly above eye. (Uyeno and Sato)