Distribution: Arctic to Antarctic. Body attenuated posteriorly. Anal fin and second dorsal confluent with tail. True fin spines lacking. Leading dorsal fin ray may be spinous. Usually with chin barbel. Pelvic fin insertion more or less thoracic. Pelvic fin rays 5-17; lacking in Macrouroides. No caudal fin, except in one species. Scales small. Light organ, if present, underneath skin along midline of abdomen with opening just before anus. Branchiostegal rays 6-8. Abdominal vertebrae 10-16. Maximum length usually 0.8 m. Mostly benthopelagic, occurring from 200-2000 m.