by A. P. Andriashev and V.V Fedorov
Body elongate or very elongate. A single pair of nostrils; mouth terminal, subterminal or inferior. Dorsal fin very long, confluent with caudal fin; pectoral fins usually well developed; pelvic fins either very short and jugular, or absent; anal fin long, confluent with caudal fin, which is reduced. Scales very small, embedded, sometimes absent; lateral line without pores, composed of free neuromasts, often indistinct. No swimbladder. Vertebrae 62-150.
Benthic in littoral zone down to considerable depths in cold and temperate waters of both hemispheres. Feed on small bottom invertebrates. Eggs few and large, demersal (rarely viviparous).
Genera about 50; in Clofnam area 7.