34–36 segments; twelve pairs of elytrae, progressively increasing in length, followed by smaller foliaceous lamellae posteriorly; surface smooth. Anterior margin of first pair of elytrae with papillae or fimbriae; 4–15 papillae; lateral margins of elytrae 2–12 notched. Branchiae number 12 pairs (on segments 8, 10, 12 ... 22, 23, 25, 26, 27). Neuropodial ventral lamellae absent. Acicular neurochaetae absent on anterior segments; dorsal neurochaetae of posterior segments straight or slightly curved dorsally.