Acrocirrus Grube and
Macrochaeta Grube (Polychaeta Sedentaria), comprising at present 14 species, are removed from the Cirratulidae and placed in a new family. The descriptions of the type species of the genera and of five other species are materially improved.
Acrocirrus trisectus and
Macrochaeta pege are newly described;
Acrocirrus heterochaetus okotensis Imajima is elevated to species rank. Diagnoses and records as well as keys for identification are given for all species of the family.
