In all, 15 species of amphinomid and euphrosinid polychaetes are reported from collections taken primarily by the U.S. Antarctic Research Program (USARP) sponsored cruises to Antarctic and Subantarctic waters. A new genus and nine new species are described as follows: Amphinomidae:
Chloeia australis; Euphrosinidae:
Euphrosine abyssalis,
E. antarctica,
E. armata,
E. echidna, and
E. monroi; and
Euphrosinopsis new genus:
Euphrosinopsis antipoda,
E. crassiseta, and
E. horsti. The amphinomid genus
Branchamphinome Hartman, 1967, the euphrosinid genera
Euphrosine Lamarck, 1818 and
Euphrosinella Detinova, 1985, and the species
Branchamphinome antarctica are emended; lectotypes and paralectotypes are designated for the latter species.
Pareurythoe chilensis (Kinberg, 1858) is newly reported from South Australia. Previous records and the endemicity of the order Amphinomida from Antarctica are discussed; a preliminary systematic scheme modified from Horst [1903] is given for all described species as
Euphrosine,
Euphrosinella, and
Euphrosinopsis; and a key to all known species of Antarctic amphinomid, euphrosinid, and spintherid polychaetes, considered valid, is also presented.