Paraustrorhynchusgen.n.,P. pacificussp.n. (California),Antiboreorhynchus novzelaesp.n. (New Zealand) andGyratrix proaviformissp.n. (Oregon) are described as new taxa. Additional notes are given onGyratrix hermaphroditusEhrbg. (new localities on the N. American Pacific coast),Scanorhynchus forcipatusKarling (new locality in California),Paraustrorhynchus elixus(Marcus) comb.n. andAlcha evelinaeMarcus (new localities in California). The taxonomy of the genera and species is discussed. Viewpoints are presented on evolutionary trends and homologous atrial organs in the family Polycystididae.