Knight-Jones, Phyllis. (1978). New Spirorbidae (Polychaeta: sedentaria) from the East Pacific, Atlantic, Indian and southern oceans. Zoological Journal of the Linnean Society, London. 64(3): 201-240.
Spirorbis bifurcatus, Spirorbis rothlisbergi, Spirorbis spatulatus, Pileolaria lateralis, Pileolaria marginata, Pileolaria spinifer, Pileolaria tiarata and Pileolaria potswaldi are described from California, Spirorbis strigatus from Madeira, Pileolaria dakarensis from W. Africa, Pileolaria (Duplicaria) zibrowii from Madagascar, Pileolaria alata and Pileolaria (Nidularia) nidica from Curacao, Pileolaria (Nidularia) palliata from S. Africa, Pileolaria (Jugaria) atlantica from north of the Azores, Romanchella bicava from Amsterdam Island, Romanchella pustulata from Chile and Helicosiphon platyspira from Marion Island. Of the new subgenera, Jugaria is proposed for forms having compound opercula (as in Pileolaria granulata L. and most Sinistrella species) and Nidularia for those with opercula that do not completely protect the embryos. Some of the Californian forms have probably resulted from sympatric speciation in both the genera concerned. The morphology and zoogeography of spirorbids suggest division into the subfamilies Spirorbinae, Circeinae, Pileolariinae, Januinae, Romanchellinae and Paralaeospirinae.
