The spionid genera
Aonidella,
Laonice, and
Spiophanes are reviewed, with emphasis on material examined from deep water in the western north Atlantic. The type specimens of
A. dayi are reported and described for the first time, and the authorship of this genus is discussed. Two new deep-water species, belonging to the genera
Laonice and
Spiophanes, are described. A total of 19 species of
Laonice and 12 species of
Spiophanes are recognized and the taxonomic characteristics of these species are presented.