Diagnosis. See Larsen (2005).
Remarks. Fourteen described species were recognized by Larsen (2005) and three more new species were described by BłaŻewicz-Paskowycz & Larsen (2005). The genus is distributed throughout the world’s oceans and several species ought to be discovered in Japanese waters, Japan Trench, and the Kurile-Kamchatka Trench.