Somewhat indistinctly separated from the nominal subgenus, but thoracic neuropodia WITHOUT postsetal
papilla in middle of lobe, as against with single postsetal papilla in middle of lobe, with or without 1-2 additional papillae in lower part.
Pettibone, Marian H. (1957). North American genera of the family Orbiniidae (Annelida: Polychaeta), with descriptions of new species. Journal of the Washington Academy of Sciences. 47(5): 159-167. available online athttp://biodiversitylibrary.org/page/39753529 Available for editors [request]