WoRMS note details

Small Orbiniidae with rounded prostomium, lacking obvious eyes. Postchaetal lobes present in both noto- and neuropodia. Branchiae start from chaetiger 6 or posterior. Notochaetae camerate capillaries only. Distinctive ‘‘swan-shaped’’ hooks in neuropodial position, starting from chaetiger 6 or posterior. Camerate capillaries also present in neuropodia. Aciculae absent. Pygidium with four tapered cirri. Nuchal organs and lateral organs present.
Kelaher, B.P. and Rouse, G.W. 2003. The role of colonization in determining spatial patterns of Proscoloplos bondi sp. nov. (Orbiniidae: Annelida) in coralline algal turf. Marine Biology (Berlin), 143(5):909-917