General description: 

Frontal wall umbonuloid. Orifice with a broad distal shelf extending below the operculum, and prominent denticles on the proximal rim. Oral spines present. Avicularia typically paired, lateral. Basal pore-chambers present. Embryos brooded in hyperstomial ovicells.

(Hayward and Ryland, 1999)

Taxonomic name: 
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith