Verrill, 1883
Description
Hormathiidae with the base sometimes forming a normal, flat, adherent disc but usually invaginated, forming a cup enclosing a ball of mud or sand. Column differentiated into scapus and scapulus, the former with solid tubercles and periderm, the latter with longitudinal ridges. Cinclides are absent. Tentacles hexamerously arranged, usually in five cycles; endocoelic tentacles and perhaps sometimes the exocoelic ones with solid mesogloeal swellings on their aboral sides at the base. Six pairs of mesenteries perfect and sterile, mesenteries equal in number proximally and distally, mesogloea of older mesenteries very thick. Sphincter muscle very strong, retractors diffuse.
Type-species: Actinauge longicornis (Verrill, 1882)