 As in all Agnostina, "Agnostus" has two thorax segments.When Agnostina are enrolled, a tiny opening between the cephalon and the thorax becomes visible (the cephalothoracic aperture) that uniquely distinguishes this group from the Eodiscina.Two features shared with all Agnostoidea are that the basal glabellar lobes are anteriorly expanded, and that the frontal lobe of the central raised area of the cephalon (or glabella) is not laterally expanded compared to the backward lobe.