The type and 5 additional species of Cordania, from the Lower Devonian of Quebec, Maine, New York, Tennessee, and Oklahoma, are described. Facial sutures are present, the anterior branches widely divergent; 9 thoracic segments. Mystrocephala n. gen. (type species C. pulchra Cooper and Cloud) includes Lower and Middle Devonian species differing from Cordania in that cheek and preglabellar field are concave distally and lack the convex border; pygidium has prominent posterior pleural bands extending to margin. The 2 genera are placed in Brachymetopidae, and a new diagnosis of that family given. Two species from Maine which occur with Cordania macrobius (Billings) are described: Bojoscutellum? pompilius (Billings), a scutelluid of uncertain generic affinities, and Astycoryphe? junius (Billings), a proetid with a weakly developed tropidium and Astycoryphe-like pygidium.