Figure 10. Achatella katharina (Bradley, 1930), all from Viola Springs Formation, roadcut along west side of U.S, Highway 99, 5 km south of Fittstown, Pontotoc County, Oklahoma (except 9, 10, Lawrence Quarry, approximately 10km southwest of Ada, Pontotoc County). (1–3) Cephalon (OU 12121), anterior, dorsal and lateral views, ×5.25, collection 99-51; (4–6) cephalon (OU 12123), anterior, lateral and dorsal views, ×6, collection 99-float; (7, 8) cephalon (OU 222765), lateral and dorsal views, ×5.5, collection HW99-51; (9, 10) cranidium (OU 12124), latex cast from external mold, dorsal and anterior views, ×5.25.