Edaphosaurus occipital complex; Basisphenoid (genus indet.); Eryops basicranial bones, Samuel Wendell Williston, 1925

Illustration of hindmost portions of the skulls of edaphosaurus, eryops, as well as an unidentified basisphenoid from the osteology of the reptiles (1925). Date: 1925. The Osteology of the Reptiles p24