The morphology of E. microcephala is most similar to E. trinacria and E. rushforthii. The central undulation on the dorsal margin of E. microcephala is more prominent than the faint hint of a swelling on the dorsal margin of E. microcephala. The two ventral undulations are more prominent on valves of E. microcephala than those on valves of E. trincacria and are not visible on E. rushforthii.