Tympanic bullae are large, robust, and firmly attached to the underside of the endocranium.    From Wordnik.com.  [PLoS ONE Alerts: New Articles] Reference

The elongated overall shape of the braincase has not changed much in the course of more than two million years of human evolution, despite a big increase in endocranium volume.    From Wordnik.com.  [Telegraph.co.uk - Telegraph online, Daily Telegraph and Sunday Telegraph] Reference