Millikin and Lawley real human temporal bone
This is an unusual item. It looks like it was probably part of a medical skull that was prepared by Millikin and Lawley. Some of these examples had temporal bones that could be removed to examine the ear canal. This would also explain the straight cut to the top of the bone and the hole that would probably have held a pin or hook. There is a nice clear label on the bone.
Unfortunately, this is the only part of the skull and this arrived as an extra bone with a skeleton.