"Cranial capacity" refers to the amount of space inside the skull where the brain is located. It is used to measure the size of the brain and is often related to intelligence and thinking abilities. Full definition
The Scottish scientist Robert Broom reported that «we get for the corrected cranial capacity of the Boskop skull the very remarkable figure of 1,980 cc.» (discovermagazine.com)
The changes in average cranial capacity from Morton's seed - based measurements to shot - based measurements can not be reconstructed with any certainty, incorporate erroneous seed measurements made by Morton's assistant, yielded a broad range of changes (− 10 to +12 in3) hidden by Gould's mean, and are confounded by the shifts in sample composition (circa 50 %) between the two rounds of measurement. (journals.plos.org)
Actually, this is just as well considering the games Lubenow plays with cranial capacity (more or less equals brain size). (talkorigins.org)