endocranial cast, a cast taken from the inside of the cranium (braincase), frequently used by paleoanthropologists to determine the shape and approximate size of the brains of fossil animals including extinct hominids and other primates. Since only skeletal materials are preserved in the fossil record, endocranial casts and measures of cranial capacity are the only available means of estimating brain size and configuration in fossil hominids. Cranial capacity, however, gives only a rough idea of brain size (in modern humans, the brain takes up only about two-thirds of the total cranial volume), and brain size cannot, in any case, be directly correlated with intelligence.