Skull
Aiton's Encyclopedia (1910)
in animal physiology, the bony or cartilaginous framework of the head. It contains the brain and supports the face parts. All vertebrates, save the lancelets, have skulls. No animal without a backbone has a skull. The word skull means bowl, or cup. The skull is divided into the skull proper, known as the cranium or brain-box, and the facial region or face. For the eight bones of the cranium and the fourteen of the face the reader is referred to the article on Skeleton. In all mammals, that is to say, animals which suckle their young, the skull is composed of bones corresponding to those of the human skull, but the skull takes many shapes. In mammals other than man the cranium is small in comparison to the facial bones. Birds have a large cranium and small facial bones except that the beak is elongated. There are more bones in the skull of a bird than in that of the mammals. The cranium of the reptile is small and the facial bones large. The skull of the fish shows great diversity. The bones are so changed in shape and number that it is difficult to compare them with the bones of the mammal skull. Formerly the ethnologist or student of the human family based his classification of races on language and complexion, but of late scientists have come to the conclusion that the only safe basis of classification is the shape of the skull. The study and measurement of the skull form a distinct branch of science known as craniometry.
What Has Changed in the Last Century
The anatomy in Aiton's 1910 account still holds: eight cranial bones, fourteen facial, and no invertebrate with a skull. What has collapsed entirely is its closing claim that "the only safe basis of classification" of human races is the shape of the skull. Craniometry, treated here as a rising science, was discredited over the following decades — skull shape proved plastic (Franz Boas showed it shifting within a single immigrant generation), the racial typologies it supported were used to justify eugenics and worse, and human variation is now traced through DNA, which shows far more difference within any so-called race than between them. The skull remains central to one field Aiton could not have anticipated: the fossil crania found since 1924, beginning with the Taung child, that map human evolution.
Written for this edition, 2026.