Frog's Parietal

An adult human skull is composed of 22 bones which are described by a standardized terminology. This system of anatomical terms has for years been extrapolated to other craniates. In 1835 Dugès made such an extrapolation from the human parietal bone to one of the bones within the roof of the skull of nascent frogs. What led Dugès to infer this homology is unclear, but his supposition has nevertheless been widely adopted since. In the following it will be argued that the bone in frogs which Dugès equated with the human parietal bone does not exist in man: it, however, is present in other mammals in the form of a tentorial ossification. Also, that the counterpart to the human parietal bone actually occurs among frogs.