Here the opisthotic bone appears in the occipital region, as in the adult Chelonian.
2
Parietal bones separated by the supraoccipital; prootic and exoccipital separated by the enlarged opisthotic. Pectoral arch suspended from the skull; no mesocoracoid arch.
3
The opisthotic lies between the epiotic and the lateral occipital with which it ultimately fuses; in some birds, e.g.