On the other hand, some reptiles have the occipital condyle divided into two and produced either by the basi-occipital or by the exoccipitals.
Here the opisthotic bone appears in the occipital region, as in the adult Chelonian.
The head is large, and the skull elongated, and elevated posteriorly into a transverse occipital crest.
The opisthotic lies between the epiotic and the lateral occipital with which it ultimately fuses; in some birds, e.g.
As regards their distinctive features, the antlers are of a complex type and situated close to the occipital ridge of the skull, and thus far away from the sockets of the eyes, with the brow-tines in adult males palmated, laterally compressed, deflected towards the middle of the face, and often unsymmetrically developed.
The proOtic encloses between it and the lateral occipital the fenestra ovalis, into which fits the columella of the ear.
Oc, Occipital con dyle.
Birds possess an ear-muscle which at least acts as a tensor tympani; it arises near the occipital condyle, passes through a hole into the tympanic cavity, and its tendon is, in various ways, attached to the inside of the membrane and the neighbouring extracolumellar processes.
The squamosals form part of the cranial wall, being firmly wedged in between the quadrate, prootic and occipital bones.
Fully developed pre oc, Occipital condyle.