Here the opisthotic bone appears in the occipital region, as in the adult Chelonian.
The opisthotic lies between the epiotic and the lateral occipital with which it ultimately fuses; in some birds, e.g.
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 apex of the cochlea is turned towards, and almost reaches the anterior wall of the occipital condyle; at most it makes but half a twist or turn; it possesses both Reissner's membrane and the organ of Corti.
The head is large, and the skull elongated, and elevated posteriorly into a transverse occipital crest.
