In Birds, the epiotic and opisthotic are early united with the supra- and exoccipital; and at a later period the prootic is also indistinguishably fused with the adjacent parts.
In Reptiles, the prootic and opisthotic frequently remain distinct even in the adult.
Laterally each is united with the pterygoid andopisthotic of its side.
Further forwards the long slit-like opening between the exoccipital and opisthotic is the =internal auditory meatus= (fig.
They are connected by the supratemporal with the epi-otic andopisthotic regions of the cranium.
Thus the epi-otic often unites with the supra-occipital, and the opisthotic with the exoccipital.
The pro-otic ossifies, and unites with the epi-otic and opisthotic before they coalesce with any other bones.
In Chelonia the opisthotic remains separate, in all other living reptiles it fuses with the exoccipital.
Between the pro-otic and opisthotic as seen in a longitudinal section of the skull is a large opening constricted in the middle.
The auditory or periotic capsule of the turtle is rather large and its walls are well ossified, epi-otic, pro-otic and opisthotic bones being present.
It commences to ossify from three centres corresponding to the pro-otic, epi-otic and opisthotic of lower skulls, such as those of the Turtle and Crocodile.
The pro-otic lies in front of the exoccipital and together with the opisthotic forms the hind border of the fenestra ovalis.
In the last chapter I finished the evidence given by the consideration of the mesosomatic or opisthotic nerves, and the segments they supplied.
I have dealt with the opisthotic segments of the vertebrate, including therein the segments supplied by the facial nerve, and shown that they correspond to the mesosomatic segments of the palaeostracan; consequently the facial (VII.
As already mentioned, the facial nerve is usually included in the trigeminal or pro-otic group of nerves, the opisthotic group being confined to the glossopharyngeal and vagus.
But this, as mentioned above, does not hold for the Proteidae, which possess an opisthotic of relatively large size, distinctly separate from the exoccipital and prootic.
Since the remainder of the posterior wall of the otic capsule consists of cartilage, meeting the exoccipital, it may be that the opisthotic becomes the operculum in frogs.
The opisthotic is missing in all except Proteidae (but see discussion of the ear).
On the other hand, Necturus and Proteus alone among living salamanders have a distinct opisthotic on the posterior wall of the otic capsule (Fig.
Opisthotic Wing This term refers to the laterally directed, posterior part of the opisthotic that is visible in occipital, lateral and ventral views.
The distal part or tip of the opisthotic wing is not visible in dorsal view on skulls of ferox or spinifer.
In ventral view the opisthotic wing is most easily seen and is wider in muticus than in spinifer or ferox.
Frequency and Degree of Development of Opisthotic Exoccipital Spur of North American Species of the Genus Trionyx (excluding ater).
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.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "opisthotic" in a variety of sentences. We hope that you will now be able to make sentences using this word.
