The bones of the face in osseous Fishes are exceedingly numerous and irregular, neither is, it easy to identify many of them as being at all analogous to those which normally make up the face. even of those Reptiles which present moveable cartilages of the nose of other Ver tebrata ossified and entering into the composi tion of the facial skeletOn.
Besides the suborbital chain of bones (g,g,g,g) above inentioned as partially surrounding the orbit, and which in the Gurnards and other hard-cheeked Fishes cover the cheeks as with a bony case, entitling them to the name applied to them by Cuvier of " joues cuirasses," another chain of bones called the supra-temporal is not unfrequently met with, placed on each side, over the interval that separates the external from the middle prominent ridge, developed from the exterior of the cranium so as, together with these projections, to cover the articulation of the supra-scapular bone (46). These bones are evidently peculiar to Fishes, and, like the sub orbital, must be referred to the exoskeleton and not deemed to belong properly to the o,seous system. In this light they will be con sidered in another place.
the most complicated condition of this portion of the skeleton. The higher cartilaginous Fishes, however, ( Chondropterygii,) forin a very petnarkable exception ; for -in the Rays and Siuirks the face is reduced to a very simple condition, in consequence of the want of sepa ration between the different pieces of the skele ton, consequent on the permanently cartilaginous state of the osseous system in these tribes.
The suborbital bones in Fishes (fig. 437, g, g, g) form a kind of chain composed of a very variable number of pieces which surround the inferior and external margin of the orbit, covering the muscles of the face instead of giving attachment to them, a circumstance which induced Cuvier to believe that they did not normally belong to the series of facial bones. They are doubtless referable to the exo-skeleton or cuticular bones so largely developed in sorne fishes, and in this light they will be considered in another place.
The prcenasal bones, Owen ; bones, Cuv.) of a Fish (fig. 436, 20) are found in a situatiorr very analogous to that which they occupy in the higher Vertebrata. They form the internal boundaries of the nasal cham ber, and articulate superiorly with the frontal (1). These bones are regarded by Professor Owen as being the representatives of the The palatine arch or osseous roof of the mouth is composed of analogous bones in all the different races of Vertebrata; but in the lower Vertebrata there are found in connection with this region of the skeleton several pieces that have no representatives in the higher classes.
'The palatine bones (22) are easily recog nisable in Fishes, occupying the same place as in Serpents (fig. 439), and, moreover, further distinguished by being frequently armed with teeth which project into the roof of the mouth. In Reptiles, also, teeth are often attached to them where they assist in forming the cavity of the mouth. These bones are found in all the vertebrate classes.
The transverse bones (24) occupy nearly the same situation in Fishes as in Reptiles, but in the latter they are most distinctly seen. In the Crocodile each is a bone of considerable size, composed of three branches and extending between the pterygoid bone and the junction of the jugal, the maxillary, and the posterior frontal. This bone is not met with, either in Birds or AIammalia, not even in the fcetal period of their existence.
The internal pterygoid bones(25) are like wise distinct in fishes, stretching between the palatine bone and that tshich supports the lower jaw (26). In Reptiles they are large and important detached bones, occupying the po sition of the pterygoid processes of the sphe noid ; but in Birds and Mammals they become completely anchylosed with the sphenoid, so that, by the human osteologist, they are erro neously regarded as apophyses of that bone.
The zygomatie, Owen, (jogai, Cuvier,) are in Fishes broad pieces, generally of a triangular shape, placed behind the transverse, which by their inferior angle support the articulation of the lower jaw. In Reptiles, too, it may al ways be distinguished by the latter circum stance, and in Serpents It is particularly re markable (figs. 438, 439, 26), standing out from the squamo-temporal (mastoid, Cuv,) like a branch, and thus giving that extrdor dinary tnobility to the articulation of the in ferior maxilla which enables those Reptiles to swallow prey so disproportioned to the size of their mouths. In other Reptiles this mobility is in a great degree lost. But in Birds the zygomatic bones again assume very important functions. They are here known by the name ossa quadrata, and standing out to a con siderable distance from the skull allow of great mobility to the zygomato-maxillary articulation, and also to the bones supporting the superior maxilla. In Mammalia this zygomatic bone is so firmly and undistinguishably united to the temporal that the human osteologist merely calls it the zygomatic process of that bone.
The masto-temporat, Owen, (temporal, Cuv 23), are in Fishes and Reptiles distinct elements of the skull, which in the human cmnium are consolidated with the other elements com posing the "os temporis." The styloid bones (29), mererudiments r., .