The supratemporal bridge is formed by the squamosal and postorbital (Fig. 59, C, _Pt.f_), the latter being continued forwards and fused with the postfrontal (A, _Pt.f_). The postorbital joins the ascending branch of the jugal, both together forming the hinder border of the orbit; this is bordered below chiefly by {296}the maxillary, which is long, while the anterior process of the jugal is much reduced. There is no pre-orbital fossa. The nares are terminal and lateral, well separated by the premaxillaries. The posterior temporal bridge is formed by the squamosal and parietal, the bridge extending laterally over the quadrate and enclosing a wide space between itself and the buttress-like expansion of the lateral occipital bone. The space enclosed between this occipital buttress, the quadrate, and the pterygoid support of the latter is likewise very large; it is of course the cavity of the middle ear, and as such is crossed by the columellar chain of the ear. The infratemporal bridge or jugal arch is formed by the jugal, which joins the descending process of the squamosal, and by the quadrato-jugal, which is small and fused with the quadrate. The latter is consequently very firmly fixed. The teeth are acrodont, ankylosed in one series with the supporting bones, triangular and much worn down in older specimens. Originally there seem to be several in the premaxilla, but the adult bite with the somewhat curved-down portions of the premaxillaries themselves, or with what remains of the fused bases of the original teeth, which then, together with the bone, look like one pair of large chisel-shaped incisors. The lateral edges of the palatines likewise carry teeth, those of the mandibles fit into the long slit-like space between the palatine and the maxillary teeth. Young specimens have a few small teeth on the vomers, which are large, and separate the long choanae from each other. The pterygoids form an anterior symphysis, posteriorly they rest upon short processes of the basisphenoid and send short flanges to the quadrates.