. The Ceratopsia. Ceratopsia. 30 THE CERATOPSIA. posterior extremity is bifurcated to embrace the compressed median portion of the alisphe- noids, as shown in fig. 27, and the lateral processes of the vomer extend a little back of the posterior border of the palatines, by which they are in turn embraced. The inferior border of the bifurcated posterior extremity of the vomer is thickened above the pterygoids, and each process presents on its inferior surface a groove into which fits the short, wedge-shaped superior border of the apex of the pterygoid, and the suture thus formed between the vome
. The Ceratopsia. Ceratopsia. 30 THE CERATOPSIA. posterior extremity is bifurcated to embrace the compressed median portion of the alisphe- noids, as shown in fig. 27, and the lateral processes of the vomer extend a little back of the posterior border of the palatines, by which they are in turn embraced. The inferior border of the bifurcated posterior extremity of the vomer is thickened above the pterygoids, and each process presents on its inferior surface a groove into which fits the short, wedge-shaped superior border of the apex of the pterygoid, and the suture thus formed between the vomer and the pterygoids is W-shaped, as shown in fig. 25. Above their contact with the pterygoids the vomers are firmly inclosed throughout their breadth by the palatines. " THE PREMAXILLARIES. The premaxillaries are edentulous. They are much compressed and closely applied to each other. The inferior border is heavy and posteriorly it sends upward and backward a strong process, which is wedged in between the maxil- lary and the posterior descend- ing branch of the nasal, send- ing upward a long, slender wedge which is inserted into a deep groove in the latter. The supero-anterior border of the premaxillary describes the arc of a circle. It is thin below, but thickened above where it meets the anterior extremity of the nasals at the base of the nasal horn. At the summit it is embraced externally by a short but stout descending process of the nasal The nasal is supported from beneath by a strong buttress that runs downward and backward. The external border of this bar or buttress is thick and curves forward. It overhangs a broad triangular fossa of which it forms the posterior border. This fossa is confluent below with that of the opposite premaxillary, though they are separated above by a broad, thin median septum. Posteriorly it connects with the narial orifice by a long foramen. Just back of the base of the buttress which gives support to the superior border of the premaxill
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