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a median crest posteriorly. Two antero-superior projections of the supra- 

 occipital embrace the parietal on each side below the crest; while it is over- 

 lapped, just below, by the anterior extremity of the prootic. This does not 

 extend so far forward as the supraoccipital. In front of, and below, this 

 point, the parietal is decurved, and forms a considerable part of the lateral 

 wall of the cranium, though with but moderate antero-posterior extent. 

 The lateral wall extends to the body of the sphenoid, where extensive sutural 

 surface has received it. I can find no suture crossing it; and it is apparently 

 all alisphenoid or all parietal. A part of the parietal is, however, undoubt- 

 edly decurved in front of the alisphenoid. The structure is quite as croco- 

 dilian as ophidian in this point. 



The postero-lateral angles of ihe parietal send the parieto-quadrate 

 arches to the opisthotic, which sends an ascending process to meet the 

 parietal, as in lizards. It differs from most of these in the presence of an 

 intermediate bone, which has been observed by Marsh, and which would 

 appear to be a dismemberment of one of those with which it is in contact. 



The anterior ala of the prootic overlaps the alisphenoid largely. Its 

 posterior lamina may, or may not, meet the expansion of the exoccipital on 

 the upper face of the suspensorium. Interiorly, it is in contact with the 

 outer and posterior base of the sphenoid. 



The supraoccipital is roof-shaped. The posterior extremity of the parietal 

 rests upon it, sending lateral arches to the opisthotic, as in most Lacertilia. 



The exoccipital is distinct, and bears a very small segment of the 

 occipital condyle. 



The opisthotic stands obliquely upward and forward, and furnishes a 

 glenoid cavity for the articulation of the quadratum. It has a process, directed 

 upward and forward, which occupies a concavity on the inner face of the 

 squamosal, which has the same direction. 



The squamosal is a subrhombic bone in a vertical plane, and is fiat 

 below, and proximally presents a longitudinal external angle ; distally, it is 

 slender and prolonged, and receives the posterior process of the post-frontal. 



The basioccipital presents a strong transverse condyle. It is a massive 

 bone, and presents infero-laterally two powerful processes, which diverge pos- 

 teriorly, and present broad, rugose, ovate faces of insertion. There is an 

 obtuse keel on the middle line below, which bifurcates posteriorly to eacli 



