186 REPORT OF NATIONAL MUSEUM, 1898. 



is ou a much higher phiue than the paUitiues iii Chamii'leouidai and 

 Geckonidai, the palatines curving downward to meet the pterygoids. 

 The latter are generally horizontal, but in Chamceleon they are in a sub- 

 vertical plane, their free rounded extremities descending and fitting on 

 the inner side of the mandible. They do not quite reach the quadrate. 

 lu the Agamidai, lguanidiT3, and Geckonidte the internal extremity of 

 the ectopterygoid is directed inferiorly, forming a downwardly directed 

 angle ou each side of the palate. In the Amphisbseuia the structure of 

 the palate is much more compact than in other lizards. The i^alatines 

 are in contact on the middle line and there is no palatomaxillary fora- 

 men. That is, the palatine is in close contact with the maxillary, the 

 ectopterygoid being, tightly wedged in between them. The pterygoids 

 are in contact throughout their length with the sphenoid, and the prox- 

 imal end of each is tightly wedged between the latter ami the quadrate. 

 The character of the petrosal must be attended to by anyone who 

 desires to understand the relations of the Sauria among themselves. 

 In no member of the Sauria is the trigeminus foramen closed ante- 

 riorly by bony tissue, but it is inclosed by the membrane which forms 

 the anterior wall of the brain case. The petrosal is divided into two 

 parts by the deep notch whose fundus forms the j)Osterior border of this 

 foramen, which may be called the supra and infra foraminal portions. 

 The infraforaminal portion is divided in most of the families by a longi- 

 tudinal, keel-like ridge, which forms the superior border of a groove 

 whose inferior wall is formed by the sphenoid. This groove is not pres- 

 ent in Heloderma and is very shallow in Xenosaurus. It is wanting in 

 the Anuiellidie and Amphisbicnia. In the Geckonida; it does not exist, 

 nor is the petrosal notched by the foramen, while the anterior border of 

 the petrosal forms a free crest which extends from above downward and 

 backward. In the Chamicleouidie, Agamidie, Iguanidae, and Anolidse 

 (families with papillose tongues) the supraforaminal part of the petro- 

 sal is short and is bounded by a convex anterior border which marks 

 the position of the anterior semicircular canal. In the Nyctisaura, 

 Thecaglossa, Dii^logiossa, Leptoglossa, and Amijhisbienia (families 

 with smooth or squamous tongues, except Anniella, Dij)loglossa, and 

 Nyctisaura) the i^etrosal is produced beyond this curved border below 

 the parietal. In many forms an outline of the semicircular canal 

 which forms the boundary in the other saperfamilies may be traced, 

 whence I have termed this part of the petrosal posterior to it "the 

 arched body" in my former system of the Sauria.^ The petrosal is 

 produced farthest beyond this arcade in the snakelike forms of the 

 Anniella and Amphisbienia, reaching almost to the orbit in Lepido- 

 sternum. The relation to the parietal differs, the diflerences resulting 

 from the greater or less redu(;tion of the primitive supratemporal roof 

 and the greater or less entrance of the parietal into the lateral wall of 

 the brain case. In most of the families it is little or not decurved to 



' Proceedings, Academy of Natural Sciences, Philadelphia, 1864, p. 224. 



