THE SKULL IN TILE CHAMELEONS. 81 



with a rounded lower end and a sharp thin upper part — the nasal process (n.px). Only 

 the broad end is seen in the lower view ; for the maxillaries (mx) close under it, as they 

 close under the paired rudiments in the human embryo ! This wedge is tliickened again, 

 above (fig. 3), where it binds together the two prefrontals ; it then runs sharp and thin 

 between the nasals. The maxillaries (mx) are large bones, high in front, and gently 

 lessened backwards into a sharp jugal process. In front they have a deep round notch, 

 in which the outer nostril and its enclosing cartilages {e.7i, al.n) lie. In front each bone 

 is not far from its fellow, and is ornate; behind the nostril the bone rises as a strontr 

 rounded process, which props up the prefrontal. Descending thence in a crescentic 

 manner, it leaves a space for the small oblong lacrymal (fig. 1, I), inside which is seen 

 the large triangular lacrymal canal {I. c), bounded on its inside by the anteorbital 

 plate of the prefrontal. 



Only the maxillary (above) bears teeth ; and these are confluent with the jaw. 

 From the lacrymal the jugal (;) runs back, no larger than it at first; but bending 

 up behind at more than a right angle, it becomes a broad anfl thick bar, finishing the 

 orbit, propping up the fore fork of the squamosal, and is itself clamped in front by the 

 styloid lower crus of the postorbital. 



The lower surface of the skull (fig. 2) sliows the maxillary as having a wide palatine 

 plate up to its junction with the palatine bone {pa) ; thence it becomes less than 

 half its anterior width. Behind the junction of the maxillaries in front, in the semi- 

 oval space formed by their divergence, we see the single vomer [v) ; its length is one 

 half greater than its breadth ; its sides are concave ; and so is its inferior surface : it 

 projects into the notch between the maxillaries ; and the palatines articulate with 

 its posterior margin, which is a rounded notch. It is a thick but not very high bone 

 (Plate XVIII. figs. 2-5). 



The ascending processes of the palatine bones (fig. 2, pa) are united together by 

 suture for a greater length than that of the vomer; together these upper arched 

 spurs are not equal to the lower flat region of these bones. 



The lower part of each palatine grows outwards and forwards, and articulates 

 obliquely with the palatine plate of the maxillary ; behind, the inner margin of each 

 bone, at the lower plane, approaches the mid line ; and thus a grooved space is formed, 

 into which both the internal nostrils (choanae, i. n) open. These passages are large, 

 oval, with their long axis parallel to the axis of the skull, and their inner boundary 

 the notched tract between the lower and upper part of the palatines. In front of and 

 outside each inner nostril there is a membranous space, bounded on its inside by the 

 vomer, and on its outside by the palatine process of the maxillary. Above this space, 

 and above the vomer, there is in most Lizards, as in the Serpents, a thin curled laminar 

 bone — the " septo-maxillary ; " it does not exist in the Chameleon. 



Where the broad lower part of each palatine articulates with the pterygoid {pij). 



