147 



thi and the nest vertebra. There i a distinct cartilaginous tubercle attached to the lowrr 

 part Of the diapophynt, and assuring this now enlarged proem to support a bony pleurapo- 

 phyiit: thit ia sobeompressed, slightly bent, and tapering to an obtuse apes. The diapo- 

 phyais ia Mill larger in the sixth vertebra, though not morr prominent, the incrraie being 

 chiefly vertical : beneath it there it a larger autogenous hard cartilaginous tubercle a nidi 

 mental parapopnym. The rib is here twice the length of the preceding one, and articulates 

 uitli both diapophyw* and parapophrns. without any intervening vacuity for artery or nervr. 



Presented by Prof. Owen, F.R.S. 



070. The skull of a small Iguana : it shows the characteristic expanded and notched 

 crowns of the maxillary teeth and the single row of simple conical denticles 

 on each pterygoid l>one. //UH tenon. 



671. The frontal, nasal, prcinaxillary, maxillary, lachrymal, malar, postfrontal and 

 m.imlilmlar bones of a large Igiianoid Lizard. 



The posterior margin of the frontal U notched by the fronto-parictal fontanelle : both lnrlir\ 

 mal and poatfrontal are subdivided into two pieces ; the lachrymal foramen is between the two 

 pieces, being here formed like a ' conjugational foramen.' The upper portion of the lachry- 

 mal ia called anterior frontal by Cuvier ; but it can represent only the facial part of that bone, 

 for it tend* down no neurapophysial plate to join the vomer or palatines, forms no part of the 

 lateral walls of the rhinencephalic canty, nor any part of the foramen for the transmission of 

 the olfactory nerves. 



Ilmiterian. 



The lower jaw of an Iguana. 



This shows the pleurodont type of dentition, the teeth being placed in a common alveolar 

 depression without any internal wall. The cavities on the inner side of the base of the anchy - 

 loaiJ teeth are the effects of the pressure from the germs of the t uccessional teeth develo|>ed 

 from the vascular membrane which supplies the place of the internal wall. 



H**teria. 



Genus Draco. 



673. The skeleton of the small flying Lizard (Draco volant). 



There is merely the rudiment of a spine or ridge from the snperoccipital ; an arched trans- 

 verse ridge separates the occipital from the parietal region of the skull. The postfrontal, 

 mastoid and paroccipital project successively from their respective cranial segments, and 

 well manifest their character aa the transverse processes of these. There are 20 vertebra; 

 supporting moveable ribs, which commence apparently at the fifth. Those of the eighth 



, -J 



