() MR. F. E. BEDDARD ON THE CRANIAL [Jan. 17, 



by him is Uromastix spinipes, or that in the pai'ticulars to be 

 i-eferred to there is no difference between U. spinipes and other 

 Kpecies of the genus. In U^-omastix, Gegenbaur figures a rather 

 smaller postorbital than in Iguana, and represents the postfrontal 

 of the latter lizard as absent. This interpretation of the bone 

 bounding the orbit posteriorly and intervening between the jugal 

 and the parietal is, I believe, correct; but, as will be seen from the 

 annexed figure (text-fig. 2, p. 5), the postfrontal is not absent. The 

 postfrontal is a very much smaller bone, both actually and rela- 

 tively, than it is in a skull of Iguana tuherculata at my disposal. 

 Fui-thermore, the postorbital in Uromastix spinipes has not the 

 shape that it is represented to have in the drawing of Gegenbaur. 

 It extends backwards along the jugal for a much greater distance, 

 but does not, as is the case with the postorbital of Iguana, reach 

 the squamosal. 



The squamosal in ITromastix spinipes requires some considei-atioii 

 since it appeai-s to differ greatly from that of the Uromastix figured 

 by Gegenbaur, and, indeed, from the squamosal of other Agamid 

 lizards. There is, however, a likeness to the conditions obtaining in 

 Iguaiia, a fact which encourages me in adopting a different view. 

 The bones in question are depicted in the accomjDanying drawing 

 (text-fig. 2, p. 5). As in other Agamids, the squamosal is a bifid 



Text-fig-. 3. 



IJack view of the skull figured on p. 3. 

 St?, second supniteniporal ; other lettering as in text-fia-. 2. 



bone, of which one limb is applied to the jugal and the othej' to the 

 parietal. Posteriorly the squamosal is in contact with the quadrate 

 and appears to be in contact also with the lateral process of the 

 occipital. The whole of this bone is not however, as I think, to 

 be regarded as squamosal. It is true that the examination of this 

 region in the skull of some Lizards might lead to that inference. 

 But in Uromastix (at any rate in U. spinipes) (text-fig. 3) the 

 posterior undivided region of the bone in question is seen to be 

 divided off by a suture, which is equally clear on both sides of 

 the skull. The piece thus cut ofi' from the supposed squamosal 

 is in contact with the quadrate below and with a small bonelet 

 laterally, to which reference will be made innnediately, and which 

 interposes between it and the lateral extension of tlie occipital. 



