RY C. W. DE VIS, M.A. 1133 



ordinary form it goes but 3 to 3J in the same length. In form it 

 differs no less ; attenuation at either end together with increased 

 convexity on its outer side renders it comparatively crescentic in 

 shape. The alveolar tract of the premolar and canine is on the 

 other hand sensibly concave externally — that of the whole dental 

 series is therefore slightly undulatory, while in taguanoicUs it is 

 uninterruptedly convex outwards. The molars, compared with 

 those of typical skulls, have a peculiar facies arising from the 

 obliquity of the cross valleys and much greater smoothness of the 

 grinding surfaces. In the three foremost of the permanent molars 

 there is but a remnant of the sharp enamel fold at the base of 

 each of the outer cusps seen in taguanoides, these cusps themselves 

 have much less asperity, and the inner cusps are reduced to a mere 

 prominence of the border of the anterior angle of the tooth, the 

 hinder of them having become obsolete. In contour the chief 

 difference is presented by the last molar which is relatively 

 narrower and more regularly trilateral. 



In the lower jaw the premolar is considerably smaller than in 

 any available mandible of P. taguanoides. Also its subsidiary 

 lobes both fore and aft are disproportionately smaller than the 

 principal one. The first permanent molar is tricuspidate ; the 

 anterior moiety of the tooth, cleaved in taguanoides by an oblique 

 sulcus, being here undivided — posterior to it the grinding surface 

 of this and of the rest of the molars is formed by a series of broad 

 shallow subcircular basins, bounded externally by much less 

 prominent cuspidate angles than those of taguanoides, tilted more 

 strongly outwards and crossing the alveolar axis more obliquely. 

 There is further a notable difference in the shape of these lower 

 grinders arising from the absence of the strong anterior and mesial 

 contractions which in taguanoides give them somewhat the look of 

 a series of aludels in place — in the mandible under notice the 

 valleys are nearly of the full width of the crowns. The diastema 

 is longer and slopes more gradually forward to the outlet of the 

 incisive socket than in taguanoides. It has no trace of teeth 

 overtly, but in this respect the animal probably varies as much as 

 taguanoides itself, which has in Queensland examples from one to 



