OPHTHALMOS AUEU S. 



29 



The palatines are not well known. The bone figured in text-fig. 18 is believed to 

 be one of these elements, since in its general characters it is similar, so far as can be 

 seen, to the palatine of Ichthyosaurus zetlandicus. The figure is drawn mainly from 



Test-fig. 17. 



fitsym 



Left pterygoid of Opluhalmosaurus : A, upper surface ; B, lower (palatal) surface. (E. 2180, 3 nafc. size.) 



hs.pt.f., facet for union with the pterygoid process of the basisphenoid ; d.p., dorsal process ; e.p., outer 

 process ; g.st., groove for the reception of the stapes ; i.&., internal border ; in.p., inner process ; 

 1 pas.f., facet for union with the paraspheuoid (?) ; pt.sym., symphysial surface for opposite pterygoid ; 

 q.f., surface for union with the quadrate ; »•., dorsal ridge ; v.f., facet for vomer ('?). 



Text-fiff. IS. 



? Eight palatine of OpJithalmosaurus, from below. (| nat. size.) 

 ap., anterior process ; mx.f., facet for masiUa ; pt.f., facet for pterygoid ; ?i?, border of internal nares, 



the right bone, but the posterior portion has been restored from that of the left side. 

 If this interpretation be correct, the bone would seem to consist of a long anterior 

 process {a.p.), the inner rounded border of which formed the outer side of the internal 



