30 



MAEINE EEPTILES OF THE OXEORD CLAY. 



nares, while its thinner outer edge uuited with the premaxillse. Posteriorly tlie bone 

 is broader, and on both its outer and inner borders has shelf-like facets for union with 

 the neighbouring bones, the outer probably joining the maxilla and premaxilla {mx.f.), 

 the inner meeting the vomer in front and the pterygoid behind. The notch marked nf 

 in the figure is apparently the posterior angle of the internal nares. It is only fair to 

 state that in one specimen, including many parts of the skull, there is a bone probably 

 belonging to the palate, which is of considerably different form, and may be a palatine. 

 In fact, till a skull is found with the palate preserved in something like its original 

 condition, it will remain impossible to be certain of the form and relations of its 

 constituent elements. This remark applies especially to the vomers. The bones that 



Text-fis. 19. 



A. 



? Left vomer of Ophthalmosaurus : A, outer side ; B, palatal surface ; C, inner side. (R. 3533, f nat. size.) 



h.n., border of nasal opening ; n., narial groove ; pal., surface of union with the palatine ; 



pmx.f., surface for union witli the premaxilla; v.f., surfaces of union with the opposite vomer. 



are here regarded as vomers are figured in text-fig. 19 ; they belong to a small skull, 

 of which most of the bones are preserved in a separate condition. The form in side 

 view is shown in text-fig. 19, A and C, while the narrow palatal surface is seen in 

 19 B. The outer face bears on its anterior pointed region a facet probably for 

 union with the premaxillae, while on its posterior and lower border is a surface which 

 may have united with the palatine {pal.). The rounded notch marks the inner 

 border of the internal nares. The outer face in front of the narial notch (n.) bears 

 along Its upper and lower edges facets for union with the vomer of the opposite 

 side (v.f.). On the whole, these bones agree very well with what can be seen of the 



