92 



Mr. D. M. S. Watson on Pleurosauius and 



enters into the nostril and posterior edge forms a good deal of 

 the margin of the orbit. Its upper edge is suturally connected 

 with the nasal and frontal, and its lower edge is overlapped 

 b}'^ the maxilla and has a suture with the lachrymal. A 

 well-marked foramen enters the bone just above the edge 

 of the maxilla. 



The lachrymal (Lac.) is a very small bone forming a part 

 of the orbital boundary, and wedged in between the prefrontal 

 and maxilla. 



The frontal is a comparatively small bone which forms 

 part of the orbital border and articulates with the prefrontal, 

 nasal, parietal, and postorbital, as well as with its fellow. 



The parietal has a long suture with its fellow, interrupted 

 at one point by the small oval pineal foramen ; anteriorly 

 it is in contact with the frontal and postorbital, posteriorly 

 with the squamosal, but I cannot be certain of its exact 

 relationship with the latter bone. 



Fis-. 4. 



PMx. 



QuJ. 



Lac. 



Restored lateral aspect of the skull of Pleurosaurus goldfussi, X 1. 

 Keference-letters as in fi"-. 3. 



The postorbital (P.O.) is a large bone which forms a large 

 part of the borders of the orbit and temporal fossa. Its inner 

 end is in contact with the frontal and parietal, and below it 

 has a very long suture with the jugal, extending backwards 

 along its upper edge to overlap the anterior part of the 

 squamosal and the quadrato-jugal. 



The jugal (Ju.) is>a bone which forms a small part of the 

 lower border of the orbit, and extends backwards below the 

 postorbital to articulate with the quadrato-jugal. 



The squamosal (Sq ) is an L-shaped bone which forms much 

 of the border of the temporal fossa. Its inner leg is in contact 

 with the parietal, but the details of the attachment are not 



