84 Mr. D. M. S. Watson on Pleurosaurus mid 



E. Anal area. 

 H. Hinge. 

 I, II, & III. First and second and third veins of squama. 



U. Ulnar vein. 

 1-12. Eadial nerviires. 

 V.S. Vena spuria. 

 T. Triano'ular area. 

 Fiff. 3. Labidnra henyalensis. Dolirn. X o. 



Plate IV. 



Fig. 4. Marava wnUacei, Dolirn {=gr(mdis, Dubr.). X 8. 

 Fig. 5. Labia aunulata, Beauv. X 10. 

 Fig. 6. Otcetospania australica, Dubr. X 8. 



Plate Y. 



Fig. 7. Forficuhi auricularin. L. X 8. 

 Fig. 8. Epai-chus insignis, Haan. X 6. 

 Fig. 9. Doru lineare, Escb. X 6. 



XT IT. — Pleurosaiinis and Ihe Homologies of the Bones of the 

 Temporal Region of the LizarcVs Skull. By D. M. S. 

 AVatson, jM.Sc.j Lecturer on Vertebrate Palaeontology iu 

 University College, London. 



[Plate YI.] 



In the most primitive known Tetrapod skulls, represented for 

 us by the Amphibian Fteroplax and the Reptile Seymouria, 

 there are three bones in the temporal region. The outer of 

 these is usually much the largest and has the following 

 relationships : — 



It covers a large area on the side of the skull, being 

 connected by suture with the quadrato-jugal below, the jugal 

 and postorbital iu front, and the intertemporal and " supra- 

 temporal ^^ above. Its posterior border is bent inwards 

 below the otic notch, and covers the back of the quadrate ; 

 fiually, this flange unites with the pterygoid in a long suture. 



The other two temporal bones lie entirely on the surface, 

 and come iuto relationship with no cartilage-bone, unless, 

 ))erhaps, the epipterygoid. 



Most palseoutologists — Broili,Boulenger, Gadow, v. Huene, 

 Jaekel, for example, amongst those working to-day — call 

 the outer bone the squamosal, and Broom has recently 

 been converted to this view ; but Case has consistently 

 called it a prosquauiosal, and some other workers object to its 



