600 ON A SOUTH AFRICAN DIAPTOSAURIAN REPTILE. [May 29, 



cates that the skull has the temporal region roofed or fenestrated ; 

 the second letter, P or A , indicates that a precoracoid is present or 

 absent ; and the third, PI or T, that the pelvis is plate-like or 

 triradiating. It will be observed that all the orders occurring in 

 the Permian have the pelvis plate-like, all have notochoi-dal 

 vertebi-a3, and most have retained the precoracoid, while all those 

 that fiist appear in the Tiias show no trace of a precoracoid. I 

 have included among the Diaptosaurians a new suborder, or 

 possibly order, Proterosuchia, of which ProUrosimlius may be 

 taken as the type. Boulenger is inclined to place it near to 

 Ornithos'uchus, but the palate is very different in the two genera, 

 and the presence of rows of teeth on the pterygoids of the African 

 genus seems of sufficient importance to remove it from the 

 Phytosauria. It seems to me woi'thy of being placed in at least 

 a distinct suborder. The Phytosauria might, I think, be included 

 among the Diaptosaurians. Further research in the Permian 

 and Triassic rocks is pretty certain to reveal a large number of 

 new groups — groups which are ancestral to the Plesiosaurs, the 

 Chelonians, the Lizards, and the Ichthyosaurs at least. 



EXPLANATION OF THE PLATES. 



Ang., Angulare; c, centrale ; CI., clavicle ; Co., coracoid ; D., dentary ; JP., fibula 

 f., fibulare; J^r., frontal ; IIy.,\\yo\A; i., intermedium ; J.cZ.,interclavicle; J^., ilium 

 Is., ischium; Ju., jugal ; £., lachrymal; Mx., maxilla; Na., nasal; Orb., orbit 

 Fa., parietal ; Pal., palatine ; Pmx., premaxilla ; Po.f., postfrontal ; Po.o., postorbital 

 Pi., pterygoid; P.Vo., prevomer ; Pu., pubis; S.Ang., surangv^lar; So., scapula 

 Sg., squamosal; /S.Sc, suprascapular; I"., tibia ; iJ., tibiale ; T.P., transpalatine ; 1,2, 

 3, 4, tarsalia ; I, II, III, IV, V, metatarsalia. 



Plate XL. 

 Fig. 1. Restoration of skull of Soioesia ij'owni. Nat. size. 



2. Jiestorsdion of Tpalate of Mowesia hrowni. Nat. size. 



3. Specimen A showing portion of mandible and cast of jugal and other bones. 



Nat. size. 



4. Jugal and postorbital bones of Sowesia hrowni (specimen B). Nat. size. 



5. Portion of upper surface of skull of Soioesia browni (specimen B). Nat. size. 



6. Kemains of palate as shown in specimen A. Nat. size. 



7. Portion of left dentary showing teeth (specimen A). X 3. 



8. Middle portion of left maxilla showing teeth (specimen A). X 3. 



9. Posterior part of left maxilla showing teeth (specimen R). X 3. 



10. Shoulder-girdle as preserved (specimen B). Nat. size. 



11. Restoration of shoulder-girdle of Soioesia hroivni. Nat. size. 



12. Shoulder-girdle of yoiing Splienodon, after Howes & Swinnerton. 



13. Humerus of Sowesia broioni. Nat. size. 



Plate XLI. 

 Fig. 14. Anterior caudal vertebra of Soioesia broioni. Nat. size. 



15. Side view of pelvis of Sowesia broioni. Nat. size. 



16. Side view of pelvis of Erythrosuclms africanus. X xg. 



17. Inner view of right ilium of Sowesia broioni. Nat. size. 



18. Under view of left pubis of „ „ „ 



19. Front view of left femur of „ „ ,, 



20. Proximal end of left femur of „ „ „ 



21. Front view of left tibia of „ „ „ 



22. Side view of left tibia and fibula of Sowesia broioni. Nat. size. 



23. View of the foot as isreserved. Nat. size. 



24. A second view of the foot as preserved. Nat. size, 



25. Restoration of the tarsus and metatarsus of Soioesia. Nat. size. 



26. Foot of Sjjhetiodon punctatus. Stage R. Magnified. 



27. „ „ „ Stage Q. Magnified, after Howes & 



Swinnerton. 



28. Foot of Procoloplion trigoniceps. Nat. size. 



