1054 



BAROX FRANCIS NOPCSA ON RKVERSIBLE 



(text-fig. 9 (14)) and neo-orbital genera as Placochelys (text- 

 fig. 9(15)) can be distinguished. Unfortunately noticing is known 

 about the evohition of this group, tiierefore no conchisions can 

 be drawn. 



Text-figure 9. 



1. Palaeo-oibital skull of primitive Microsauriiin DiplocauliiltB, liatrachiterpeton 



(from Watson). 



2. Neo-orbital skull of specialised Microsauriau Diplocuulidse, Diplocauhis (from 



Douthitt). 



3. PalDco-orbital skull of primitive Stereospondylous Bracliyopidaj, Sati-achosucJius 



(from Watson). 



4. Neo-orbital skull of specialised Stereospondylous Bracliyopidte, Flagiosaurtis 



(from Fraas). 



5. Palaso-orbital skull of primitive Cotylosuurian Diadeotes (from Hueno). 



0. Nco-orbitnl skull of specialised Cotylo.saurian l'rocoloj>hou (from Woodward). 



7. Neo-orbital skull of ])rimitive marine tortoise To.vocheli/s (from liny). 



8. Palajo-orbital skull of specialised marine tortoise Dermoclielys (from Volker). 



9. Neo-orbital skull of primitive higlier'i'beriodont Jlf/cro9omjo7iorfo»(from Watson). 



10. Palnjo-orbital skull of specialised bigher Tberiodont Protacmou (from Watson). 



11. Palajo-orbital skull of Lepidosaurian Ileloderma (from Phisalix). 



12. Neo-orbital skull of Lepidosaurian Platecarpus (from Williston). 



13. Tectorbital skull of Lepidosaurian Varanus (from Scbmidt). 



14. PaluDO-orbital skull of Dranitesaurian '£lacodxis (from IJroili). 



15. Neo-orbital skull of Dranitesauriau Plaoocheli/s (from .Jaokel). 



16. Neo-orbital skull of primitive Archosaurian ISaparkeria (from Broom). 



17. Tectorbital skull of specialised Archosaurian Camptosanriis (from 15. Brown). 



Among the Sauropterygians, the neo-orbital type is met with 

 in Anarosanrus, Pistoscmrios, and Nothosaurus, the palseo-orbital 

 type in Cymatoscmrus and all Plesiosaiuians. In all the Plesio- 



