26 BULLETIN 32, UNITED STATES NATIONAL MUSEUM. 



I V. — DiPLOGI.OSSA. 



Cranial arches present; mesostcrnum cruciform; teetli pleurodont; temporal fossa 



roofed ; tongue not sbeathed at tip 5. Zonuridw. 



Cranial arches absent; pre and postfrontal bones uniting above orbit ; surangular, 



articular, and angular bones not distinct ; tip of tongue not retractile. 



6. Pygopodidw. 

 Cranial arches present; mesosternum cruciform; teeth pleurodont; temporal fossa 



roofed ; osteodermal plates ; tip of tongue sheathed 7. Anguidw. 



Cranial arches present ; mesosternum cruciform ; teeth pleurodont; temporal fossa not 



roofed ; no osteodermal plates ; tip of tongue sheathed 8. Xenosauridm. 



Postfrontosquamosal arch wanting; mesosternum without transverse elements ; teeth 



half pleurodont 9. Selodtrmidw. 



V. — Thecaglossa. 



Postorbital arch incomplete ; Meckel's groove open ; nasal bones united ; temporal 

 fossa not roofed 10, Varanidce. 



VI. — Geccovarani. 



Postorbital and postfrontosquamosal arches wanting ; interclavicle minute ; nasal 

 bones united ; tip of tongue not retractile ; occipital condyle divided. 



11. UroplatidcB. 



VII. — Nyctisaura. 



Vertebrae procoelous ; parietal bones united 10. EublepTiaridai. 



Vertebra} amphiccelous ; parietal bones separate 11. Gecconidce. 



VIII. — Leptoglossa. 



a . One premaxillary bone : 

 Parietal bones distinct; temporal fossa roofed; no osteodermal plates. 12. Xantusiidw. 



Parietals united ; temporal fossa not roofed ; no osteodermal plates 13. Teidce. 



Parietals united; temporal fossa roofed ; no osteodermal plates 14. Lacertidce. 



Parietals united ; temporal fossa roofed ; osteodermal plates 15. G errhosauridcc. 



aa. Premaxillary bones two : 

 Parietals united; temporal fossa roofed; osteodermal plates 16. Scincidw. 



IX. — Typhlophthalmi. 



Two premasillaries ; arches present ; occipital segment closely articulated; eye dis- 

 tinct 17. Acontiidce. 



One premaxillary; arches wanting; occipital loosely attached; eye concealed by epi- 

 dermis 18. AnelytropidcB. 



X. — Anguisauri. 



Tongue paiiilloso; one premaxillary; no columella; no arches; occipital closely artic- 

 ulated; eye distinct 10. Aniellida;. 



XL— Opheosauri. 



Teeth half pleurodont ; anterior limbs present 20. Chirotidce. 



Teeth half pleurodont; no fore limbs 21. Ampliisbanidcc. 



Teeth acrodont; no fore limbs 22. Trogonophidw. 



