CLASSIFICATION OF VERTEBRATA 26 



from Lacertidae by the simple non-retractile tongue. Limbs 

 variable. South and tropical Africa and Madagascar. 



Zonurus, with osteoderms covering the body. 



Chamaesaura, serpentiform, limbs vestigial. 



5. Anguidae. Pleurodont, teeth curved and solid. Body 

 with osteoderms ; head with all three arches. Anterior part 

 of tongue retractile. Eyelids movable. Limbs variable. 

 "With an azygos " occipital " shield. North and South America ; 

 European and Mediterranean ; transgangetic India. 



Gerrhonotus, with limbs. 



Ophisaurus (Pseudopus) and Anguis, without limbs. 



6. Helodermatidae. The pleurodont teeth are grooved in 

 front and behind. Numerous lower labial, poisonous glands. 

 Postorbital arch strong, the others absent. Anterior portion 

 of tongue bifid, protractile. Osteoderms slightly developed. 



Heloderma. Mexico. 



7. Varanidae. Pleurodont. Postorbital arch incomplete. 

 Tongue deeply bifid and protractile. Limbs well developed. 

 No osteoderms. 



Varanus in Africa, Asia, Australia. 



8. Xanthusiidae. Pleurodont. All three arches present. 

 No osteoderms. Eyelids not movable. 



Xanthusia, etc. Central America and Cuba. 



9. Tejidae. No supratemporal arch ; no osteoderms. 

 Tongue long and bifid. Teeth pleuro- to acrodont. Limbs 

 variable. America. 



Teius, Ameiva, etc, 



1 0. Lacertidae. Pleurodont. All three arches present. No 

 osteoderms on the body. Proper eyelids. Tongue bifid 

 retractile. 



Lacerta, etc. Palaearctic and Palaeotropical, excluding 

 Madagascar. 



11. Gerrhosauridae. Pleurodont. All three arches 

 present. Osteoderms strongly developed. Tongue bifid. 

 Limbs variable. Mostly with a lateral fold. 



Africa south of the Sahara, and Madagascar. 

 Gerrhosaurus, Zonosaurus, etc. 



12. Scincidae. Pleurodont. All three arches present. 

 Osteoderms strongly developed. Premaxilla double. Tongue 



