xii LACERTAE 513 



these otherwise typical Geckos are the fusion of the nasal bones 

 into one, the small size of the interclavicle, and the non-dilated 

 shape of the clavicles. 



Neither the Eublepharinae nor the Uroplatinae are more nearly 

 related to other Autosauri than are the other Geckos. They are 

 modifications within the sub-order of the Geckones. 



Sub-Order 2. Lacertae. Autosauri with procoelous, solid 

 vertebrae, and with the ventral portions of the clavicles not dilated. 



Cope, 1 discarding oiiter appearances as deceptive in the classi- 

 fication of the Lacertae, laid stress upon internal characters, 

 notably the presence or absence of osteoderms, the formation of 

 the skull, and the structure of the tongue. Boulenger 2 has 

 followed and improved upon Cope's arrangement, and rjas 

 elaborated the classification, which, being used by himself in the 

 three volumes of the Catalogue of Lizards in the British Museum, 

 has also been followed in the present work, with slight alterations 

 in the order of treatment of the families. For our present purpose 

 we diagnose the families as follows, giving preference to such 

 characters as are most easily ascertained : 



Synopsis of the Families of Lacertae. 



Fam. 1. Agamidae. Acrodont. Tongue broad and thick. No osteo- 



derms. Old World, p. 515. 



Fain. 2. Iguanidae. Pleurodont. Tongue short and thick. No 



osteoderms. America, Madagascar, Fiji Islands, 

 p. 528. 



Fam. 3. Xenosauridae. Pleurodont, solid teeth. Anterior part of tongue 



retractile. No osteoderms on the body. 

 Mexico, p. 536. 



Fam. 4. Zonuridae. Pleurodont. Tongue short, not retractile. With 



osteoderms at least upon the skull, where they 

 roof in the supratemporal fossae. African 

 sub -region, p. 536. 



Fam. 5. Anguidae. Pleurodont, solid teeth. Anterior part of tongue 



emarginate, retractile into the posterior por- 

 tion. Osteoderms on body and head, roofing 

 over the supratemporal fossae. Limbs mostly 

 reduced. America, Europe, India, p. 537. 



Fam. 6. Helodermatidae. Pleurodont, lower teeth grooved, with poison- 

 glands. Tongue bifid. Osteoderms tiny. 

 Postfronto-squamosal arch absent, p. 540. 



1 P. Ac. Philad. 1864, p. 224, and P. Amer. Ass. xix. 1871, p. 236. 



2 Ann. Nat. Hist. (5) xiv. 1884, p. 117. 

 VOL. VIII 2 L 



