3 20 



CLASSIFICATION OF VERTEBRATES. 



teeth usually on pterygoids. Usually a large brightly colored sac beneath 

 the throat connected with the hyoid. Over 300 species known, all but a 

 few from the new world. Anolis includes the 'chameleon' (A caroli- 



nensis) of our southern states. Sce- 

 leporus contains the common lizard or 

 swift (S. undulatus) of the eastern 

 states north to Connecticut and Mich- 

 igan. The various species of ' horned 

 toad ' belong to Fhrynosoma. The 

 AGAMID^E replace the Iguanidae in 

 the eastern hemisphere. One hundred 

 and fifty species are known. These 

 all have acrodont teeth. Chlaniydo- 

 saurus includes the frilled lizard, C. 

 kingii, of Australia, with a broad 

 dermal fold or collar about the neck ; 

 Draco volans of Java has the ribs 

 greatly elongate, supporting a fold of 

 skin which acts as a parachute. 



SECTION III. BREVILINGUIA. 

 Tongue short, thick at base, no 

 sheath ; tip smaller and more or less 

 emarginate ; only slightly protrusible ; 

 pleurodont dentition; feet often re- 

 duced, two or none, the toes also fre- 

 quently reduced in number; but in 

 all cases pectoral and pelvic girdles 

 are present. Over 400 species are 

 known, but few of them inhabitants 

 of the U. S. The SCINCID.E have a 

 more or less snake-like body, covered 



with smooth bony scales ; tongue two-pointed. Eumeces, with teeth on 

 the palate, contains our blue-tailed lizard (E. fasciatus} ; and our weak- 

 legged ground lizard belongs to the genus Oligosoma. Scincus, with five 

 toes, contains the true skinks. In Seps the toes are three in number. 

 Scelotes has only hinder extremities, and in Anguis and Typhline legs are 

 lacking. Cyclodus. The ZONURID^: may be recognized by a finely scaled 

 groove along the side of the body. All except our ' glass snake,' Ophi- 

 saurus ventralis, belong to the old world. This species, which is limbless, 

 derives its common name from the brittleness of its tail. 



SECTION IV. FISSILINGUIA. Tongue long, slender, protrusible, 

 its tip deeply split ; eyelids well developed ; tympanic membrane visible ; 

 legs well developed. VARANID/E, pleurodont, tongue retractile into sheath ; 

 Varanus (Monitor] contains about 30 old-world species. LACERTID^E, 

 pleurodont, no tongue sheath; usually femoral pores; Lacerta, Tropido- 



FiG. 314. Green lizard, Anolis > 

 from Lutken. 



