202 keptilia: lacertilia. — xxix 



extensible and retractile into a sheath formed by a transverse fold 

 at anterior extremity of posterior part, this sheath disappearing 

 when the tongue is drawn out. Premaxillary single ; dermal cranial 

 ossifications roofing over the temporal fossa; clavicle slender; limbs 

 present or absent, the shoulder girdle and pelvis always present; 

 no abdominal ribs ; bony plates underlying the scales ; vertical plate 

 on head present. Genera 7 ; species 45 ; in warm regions. 



a. Side with a conspicuous fold; limbs wanting or the hinder rudimentary; 

 body snake-like, the tail very brittle ; scales squarish rhomboidal, form- 

 ing straight series, in either direction Ophisaurus, 296. 



296. OPHISAURUS Daudin. (ocfiis, snake; aavpos, lizard.) 



589. O. ventralis (L.). Glass Snake. Joint-Snake. Green- 

 ish or brownish ; sides largely yellow, with narrow black streaks. 

 Dorsal scales in 14 rows or 120 transverse series ; 10 rows on belly ; 

 scales on back obtusely keeled, others smooth ; ear much larger than 

 nostril. L. 25. Wis. to Kan. and S. 



Family CXVI. IGUANID^E. (The Iguanas.) 



Tongue thick, villous, nearly or quite entirely fixed to the floor 

 of the mouth, and little if at all notched in front ; pupil round ; eye- 

 lids well developed ; scales various, those on head usually small ; 

 head generally with an enlarged interparietal scale ; teeth subequal. 

 Habits various, mostly insectivorous. A very large family of 50 

 genera and 320 species, swarming in the hotter parts of America; 

 a very few in the East Indies. 



a. Femoral pores absent; toes dilated or depressed, the distal joint narrower, 

 cylindrical or compressed, raised above the one before it; scales small 

 or granular ; cf with an inflatable gular sac ; tail long, not prehensile ; 

 lateral teeth tricuspid ; no sternal fontanelle ; tympanum distinct. 



Axolis, 297. 

 act. Femoral pores present; fourth toe longer than third; lateral teeth tri- 

 cuspid. 

 b. Head without spines ; no dorsal crest; occipital scale very large. 



c. Gular folds 2, the second denticulated; dorsal scales minute, uniform; 



caudal scales small ; tympanum concealed. . . Holbrookia, 298. 



cc. Gular folds none; tympanum distinct; scales keeled, equal; no crest. 



Sceloporus, 299. 



bb. Head armed with bony spines; body short, depressed; a large sternal 



fontanelle; scales unequal 1'iirynosoma, 300. 



297. ANOLIS Daudin. 



590. A. principalis (L.). "Chameleon." Grass-green ; head 

 brownish, the color changing at times in life to grayish, yellowish, 

 bronze, and black ; gular sac crimson when inflated ; head scales 

 large and rough; scales of body subequal, keeled. L. 6. Pine 

 woods, Tenn. to Cuba; common S. ; one of the most beautiful of 

 lizards. (A. carolinensis Cuvier.) 



