204 VERTEBRATE ANIMALS OF THE UNITED STATES 



A . pulchra Gray. Length i8o mm. ; tail 6 mm . ; color gray or brown 

 with 3 dark lines; abdomen yellowish: coastal region of southern 

 California. 



Family 6. Helodermatidae. — ^Large, thick-bodied hzards with 

 brightly colored bodies, covered with small bead-like tubercles; tail 

 short; poison fangs in the lower jaw: i genus. 



Heloderma Wiegmann. With the characters of the family : 2 species. 



H. suspectum Cope. Gila monster. Body 470 mm. long; tail 

 120 mm.; color black or purplish, with large, more or less transverse 

 pink or yellowish blotches: deserts of Arizona and New Mexico; the 

 only poisonous lizard in the country or the world. 



Family 7- Xantusiidae. — Diminutive, cylindrical hzards with very 

 short legs, and granular scales on the sides and back; belly covered 

 with plates; 3 folds of skin on the throat; eye usually very large and 

 without eyelids; pupil vertical: about 4 species; in desert regions. 



Xantusia Baird. With the characters of the family: 3 species in 

 the United States. 



X. henshawi Stejneger. Length 140 mm.; tail 85 mm.; color 

 blackish brown, irregularly marbled with cream-colored lines: southern 

 California. 



X. riversiana Cope. Length 175 mm.; tail 87 mm.; color gray or 

 brown, spotted with brown or black: San Nicholas, San Barbara and 

 San Clemente Islands. 



X. vigilis Baird. Length 85 mm.; tail 45 mm. ; color gray, yellow or 

 brown, speckled with brown: southeastern California; southern Nevada*; 

 common in and beneath fallen yucca trees. 



Family 8. Teiidae. — Elongated lizards with a deeply bifid tongue 

 and sometimes rudimentary legs: i genus in the United States. 



Cnemidophorus Wagler. Race runners. Body slender; tail long 

 and tapering; scales granular above, plated beneath: 7 species in the 

 United States. 



C. sexlineatus (L.). Swift (Fig. no). Length 250 mm.; tail 175 

 mm.; color dark brown, with 6 yellow stripes on the body; belly bluish or 

 greenish: Maryland to Florida; westward to Arizona; up the Mississippi 

 Valley to Lake Michigan and Nebraska; common towards the south; 

 remarkable for its swiftness. 



C. gularis Baird & Girard. Similar to C. sexlineatus , but with a 

 row of pale dots between each two stripes: Arkansas and Texas to 

 Arizona. 



C. tessellatus (Say). Length 450 mm.; tail 300 mm.; color dark 

 olive, with 4 to 7 yellow stripes in the young animal; back marbled 



