THE LIZARDS 173 



The nineteen species of Ameiva are confined to trop- 

 ical America and the West Indies. Cnemidophorus, 

 with its sixteen species, is more extensively distributed. 

 Its members occur plentifully in the southern portions 

 of the United States, throughout Mexico, Central Amer- 

 ica and South America, though not in the West Indies. 

 The species are strictly terrestrial, living in dry, usually 

 sandy places, where they run with such rapidity they 

 appear like a mere streak to the eye. Hence, in many 

 parts of the United States they are called Race-Run- 

 ners, the name also originating from their habit of bask- 

 ing on sandy roads, and, when approached, of darting 

 ahead for a short distance, yet always keeping on the 

 road, a trait causing the reptile to look as if inviting 

 a race. 



Cnemidophorus gularis and C. tessellatuSj of the 

 western United States and northern Mexico, are inter- 

 esting from their transition in pattern from the young 

 to the adult stages. The young of both species have three 

 narrow, yellow longitudinal stripes on each side of the 

 body. When specimens of C. gularis grow older, a 

 row of bright yellow spots appears between each of the 

 stripes; thus, the mature examples are both striped and 

 spotted. The change of pattern is more pronounced 

 with C. tessellatus, as the stripes entirely disappear and 

 a bold, marbled pattern takes their place. The latter is 

 one of the largest species of the genus, often reaching 

 a length of a foot and a half. 



The Sand Lizard or Striped Race-Runner, 'C. 

 secclineatus, is the only species of its genus ranging into 

 the southeastern portion of the United States, whence it 

 extends westward to California and into northern Mex- 

 ico. It is common in South Carolina, Georgia and 

 Florida, haunting sandy roads or dry fields, where it 



