9. HOLBROOKIA 169 



Genus 9. Holbrookia 



Holbrookia GIRARD, Proc. Am. Assoc. Adv. Sci., Vol. IV, 1851, p. 200 



(type, maculata). 

 Cofhosaurus TROSCHEL, Arch. f. Nat., 1850, (1852), p. 389 (type, 



texanus) . 



This genus contains a number of lizards similar to Calli- 

 saurus but with the ears hidden under the skin. The head, 

 rounded when seen from above but pointed in profile, is 

 covered with irregular plates, the largest of which is the 

 interparietal. The labials are produced laterally, and are 

 strongly imbricate. There is no ear-opening. The dorsal 

 scales are very small and nearly uniform. There are no 

 fringes of movable spines on the digits. Long series of 

 femoral pores are present, as are one strong and one or more 

 weak gular folds. Males have enlarged postanal plates. 



SYNOPSIS OF SPECIES 



a. Smaller ; tail cylindric, shorter than head and body, with- 

 out black bars below. 



b. Tip of longest toe usually not reaching eye when 

 carried forward; tail sometimes shorter than head and 

 body ; frontal scales sometimes smaller. Arizona and 

 Northern Sonora. 



H. m. approximans. p. 170. 



b . Tip of longest toe usually reaching to or beyond eye; 

 tail longer than head and body; frontal scales some- 

 times larger. Southern Sonora and Sinaloa. 



H. elegans. p. 175. 



* Larger; tail flattened, longer than head and body, with 

 black bars below. 



H. texana. p. 177. 



