364- 3. IGUANID.^ 



in its habits than S. magister, a fact that determines its 

 local distribution, for trees on the desert are confined to the 

 larger water courses, the higher elevations on the moun- 

 tains, and the bottoms of the canyons. Near Tucson Scelo- 

 forus clarkii occurs along the Santa Cruz River and Rillito 

 Creek, following the tributaries of the latter into the can- 

 yons which they have carved out of the south slope of the 

 Santa Catalina Mountains. In the lower part of Sabino 

 Canyon I observed several individuals among the trees and 

 bushes with Cnemidofhorus gularis, and they seemed quite 

 as willing when frightened to take refuge beneath the stones 

 that strew the bottom of the gorge as to run up the trees. 



"The stomach contents of but one specimen was examined. 

 It consisted entirely of insects (one caterpillar and the re- 

 mains of several beetles)." 



Genus 13. Phrynosoma 



Phrynosoma Wiegmann, Isis, 1828, p. 367 (type, orbicularis). 

 Batrachosoma Fitzinger, Syst. Rept., 1843, p. 79 (type, coronatum). 

 Anota Hallowell, Proc. Acad. Nat. Sci. Phila., 1852, p. 182 (type, 



m'callii). 

 Doliosaurus Girard, U. S. Explor. Exped., Herpetology, 1858, p. 407. 



The body is very broad, greatly depressed, without 

 dorsal crest but usually with a lateral fringe. The head is 

 covered with small subequal scales, and bears bony spines 

 on the occipital and temporal regions. The tympanum is 

 either distinct or partially or entirely scaled. The dorsal 

 scales are very irregular in size and shape. Series of femo- 

 ral pores and one or more transverse gular folds are pres- 

 ent. The tail Is short. Males have enlarged postanal 

 plates. The genus is North American. About 20 species 

 and subspecies are known, 14 of which occur within our 

 geographic limits. 



