78 



most distinguishing features between _C. dixoni and _C. tesseiatus ; the 

 most important differences are ecological. The geographic distribution 

 and habitat of _C. dixoni in west Texas is discussed in detail, and the 

 sympatric ecological relationships with _C. tesseiatus and its generating 

 species is discussed. Two pattern classes (A & B) of _C. dixoni are re- 

 cognized; _C. tesseiatus F from Hidalgo County, New Mexico, is referred 

 to _C. dixoni "B^ (The author of the present review has important com- 

 ments on this paper in the introduction). 



206. — . 1977. Some recent changes in the herpetofauna of the north- 

 ern Chihuahuan Desert, jn TRANSACTIONS OF THE SYMPOSIUM ON THE 

 BIOLOGICAL RESOURCES OF THE CHIHUAHUAN DESERT REGION, 

 UNITED STATES AND MEXICO. Wauer, R. H. and D. H. Riskind, 

 eds. Natl. Park Service Trans. &. Proceedings Series No. 3: 513-522. 



There has been an increase in Cnemidophorus tigris populations in 

 the Fort Stockton, Texas, area at the expense of _C. gularis and _C. in- 

 ornatus over the last several decades due to increased human-influenced 

 aridity. 



207. — . and 3. R. Dixon. 1973. Diet and feeding behavior of Teiid 

 lizards from Trans-Pecos Texas. SOUTHWESTERN NAT. 18(3): 279-289. 



Food items eaten and foraging behavior are discussed in detail for 

 Cnemidophorus exsanguis , _C. gularis, _C. inornatus , C_. tesseiatus E and 

 _C. tigris . It is concluded that minor differences existing between the 

 species in types and proportions of food items eaten could be important 

 in adverse times. Foraging behavior among sympatric species represents 

 differences in methods of obtaining food, and thus represents niche 

 segregation. 



208. Smith, D. D. 197^^. Population structure, growth and reproduction 

 of two species of Cnemidophorus ; one unisexual and one bisexual. HER- 

 PETOLOGICAL REVIEW 5(3): 77-78. 



Cnemidophorus exsanguis and _C. gularis were studied in Brewster 

 County, Texas. Individuals of the former species reached reproductive 

 maturity at the age of 10 months, but most females of the latter species 

 did not mature until their second potential reproductive season. Snout- 

 vent lengths and clutch size were directly proportional. Older females 

 of both species produced 2 clutches per year. 



209. Smith, H. M. and H. K. Buechner. 1947. The influence of the 

 Balcones Escarpment on the distribution of amphibians and reptiles in 



