320 PROCEEDINGS OF THE NATIONAL MUSEUM vol. iie 



the onset of summer rainfall. Scaphiopus hammondi, Crotaphytus 

 colJaris, and U. ornatus are darkly colored on lava. Similarly, 

 H. macvlata and S. graciosus are very light on white sand, but none 

 of these species exhibit geographically unique coloration. 



Scaphiopus bombifrons, Scaphiopus intermontanus, Eumeces obsoletus, 

 Salvadora grahamiae, Masticophis flagellum, Crotalus atrox, and 

 Crotalus molossus reach their hmit of range in the Zuni region. Sub- 

 specific intergradation occurs in Bufo woodhousei, Pseudacris triseriata, 

 Crotaphytus collaris, Sceloporus undulatus, Uta stansburiana, Urosaurus 

 ornatus J Eumeces multivirgatus , Pituophis melanoleucus , Hypsiglena 

 torquata, and Crotalus viridis. In certain cases, distributional patterns 

 may have been modified by climatic changes and the Colorado 

 Plateau-Basin and Range physiographic break located immediately 

 south and southeast of the Zuni region. The Plains Life Belt 

 apparently was eliminated during cool-wet periods of the Pleistocene, 

 and woodland environments were restricted during warm-dry intervals. 



Ambystoma tigrinum stebbinsi and A. t. utahense are synonymized 

 with A. t. nebulosum, Holbrookia inaculata ruthveni with H. m. ap- 

 proximans, and Phrynosoma douglassi ornatissimum with P. d. hern- 

 andesi. Diadophis regalis and D. dugesi are considered to be sub- 

 species of D. punctatus; the ranges of these forms and the western 

 limits of D. p. arnyi are clarified. Detailed accounts of variation in 

 A. t. nebulosum, Cnemidophorus velox, and southwestern and Mexican 

 Diadophis are presented. Environmental and ontogenetic variation 

 are given special emphasis, and a graphic method for illustratmg the 

 latter is offered in the discussion of E. multivirgatus. 



Addenda 



In preparing the account of recent environmental changes, I over- 

 looked an important paper by Leopold (1951b) containing a highly 

 pertinent summary of some nineteenth-century observations of Zuni 

 environments. Also instructive are two photographs (Leopold, 1951b, 

 fig. 1) of an area near Fort Wingate showing encroachment of sage- 

 brush on grassland between 1901 and 1946. 



The revised manuscript was completed in December 1961. Since 

 then, Smith and Wilhams (1962) have shown that the names Eumeces 

 multivirgatus gaigeae and Thamnophis crytopsis are conserved by ap- 

 plication of the nomen oblitum rule of the 1961 International Code 

 of Zoological Nomenclature. 



McCoy (1962) corrected Maslin's record (1959) of Crotalus viridis 

 viridis in Montezuma County, Colorado; he identified three specimens 

 from Mesa Verde as C. v. nuntius. Additional support for intergrada- 

 tion between the subspecies C. v. viridis, C. v. nuntius, and C. v. concolor 



