TEIID LIZARDS OF THE GENUS CNEMIDOPHOrtUS 159 



NEVADA. — AViishoe County {ii,(ii' head of I* iJKt ik'kI L^tJx\'^ Stan- 

 ford). 



TIr'I'c are many locality rerortls for s[)('(inR'n.s with a ventral 

 coloration which may be interpreted as intermediate between the 

 dark and li<:ht extreme. Series of specimens from these localities 

 are so varied that some examples may be identified with one extreme 

 and some with the other, even in the adult stages. The list of these 

 localities folloAvs : 



ARIZONA. — Cochise County {Faivhanl\ Stanford); Pinal 

 County {16 miles west of 3Iia?ni, Taylor) ; ]Molun e County 

 (M.V.Z.U.C.) : Pima County {Tucson. A.M.N.H.) : Yuma County 

 {Yuma, r.S.X.M., Taylor). 



CALIFORNIA.— Imperial County {Pilot Knoh, :M.V.Z.U.C.) ; 

 Inyo County {Argiis Range^ U.S.N.M. ; Coso Maimtains, U.S.N.M. ; 

 Emigrant Cangon. F.M.N.H. : Grags at fJJJOO feet, Kcarsarge Pass, 

 M.V.Z.U.C: Laws, M.V.Z.U.C: Long Pine, U.S.N.M.; Panamint 

 Mountains,^lX:L.Y.C\ ^VU<1 Rose Cangon, M.V.Z.U.C); Mono 

 County {Benton, M.V.Z.U.C.) ; Riverside County {Palm Springs, 

 M.V.Z"!U.C.) ; San Bernardino County {Llorn Mine, M.V.Z.U.C). 



NEVADA.— Elko County {(Uirlin, U.S.N.M.) ; Humboldt County 

 {Big Creel- Ranch, ]\I.V.Z.l\C.) ; Washoe County {Xcar head of 

 Pgramid Lake. Stanford; ^Vadslcorth, U.S.N.M.). 



NEAV MEXICO.— Ostero C\)unty {Alani»g<>rdo, A.M.N.H.); 

 Siei-ra County {Elephant Butte Dam, Taylor). 



TTAH.- Beaver County {Bearer Creek, A.M.N.H.) ; Washington 

 County {Bellevue, A.M.N.H.). 



The areas from wliich these "intermediates" have been taken are 

 not confined to a definite point or line of contact between the two 

 diverging extremes, as will be seen from the list, and the common 

 appearance of both darker and lighter forms over most of the Great 

 Basin makes it impossible to recognize melanostethus as even a dis- 

 tinct subspecies. It merely represents the extreme development of 

 the tendency for the black pigment in the coloration to concentrate 

 ventrally. instead of dorsally. which is so characteristic of many of 

 the populations of tiiese whiptails in the most extensive sandy areas. 



A southeastern form from Parras. Coahuila, was described as a 

 species, variolosus, by Cope (189'2. p. 30). but it was reduced to sub- 

 specific rank under texsellatu.s by the same autlior in 1000. and in 

 1906, Gadow completely synonymized it with melanostethus. The 

 most striking feature atti'ibuted to rariolosus was the absence of 

 stripes. If it were not for the fact that certain specimens of 

 tessellatus from Smith Island (Gulf of California), Chihuahua. 

 Arizona, Texas, Utah, and otlier places, also show early tessellation 

 and lose nearly all traces of longitudinal ari'angement in the dorsal 

 nmrkings, such a character might have proved of value. The type of 



