16 BULI.ETIISr 15 4, UNITED STATES NATIONAL MUSEUM 



giilar folds, variable, small to large, enlarged series usually fonniiig 

 from 1 to G transverse rows, these often lai'ger centrally, but some- 

 times uniform in size, or enlarged medio-laterally ; post-mesoptychial 

 granules extremely minute, often hidden behind posterior gular fold, 

 but sometimes extending forward over the edge of that fold to 

 border the posterior row of enlarged mesoptychials. 



Back and sides covered by series of very fine granules, these 

 abruptly diifcrentiated from the much larger scales of the lower 

 surfaces and of the tail, ventral plates smooth, arranged in regular 

 longitudinal and transverse series, the former 8 to 12 in number, but 

 8 in all but munnus] preanals enlarged, differentiated, often 3, but 

 actually varying from 1 to 15 in number; anal slit transverse; 

 preanal spurs present or absent. 



Limbs Avell developed, moderately slender, usually strong; digits 

 5-5; each digit with a moderately curved, short, thickened claw; 

 subdigital lamellae small, transversely elongated, ridged, and in a 

 single series; supradigital scales larger, flattened, transversely 

 elongated, also in a single series, and often varying in size, particu- 

 larly on the hind foot; palmar surfaces of feet usually with 

 moderately enlarged, flattened scutes and granules, but sometimes 

 wath tubercules, particularly on the forefeet; a comb-like series of 

 more or less elevated and enlarged scutes usually forming the 

 external margin of the sole of the hind foot; brachials small to 

 large, usually in 5-10 rows; antebrachials, larger than brachials, 

 usually in 2 to 5 rows; brachials more or less continuous with 

 antebrachials at a point of contact; postantebrachium with small 

 granules, polygones, or scutes; upper surface of hind limb covered 

 b}^ granules similar to those on back; lower surfaces covered hy 

 scutes; femorals large, usually in 5 to 10 rows; tibials smaller or 

 larger, but in fewer rows, usually in 2 to 5 rows; femoral pores 

 present, 7 to 45 in number. 



Tail elongate, tapering, covered by small to large plates, these 

 forming distinct rings or annuli ; caudal scutes usually larger below 

 than above; lateral caudals usually more or less oblique; keels usually 

 present on dorsal and lateral caudals, but often absent from the 

 ventral scutes, especially anteriorly; lateral keels forming distinct 

 longitudinal ridges in certain species, but irregularl}- arranged in 

 others. 



In Cnemidophorus as a whole there is a remarkable amount of 

 geographic and ontogenetic variation in the color and color pattern, 

 particularly Avithin specific limits. It is true that some of the species, 

 such as those of the hyjjeryfJirus group, are striped throughout life, 

 and others, such as Ijacatus, nigHcolor, and catalinensis^ are spotted 

 or unicolor at all ages, but still other forms, such as gularis and 

 pcrplcxus^ may present both phases in the life history of an indi- 



