1906.] IN MEXICAN LIZARDS. 327 



{de2ypei within the sandy river-bed, guttattts in the wooded parts 

 near the same banks), and deppei only at Juanita which lies within 

 typical Savannah. 



I consider it safe to affirm that C. guttatus is an enlarged species 

 of 0. deppei, and that the striped or spotted condition of its upper 

 parts depends directly iijjon the amount and character of the 

 vegetation : stripes in the ojyen, spots in the more bushy, shrubby, 

 forest-like districts. 



GuLABis-Gvoxx^. 



If we consider the great number of specimens, about 210, 

 scheduled in the following pages, as one mass, their characters 

 show such a great amplitude of variation that the diagnosis of the 

 gularis-gvo\\Y> becomes extremely vague. 



Supraoculars 4. 



Collar composed mostly of at least one row of large scales, but 

 the edge may be formed by this row or entirely by granules. 



Frenocular present or alDsent. 



Size, from nose to vent from decidedly small to distinctly large, 

 i.e. from 60 to 140 mm. 



Humeral rows of scales from 3 or 4 or 5 to 8 or 9, either all 

 large when there are but few, or some larger than the rest, or all 

 small when there are many. 



Posterior surface of the forearm covered entirely with granules, 

 or, the other extreme case, with several long rows of transverse 

 scutes or plates ; every intermediate stage being represented, but 

 the granular type is distinctly exceptional. 



Femur with only 5 or 6 very regular rows, to as many as 

 8 or 9. 



Front of forearm and tibia with 2 to 3, or even with a 4th row 

 of scutes. 



Femoral pores from 15 to 26, without a break between these 

 rather rare extremes. 



The same wide uncertainty applies to the pattern and coloration. 



Under jxcrts. — At least this can be said : the throat is whitish, 

 often pink, never black ; but from collar to vent the undei- surface 

 may be whitish or yellowish, suffused with blue, or chequered blue 

 and black and white, or entirely blue-black, at least in the males. 



Upper surface. — All start with at least 6 pale stripes, and the 

 mid-field may be divided by an unpaired centre stripe or by a 

 4th pair of stripes. The fields may have light spots, whitish or 

 brown, or no spots. 



The stripes may remain entii^e throughout life, or they may 

 become ragged by confluence with neighbouring pale field-spots, 

 or by encroachment of black field-spots ; or the stripes may become 

 dull and fade away unless new whitish, bluish or yellow spots 

 develop within them. 



The fields, originally dark, may remain spotless, or white, bluish 

 or yellow or brown spots develop within them. These field-spots 

 remain ill-defined, or they turn into round, separate spots; or two 



