1903.] and Orthoycnetic Variation in Lizards, etc. Ill 



Mexico ; C. deppei, Wiegm ; C. guttatus, Wiegm ; C. striatus ; C. mexicanus, 

 Peters ; C. bocourti, Boulenger. 



The number of the small granular scales on the back varies extremely. 

 Counted in transverse rows across the body, such a row contains in 

 C. deppei from 93 to 150 and more, regardless of sex and age; in 

 C. guttatus from about 100 to 180. The relative size of these scales is 

 consequently not a trustworthy character. The number of supra-ocular 

 plates is normally 4 in C. mexicanus and C. bocourti, but sometimes the 

 most posterior plate is very small, separated from the rest, or absent. 

 In C. guttatus and C. deppei the number is normally reduced to 3. 



The posterior edge of the collar on the neck is abrupt, being formed by 

 the enlarged scales themselves, in C. bocourti, while in C. guttatus and 

 C. striatus the edge is formed by one or more complete series of granules. 

 In the majority of adult C. deppei there is one complete series of 

 granules ; several females show one granule between each scale, and in 

 others the collar ends abruptly without granules. Lastly in C. mexicanus 

 this character breaks down completely, independent of age and sex. 



Number of enlarged scales on the forearm : 2 rows in C. deppei and 

 C. guttatus 3, rarely 2 in C. bocourti, 3 in C. mexicanus. 



Slightly enlarged granules or scales on the posterior aspect of tliefoi'earm : 

 the whole posterior surface is uniformly granular in C. guttatus ; a few 

 slightly enlarged scales near the elbow in some C. deppei ; a cluster 

 nearer the hand, almost imperceptible in C. striatus ; several slightly 

 enlarged rows in some C. deppei ; several long rows of distinctly 

 enlarged scales in C. mexicanus and C. bocourti. 



A separate cluster of slightly enlarged granules or scales occurs on the 

 hinder surface of the upper arm (so-called postbrachials) near the elbow, 

 separated from the large scales by small granules ; C. guttatus some 

 C. striatus and some C. deppei. No such cluster occurs in C. mexicanus, 

 bocourti, most deppei and some striatus. 



The enlarged scales which protect the thighs' anterior and inner surface 

 are arranged in several rows ; 6 7 in C. deppei (7), 8 or 9 in C. bocourti 

 8 or 9 in C. mexicanus , rarely 8, mostly 9 to 12 in guttatus and striatus. 



Number of rows of enlarged tibial scales : 2 in most C. deppei increasing 

 towards 3, remaining at 2 in other deppei, in striatus and bocourti ; 

 increased to 3 complete rows in some deppei, in guttatu*, some bocourti 

 and in mexicanus. 



The cluster of enlarged preanal scales is separated from the regular 

 ventrals by about half-a-dozeu short, transverse rows of small roundish 

 scales, so that there is a distinct break between anals and ventrals ; 

 C. guttatus and striatus. The preanal cluster is separated from the 

 veutrals by but few scales, which are arranged rather irregularly, and 

 are in size not so abruptly smaller than the ventrals, and they form a 

 narrow isthmus : C. deppei, mexicanus, bocourti. 



The variations in the number of femoral pores can be expressed 



