TEIID LIZARDS OF THE GENUS CNEMIDOPHORUS 125 



Sijstonatic Notes. — This form was dc'scribed in 1852 by Baird and 

 Girard, who separated it from the distantly rehited entities, tigvis, 

 marnwratus.) and (jrahani'i'i (all of Avhieh are now considered s}'!!- 

 on3^mous with tessellatus) on relatively insignificant characters. 

 After an examination of the type, it is not clear why these anthors 

 shonkl have written that this lizard has the "' general appearance of 

 grahamii,^'' for spots and reticulations are absent from its pattern. 

 However, the ground color is '' yellowish green " and there are 

 •' seven yellowish stripes extending from the occiput to the base of 

 the tail."' It is the presence of these stripes and the absence of field 

 spots that have served as the basis of its recognition until the present 

 time. The writer has found that both of these characters are insuf- 

 ficient. There is a complete transition from the unspotted to the 

 spotted phase; and the number of lines on the bod}^ varies from six 

 to eight, commonly being six and a fraction. Thus, it is found that 

 the hitherto recognized '* gularis " of the Sonoran region is identical 

 with ferple,('UR and that this whole population possesses character- 

 istics which make it a taxonomic entit}^, sufficiently separating it 

 from the closeh' related eastern and southern relatives, which are 

 sexJineatus and the true gularis. Because of intergradation with 

 these forms, chiefly in western Texas, perplexus is here given sub- 

 specific rank. Thus, the C. sexUneatus perplexus of this Avork is the 

 representative of the sexUneatus group in the Sonoran region of the 

 United States and Mexico. 



B}' the examination of specimens at the United States National 

 Museum, it is found that the numerous forms of C nemklophorus 

 described by Cope from southern Chihuahua are in reality intergrades 

 between gularis and pevplexus., and as such they are given places in 

 the synonymy of both subspecies. The detailed discussion of these 

 is given under gularis (see p. 104) . 



During the period of development perplexus., like giolaris, goes 

 through an intricate series of pattern stages, and while there is 

 considerable individual variation, the evolution is in all cases essen- 

 tially the same. The young are often unspotted, and in such, as a rule, 

 the appearance of spots in the lateral fields may be expected sooner or 

 later. In certain individuals and regions this phenomenon seems to 

 be retarded more than in others. At times the spotted phase is 

 transformed into a tiger-barred phase by the spreading of the spots 

 to form cross-bars with the stripes above and below them. This is 

 accompanied by a tendency for the dark ground color to also encroach 

 upon the longitudinal light stripes and to unite across them. Thus 

 the whole aspect of the pattern is changed, the emphasis being trans- 

 ferred from the longitudinal to the transverse. AVhen series are 

 examined it becomes impossible to separate one phase from another, 



