330 DR. H GADOW ON EVOLUTION [Mar. 20, 



conuting these also the total sum would be 8 to 10 as stated by 

 Boulenger, scarcely 10-12 as described by Gliiither. 



Tibia with only 2| rows of scutes. 



Femoral 2)0)~es from 19-22. 



Coloration. — Throat whitish yellow, with a faint blue tinge 

 across the middle. Collar black in the adult ! Chest and belly 

 black with many white specks on the sides of the body. The 

 thighs, legs, and the whole tail a,i'e uniformly reddish yellow in 

 the youngest forms and in the immature; in the adult the thighs 

 are blue-black and cheqiiered with white. The preanal i-egion is 

 blue ; the tail beneath is speckled dusky. 



Upper parts (youngest forms) : 3 pairs of thin stripes ; mid-field 

 broad and bviff. 



Immature : the 3rd pair of stripes is partly vanisliing on the 

 I'ump, so that field II. is merging into the buff of the mid-field. 



Adult : the first pair of stripes begins to be cut up by the 

 encroaching black of field I. and by the black of the lateral field. 

 The result is a light brown or buff ground-colour, with only one 

 pair of pale stripes, and mottled with black on the sides of the 

 body. 



The al)sence of light spots in the fields and in the vanisliing 

 stripes constitute a I'emarkable pattern in this lai-ge and com- 

 pletely isolated kind of lizard. 



Cnemidophorus gularis Baird. 



The collar is composed of several rows of large scales, and the 

 jjosterioi' mai-gin of the collar is formed entirely of large scales, 

 without granules. The posterior side of the foi-earm is covered 

 with one or more rows of large polygones or scutes, instead of 

 granules ; 6 pale stripes persist as unbroken lines. The dark 

 fields are at first spotless, but soon a row of pale, mostly whitish 

 spots appeal's in the first and second fields, without bi'eaking up 

 these fields (text-figs. 69 & 70). 



It is not easy to abstract a satisfactory, fui'thei' definition from 

 Cope's writings of what he undei'stood by his C. gularis gularis. 

 The femoi'al scales are said to be in 6-8 rows. The femoral pores 

 are stated, in the key, to vary from 18-23, but in the text 

 specimens with less than 16 are mentioned. The fi'enocular 

 " occurs occasionally." The chest of the males is black, while the 

 scales of the belly are margined Avith black ; there are light spots 

 on the flanks below the first stiipe. 



Amongst an apparently large number of sjiecimens from 

 Chihuahua Cope mentions some, distinguished by him as G. g. 

 gularis ohsoletus, with wider and veiy obscure sti'ipes, and with 

 small obscure spots in the fields. Some of these specimens were 

 the largest of the collection. In others, including " a good many 

 small specimens," the sti'ipes were wider, and the field-spots 

 enlarged so as to be confluent occasionally with the light stripes. 



