1906.] IX MEXICAN LIZARDS. 355 



7 left once ; 7 regular 3 times ; 8 to 9 irregular twice ; 9 regular 

 rows once. The average is consequently i-ather high. 



Tibia with 2|, mostly 3, rows of scutes. 



Femoral pores : ranging from 17/16 to 24/24 each once, 19 

 twice, 20/19 twice, 21/20 twice, 21/22 once, and 23 twice. 

 Average distinctly high, about 21. 



Size. — The 12 specimens range from 48 mm, to 138 and 140 mm., 

 the two largest being exceptionally fine males. A female of 90 mm. 

 and another of 69 mm. with eggs. 



Coloration of under parts. — The throat is yellowish, or clearly 

 pink. The collar of the female is whitish, sometimes with a blue 

 tinge on the sides ; in the medium-sized males quite black, but 

 pinlv like the chest in the two largest specimens. The chest and 

 abdomen change from whitish or leaden hues through mottled 

 blue to uniform blue-black in the males. This dark pigmentation 

 extends upon the arms and thighs, and partly upon the preanal 

 region. The under surface of the tail, at least its distal half, is 

 yellow to red. 



Pattern and coloration of upper surface. — These lizards start 

 with 3 pairs of stripes, of which only the 1st and 2nd are 

 whitish, whilst the 3rd is dull. Frequently there is a grey 

 central stripe, bordered with black. The fields are black, at first 

 spotless. Faint pale spots appear later. When the specimens 

 have passed about 70 mm. in length a few small, but sharply 

 marked, white-blue spots appear in the fields I. and II., and 

 stripe 1 is quite broken up into large black and white patches 

 Then stripe 2 is transformed into a series of round blue-white 

 spots, whilst stripe 3 fades away, leaving a very broad mid-field 

 region 2-2, which is green with blackish tiger-bars. Or, all the 

 stripes are broken up into rows of large white-blue spots, and 

 large tiger-bars run inght across the back from flank to flank, 

 producing a strikingly handsome pattern upon the otherwise 

 almost uniform dark olive ground (text-fig. 79 B, C). 



The continuation of stripe 1 on the hinder side of the thigh 

 breaks up early into pale spots, which disappear in the largest 

 specimens. 



The change of pattern from youth to age of these Cuicatlan 

 Lizards is absolutely different from that of C. inexicanus, and still 

 more from that of G. immutahilis and guttatus, while it agrees 

 with that of C. communis. G. hocourti, although geographically 

 the nearest so far as at present known, is structurally too different. 

 The same applies to the G. communis occidentalis with its out- 

 lying clan of Puebla. These Cuicatlan specimens differ much 

 more from those of Puebla than from those of Lagunas ; in fact, 

 the only diflerence is the frequent occurrence of a smaller- scaled 

 collar with a granular edge in the Cuicatlan s]3ecimens : but since 

 in some of them the collar-scales are as large as in those of 

 Lagunas, the importance of this character vanishes. The same 

 applies to the number of femoral rows and the pores, which varies 

 considerably, 



Proc. Zool. Soc— 1906, Yol. I. No. XXIV. 24 



