356 DR. H. GADOW OX EVOLUTIOX [Mar. 20, 



Thus it has come to pass that some of these Cuicatlan specimens 

 (those with very small 4th supraocular, small collar-scales, and 

 granular edge, entii-ely granular forearm, and with only 6 femoral 

 rows) have become so different from the typical C. communis of 

 Colima, that nobody could or would refer them to G. communis, 

 nor to any of the gidaris-^vow]} at all, if the specimens of Lagunas 

 and San Domingo were not known. The most reliable guide 

 happens after all, in this case, to be the colour-pattern. 



It may well be asked Avhy the Cuicatlan specimens should not 

 be grouped in the immutabilis lot : but, first, the collai-, when large, 

 is of the unmistakable gularis type ; secondly, when the number of 

 pores is decidedly high this feature is never associated, either in 

 immtttabilis or in guttatus, with three regular rows of femoral 

 scales extending down to the knee ; thirdly, the evolution of the 

 pattern. Although in immutabilis and in guttatus the stripes 

 break up into rows of spots, transverse bars are quite unknown, 

 while again in C. mexicanus, of Oaxaca, in spite of its tiger-bars, 

 this mode of breaking up the stripes and the appearance of new 

 white spots in their place are equally unknown. 



Consequently it is not due to chance that the Laguna- 

 Cviicatlan specimens are considered as of the C. communis stock, 

 modified in the direction of the typical Tierra caliente species 

 C. immutahilis and guttatus. In short the var. australis, although 

 in many respects intermediate, is not a true link between the 

 gulay^is-communis and the immutaoilis-depj^ei groups, but is the 

 terminal outlier of the former. 



Cnemidophorus communis bocourti Blgr. (Text-fig. 80.) 



Diagnosis. — 4 supraoculars. Collar composed of large scales, 

 which form the edge. Humerals 6 ; femorals 5 to 6. Posterior 

 side of forearm with some large polygones or scutes. Pores 15-18. 

 Abovit 12 rows of small yellow spots on red-brown ground-colour. 

 Length about 100 mm. Oaxaca. 



Unfortunately the three type-specimens in the British Museum 

 are without satisfactory localities. One is from " Mexico," the 

 others were got by " Cumming, California," a locality which may 

 safely be dismissed as erroneous. In 1 902 I caught three speci- 

 mens in the outskirts of the town of Oaxaca, indistinguishable 

 from the types of this well-marked lizard. 



Boulenger gives the number of femoral rows as 8 or 9, but 

 according to tlae plan adopted throughout this paper, i. e. counting 

 from the row nearest the poi-es to the largest row on the anterior 

 side of the thigh and not beyond, there are only 6 or 5 rows. 



Thi'oat and collar are pale with a greenish tinge ; rest of under 

 parts, including .thighs, blue-black, mottled with bluish-white 

 scales. General colour above warm reddish brown, turning into 

 olive towards the shoulders and the neck ; with numerous yellow, 

 small, and sharply defined spots, which are arranged in about 

 12-14 longitudinal rows. These spots are most numerous on the 

 rump, extending also upon the root of the tail and over the 



