356 BR. 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, entirely granular forearm, and with only 6 femoral 

 rows) have become so diffei'ent from the typical C. communis of 

 Colima, that nobody could or would refer them to C. comrinmis, 

 nor to any of the gularis-^vo\\\i 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 why the Cuicatlan specimens should not 

 be grouped in the imm\itabilis lot : but, first, the collar, when large, 

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

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

 immutahilis or in guttatus, with thi'ee regular rows of femoral 

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

 pattern. Although in immutahilis and in guttatus the stripes 

 break up into lows of sj)ots, transverse bai-s 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- 

 Cuicatlan specimens ai-e considered as of the C. communis stock, 

 modified in the direction of the typical Tierra caliente species 

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

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

 gula7- is- communis and the immutahilis-de2)2Jei groups, but is the 

 terminal outliei- of the former. 



CnEMIDOPHORUS COMMU>fIS 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. 

 About 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 Avhich 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 lizaid. 



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

 according to the 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. 



Throat 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 numeious yellow, 

 small, and sharply defined spots, which ai-e 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 



