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Show 318 DR. H. GADOW ON EVOLUTION [Mar. 20, collected a sufficient number of specimens, has its characteristic type : local clans of this small lizard :- m I. The Basin of the Rio Balsas.-There are no C. deppei to the north of it, even a few miles away from the river, and towards the south they are separated from their kindred by the densely wooded and elevated intricate mountains of the Sierra Madre del Sur, which is inhabited only by C. mexicanus var. bcdsas. The Balsas clan of G. deppei is noteworthy for the greater number of femoral scales, the average number of femoral pores, the black-blue colour of the whole under surface of the males, and the frequency of brick-red lateral fields; lastly, the poorly developed stripes on the mid-back. II. Tierra Colorada, to the south of the m a m ridge of the Sierra Madre, in Guerrero.-Average number of femoral scales, combined with the greatest number of pores; conspicuously 9-striped; adult males with two red bands on each side; throat not black ; collar, chest, and belly black. III. The Lowlands of Southern Guerrero.-Smallest number of femoral scales and pores ; 7-10 sharp stripes, while reddish bands are rare ; faint light spots in the first field are frequent and th* first stripe tends to break up into beads. Otherwise like Clan II., with which these southern specimens are geographically continuous. Note the difference in coloration of the three specimens from near Miahuichan, which lies on the southern outlying slopes of the Sierra, at an elevation of 1500-1600 feet, agreeing in this respect with Bincon at the foot of Los Cajones. The single Cajones specimen is the most blue-throated of the whole Tierra Colorada clan, and the Miahuichan specimens are remarkable chiefly for the partial extent of blue and black upon the throat. IV. States of Oaxaca and Vera Cruz.-Average, or great, number of femoral scales, with greatest number of pores. Preponderance of 10-11 stripes, with development of conspicuous white spots on the flanks and breaking up of the first stripe into beads. Absence of red bands; black on the throat is very exceptional, rare even on the collar. The structural characters vary too much for generalisation, as shown by 26 specimens, all from Tequesixtlan. The remaining 34 specimens came from eight different districts, and therefore afford no sufficient basis. Now, it is quite conceivable that in two geographically separate clans the following combinations might become universal. A. Supraoculars.'}; f emorals 7 ; pores 19; stripes 7 ; fields red ; throat and collar black. B. Supraoculars 4 ; femorals 5 ; pores 16; stripes 9-10; fields not red ; throat and collar wdiite. Either of such groups would be entitled to at least subspecific rank. But there is not yet any clan known with such a combination. As they stand, they must therefore be satisfied with |