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Show 1906.] IN MEXICAN LIZARDS. 369 Two specimens in the Brit. Mus. from Bernalillo Co., N ew Mexico, 67 and 72 m m . in length, possess 7 complete white stripes, the central being zigzag, but there are white spots in the first and second fields. Under parts all creamy white ; throat without spots. Structurally they agree with C. perplexus. Humerus with 4 rows of large scales, femur with 6 or 7 rows ; anterior side of forearm and tibia with 3 rows; pores 18 and 19. Specimens from Pecos according to Brown :-Largest 64 m m . ; 7 stripes; pores 13-18, averaging 15 only. He remarks that a few of the scales (granules) of the posterior side of the forearm are sometimes a little enlarged, and that two of the specimens have " large scales on the edge of the collar " instead of granules. Brown therefore considers C. 2)erP^exus as a subspecies of C. sexlineatus. CNEMIDOPHORUS TESSELLATUS * Say. (Text-figs. 70 & 64 A.) Length of adult 80-100 m m . Humerus with 4 or 5 large rows (Brown, 4 to 7); femur mostly with 7, rarely with 6 or 8 rows. Pores, according to Cope, 17-21; according to Brown two specimens from Pecos with 24 and 25 ; fifteen specimens from Alamogordo. New Mexico, with 22-25, average 23. There is a variable number of stripes which tend to become destroyed by white field-spots. Throat and rest of under parts with sparse black spots. Range. From the Coast of California to Nevada up to 6500 ft., Utah, Arizona, N e w Mexico, Basin of Rio Grande and Pecos in Texas. Also in Lower California and on Cedros Island. The variations of the colour-pattern are enormous and seem to be progressive, bearing several striking analogies to those observed in the gularis and deppei groups. The successive changes, mainly as pointed out and figured by Cope, are as follows. It must be borne in mind that the individuals of local clans may stop short at any of these stages, cases of Eimer's " Genepistasis." The young start with 6 or more stripes ; the first and second of which break up into longitudinal spots, and a series of white lateral spots seems likewise frequent. White spots appear in the fields, and either join the white stripes, or they gradually break up the fields transversely. This may result in the formation of * CNEMIDOPHORUS GRAHIMI Baird & Girard. Based upon two specimens from between El Paso and San Antonio in N e w Mexico; two other specimens reported from Jule Canon on the Staked Plain of Texas. According to Cope, C. stejnegeri (which itself is synonymous with C. tessellatus) differs from C. grahami in coloration only. If this were the case, the latter would also belong to the tessellatus-gvou]), most likely to C. perplexus, with which the pattern of colour agrees very well. Possibly the grahami specimens have somewhat enlarged scales forming a central cluster on the mesoptychium, as is not uncommon in C. tessellatus, e. g., from San Diego, and this feature has been exaggerated in fig. 117 of Cope's work. The figures on pi. 37 of the Mexican Boundary Commission are too fanciful to be considered. A.E.Brown records one specimen from Pecos, Texas, with 21 pores, " almost identical with C. sexlineatus in scale characters." |