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Show 1897.] LIZARDS OF THE GENUS SCELOPORUS. 481 Durango 1. Giinther's S. omlltemanus I would regard as a strict synonym of S.polnsettll, but for the blue throat of the female; it is at most a colour variety. Cope's S. torquatus cyanogengs and S. torquatus mucronatus I also regard as synonyms of the var. poinsettii, as I find the degree of mucronation of the dorsal scales and the development of the nuchal collar to be subject to individual variation. S. melanogaster, Cope, certainly, and S. ferrariperezl, Cope, probably, cannot be separated from the typical form. I have recently received from Dr. Duges two specimens from Guanajuato, sent as S. melanogaster. One has the complete collar of the typical S. torquatus, the other has it broadly interrupted as in the specimen (without locality) previously referred by m e to this form. I have carefully compared the two latter specimens and find the agreement absolute, both in coloration and in scaling. I specially mention this on account of Giinther's statement that " Boulenger's Sceloporus melanogaster is certainly a different form." All the specimens in division A of m y table, and the second in division B should be referred to the forma tgpica, all those in division C, and the first specimen in division B to the var. poinsettii. The definition of the two forms may be given thus:- Forma typica. A series of transversely enlarged supraoculars : interparietal usually in contact with the posterior frontal; femoral pores 14 to 20. Var. polnsettll, B. & G. Supraoculars (and often frontals) more or less broken up; interparietal usually separated from the posterior frontal, if this be distinct; femoral pores 9 to 15. Hab. The range of this species extends over the greater part of Mexico, west of the Isthmus of Tehuantepec and east of Sonora and Sinaloa. The typical form is not known north of Laredo and El Paso in Texas, both localities on the Bio Grande, whilst the var. polnsettll penetrates farther into Texas. 2. SCELOPORUS BULLERI. Sceloporus bulleri, Bouleng. Proc. Zool. Soc. 1894, p. 729, pl. xlviii. fig. 3. Head-shields smooth ; frontal transversely divided, sometimes in contact with the interparietal, but more usually separated from it by the frontoparietals ; interparietal as long as broad or a little longer than broad, much larger than the parietals ; a series of four transversely enlarged supraoculars, bordered inwards by one series of scales and separated from the supraciliaries by one or two series of small scales; two canthal scales ; four or five pointed scales, a little larger than those in front of them, form a denti-culation on the anterior border of the ear. Dorsal scales much larger than ventrals, a little broader than long, keeled, mucronate and denticulate, the keels converging 1 It is not present in the type specimen figured by Baird and Girard, but I find indications of it in specimens from Duval Co., Texas. |