1897.] LIZAEDB OF IHB GENtJS SCELOPORUS. 481 



Durango '. Giinther's S. omiltemanus I would regard as a strict 

 synonym of S. poinsettii, but for the blue throat of the female ; it 

 is at most a colour variety. Cope's S. torquatus cyanogemjs 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. ferrariperezi, Cope, prob- 

 ably, cannot be separated from the typical form. I have recently 

 received from Dr. Duges two specimens from Gruanajuato, sent 

 as S. melanogaster. One has the complete collar of the typical 

 8. torquatus, the other has it broadly interrupted as in the specimen 

 (without locality) previously referred by me to this form. I have 

 carefully compared the two latter specimens and find the agree- 

 ment absolute, both in coloration and in scaling. I specially 

 mention this on account of Giinther's statement that " Boulenger's 

 SceJoporus melanogaster is certainly a different form." 



All the specimens in division A of my table, and the second in 

 division B should be referred to the forma typica, 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. 



'Y&Y. poinsettii, B. & Gr. Supraoculars (and often frontals) more 

 or less broken up ; interparietal usually separated from the pos- 

 terior frontal, if this be distinct ; femoral pores 9 to 15. 



Hah. 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 Eio Grande, whilst the 

 var. poinsettii penetrates farther into Texas. 



2. SCELOPORtrS BULLEEI. 



Sceloporus bulleri, Bouleng. Proc. Zool. Soc. 1894, p. 729, pi. 

 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 



^ 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. 



