494 



MB. G. A. BOTJI/ETiTGEIl ON THE 



[May 18, 



In the same year, I had to deal with the genus Sceloporus in the 

 second vohirne of the ' Catalogue of Lizards,' and, notwithstanding 

 the small material at my command, felt justified in uniting under 

 one species S. spinostis, horridiis, and chirJcii, which seemed to 

 agree in all respects save the number of femoral pores, viz., 7 to 10 

 in the first, 2 to 5 in the second, and 12 to 15 in the third ; and 

 this character served me in dividing the species into three forms or 

 varieties. 



Giinther, in 1890, went even further, and refused to accept the 

 varieties on the ground of a " want of agreement between the 

 number of pores and the distribution of the species." This is 

 partly due to his having mixed up two species under his S. spi- 

 nosiis (see '^. acanthinvs, p. 497). As a matter of fact, Giinther 

 never examined a Mexican specimen of S. sjnnosus with more than 

 13 pores, and the only two that possess more than 10 come from a 

 locality (Tampico) which is not physically separable fi'om Arizona 

 and Sonora, the home of S. mar/ister, to which form they un- 

 doubtedly belong. 



In 1893, Stejneger discovered differences in the scales in front 

 of the ear by which he proceeded to divide the S. spinosiis with 7 

 or more pores into as many as five species, viz., S. s^niwsiis, 

 S. houlengeri, S. clarkii, S. JJoridanus, and aS'. magister. I will now 

 examine the value of these supposed species. 



1. S. houlengeri is based on specimens from Presidio, near 

 Mazatlan, believed to be distinguished by small, comparatively 

 short and broad auricular scales, and a very broad interparietal. 

 As the British Museum possesses 7 specimens from the same 

 locality and collector, I am in a position to dispose at once of this 

 supposed species by figuring (fig. 2) the ears of two specimens, 

 one of which (a) agrees with Stejneger's figure, the other (6) 

 approaching the type of /S. sjjinosus as figured by Bocourt (c), and 



Fig. 2. 



h. o. d. 6. 



Auricular scales of Sceloporus spinosus. 



by giving the following measurements of the interparietal in four 

 specimens each of S. spinosus, S. houlengeri, and 8. clarhii; the 

 first figure indicates the length, the second the width : — 



S. spinosus . 

 S. houlengeri 

 S. clarkii. . . 



.5 : 4, 5:5, 4 : 4^, 4 

 5 : 5, 5:5, 4:5, 

 4|:4|,4:4i,4:4, 4 



4^ 



:4. 

 : 5. 

 : 4. 



There is no difference whatever, in structure or coloration, by 

 which S. houlengeri may be distinguished from S. spinosus. 



