FROM TEXAS AND MEXICO. 131 



imens have a more bleached or faded appearance. The 

 lowest number of femoral pores on a side is eleven, the 

 highest fourteen. 



HOLBROOKIA TEXAN A TrOSCh. ,' B. & G. 



From Parras, Monclova and Saltillo, Mex. 



The femoral pores number from sixteen to seventeen on 



each side. 



.xol/i f t3QJo 1 juJ nn< 



HOLBROOKIA PROPINQUA B. & G., 1852. 



Guaymas. 



On four specimens the number of pores on a side varies 

 from eleven to fourteen. This species and those of Cal- 

 lisaurus and Uta do not belong to Dr. Palmer's collection. 



The longitudinal fold or groove immediately behind the 

 symphysis under the chin of the Ophidia is apparently 

 duplicated in the species of Holbrookia, Callisaurus, Uta, 

 and, probably, of Uma. That this peculiarity is accom- 

 panied by ability to enlarge the mouth opening by means 

 of separation of the branches of the lower jaw at their 

 junction is hardly possible. The rigid alcoholic specimens 

 at hand are not the best for deciding the question. Yet 

 it is certain that, in comparison with other lizards, there is 

 a decided lack of firmness and solidity in the symphysial 

 attachment which is very suggestive of its elasticity and 

 flexibility in the earlier stages of the species. The presence 

 of the fold seems to characterize a group of the Iguanidae 

 of close affinities in other respects. 



CALLISAURUS DRACONOIDES Blainv., 1835. 

 Cape St. Lucas, Lower Cal. ; Guaymas. 

 Pores varying from fourteen to sixteen on a side. 



9JQJ . -. ;irioifflij KP'f-- 



UTA STANSBURIANA B. & G., 1852. 



iTiDor JIT ssmvrafl) OBIC ZK JomjgjD o f i 



San Diego, Cal. 



Pores fifteen plus fourteen. T9 j M 



