PHRYNOSOMA ORBICULARE. 95 



and terminates in a point, and is covered like the abdomen, but has only a few 

 spines at its basis and along its lateral margins. 



The anterior extremities are of moderate size, and covered above and in front 

 with large, elongated, rhomboidal, pointed scales, and with smooth scales below; 

 the fingers are five in number, slender, distinct, and each armed with a short 

 curved nail. The posterior extremities are but slightly larger than the anterior, 

 and are covered like them, both above and below, with the exception of a few 

 large spines scattered about the upper face of the thigh and leg; there are five 

 toes, long, slender, distinct, and each with a short curved nail. 



Colour. The head is dusky above, with a dark band between the orbit and 

 another along the posterior part of the occiput. The upper jaw is grey, the lower 

 white. The superior or long spines of the occiput are chestnut at their basis, and 

 black at the points; the others are dusky. The chin and throat is silver-white. 

 The body, tail and extremities above are coloured precisely as in the Agama 

 cornuta; below they are silver-white, with oblong or round spots on the thorax 

 and abdomen. 



Dimensions. Length of head to root of spines, 7 lines; of body, from head to 

 vent, 2^ inches; of tail, beyond the vent. If inches; of thigh, 9 lines; of leg, 9 

 lines; of tarsus and toes, 9 lines; total length, 4 inches 7 lines. 



Habits. I am not aware that the Phrynosoma orbiculare differs in its habits 

 from the Phrynosoma cornuta. 



Geographical Distribution. This animal is found in Arkansas and Louisiana, 

 and extends through Texas, Mexico, &c. to the Pacific ocean. 



General Remarks. There cannot be much doubt that this is the Lacerta 

 orbicularis, or Tapayaxin, of Hernandez; for his plate, which is tolerably good, 

 represents the scales on the thorax and abdomen as smooth. 



