PHRYNOSOMAORBICULARE. 63 



The anterior extremities are large, 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 furnished 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 silvery-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, 2i inches; of tail, beyond the vent, H 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. 



