94 PHRYNOSOMA ORBICULARE. 



above these large plates, and below the labial plates, are two or three series of 

 small scales. The whole chin and throat are covered with nearly equal sized, 

 smooth, rhomboidal scales. 



The nostrils are near the snout, and open at the anterior extremity of the 

 superciliary ridge. The eyes are small and sunken, with the pupil black and the 

 iris dark grey. 



At the posterior border of the occiput is a row of spines, nine in number, 

 extending from the front of one meatus of the ear to the other; the U\o longest of 

 these spines are placed at the superior and posterior part of the occipital region, 

 and have a very small one between them; three other spines are placed on the 

 sides of the head, and decrease in size from above downwards: these spines are 

 formed like those of the Agama cornuta. The external meatus is large, rather 

 triangular, broader above, narrower below, with a small conical pointed tubercle 

 at its anterior and inferior margin. The neck is short, and contracted behind the 

 head. The chin is covered with small, equal sized, smooth, rhomboidal, imbricated 

 scales; the throat with similar scales, but smaller, and offers a transverse fold, 

 which ascends on each side of the neck, to cover an oblique depression in front of 

 the anterior extremities. 



The body is short, flattened, ecarinate, arched outwards at the flanks, and 

 covered with large, pointed, trihedral tubercles, interspersed among small rhom- 

 boidal, carinated scales and smaller tubercles. The vertebral line is covered with 

 three or four rows of small scales, and appears depressed, from the absence of the 

 larger tubercles that are found in other parts. On each side of the vertebral line, 

 and disposed in irregular rows, are scattered larger and pointed tubercles. The 

 flanks are bordered with a single row of spines, extending from the anterior to the 

 posterior extremity. The thorax and abdomen are covered Avith rhomboidal, 

 perfectly smooth scales. 



The tail is broad and flattened at its root, but suddenly becomes contracted. 



