69 



PHRYNOSOMA DOUGLASSII.— i?e//. 



Plate XII. 



Characters. Head short, triangular, pointed and covered with tubercles, and 

 not spines, on the posterior part, nostrils open at the anterior extremity of the 

 superciliary ridge; body elongated, rounded, flattened, covered above with scales 

 and slightly elevated and pointed tubercles, below with smooth scales; femoral 

 pores, eighteen on each thigh. 



Synonymes. Agama Douglassii, Bell, Linn. Trans., vol. xvi. p. 105, tab. x. pi. 105. 

 Phr3'nosoma Douglassii, Wag., Versuch eines Natur. Syst. der Amph., p. 146. 

 Phrynosoma Douglassii, TVeig., Herp. Mex., pars i. p. 54. 



Description. The head is short, triangular, flattened above, with its frontal 

 vertical, as well as occipital regions, covered with closely imbricated polygonal 

 scales; two slightly elevated tubercles only are seen on the latter region. The 

 rostral plate is very small and triangular; the nasal plates are single on each side, 

 very thin, and surrounded by five or six small scales. The nostrils are lateral, 

 situated at the anterior extremity of the superciliary ridge, and are directed 

 upwards and a little outwards. The superciliary ridge projects horizontally over 

 the eye, more so than in any other Phrynosoma, and is covered with six large 

 superior orbital plates, and terminates posteriorly in a small tubercle, very slightly 

 pointed. The eye is small, sunken, black; the eyelids are equally moveable, and 

 covered with minute scales. There are ten superior labial plates, quadrilateral, 

 and all nearly of the same size; the inferior labial plates are seven in number, 

 quadrilateral, and larger than in any of the genus. Behind these labial plates, and 

 on the same plane, are four tubercles, slightly flattened and pointed, the posterior 



