93 



PHRYNOSOMA OnBlCVLARE.—Herna)idez. 



Plate XII. 



Characters. Head short, triangular; snout rounded; lower jaw without spines; 

 the three posterior labial plates large and elevated; nostrils open at the anterior 

 extremity of the superciliary ridge; a pointed tubercle in front of the meatus of 

 the ear; abdomen covered with smooth scales; femoral pores fifteen, very distinct. 



Stnontmes. Lacerta orbicularis, Hernandez, Nov. Plant. An. Mex., p. 67. 

 Agama orbicularis, Merrem, Versuch eines Syst. der Amphib., p. 53. 

 Phrynosoma orbiculare, TVagler, Naturlich. Syst. der Amphib., p. 146. 

 Phrynosoma orbiculare, Wiegmann, Herp. Mex., pars i. p. 53, tab. viii. fig. i. 

 Phrynosoma orbiculare, Dumeril et Bibron, Hist. Nat. des Rept., torn. iv. p. 381. 



Description. The head is short, triangular, the snout rounded, but less so than 

 in the last species, and covered in front and on the vertex with small polygonal 

 plates, and a few small tubercles on the occipital space. The rostral plate is very 

 small, sub-pentagonal; the nasal plates are single, circular, very narrow, and 

 surrounded by five or six polygonal scales. There are about ten small, quadri- 

 lateral, very narrow, superior labial plates, which do not extend as far as the angle 

 of the mouth, where their place is supplied by small granulations; the inferior 

 labial plates are similar to the superior in size and number, except the three or 

 four posterior, which are larger, and behind them is placed a conical pointed 

 tubercle at the anterior and inferior margin of the meatus of the ear. The 

 inferior and lateral border of the lower jaw presents an horizontal range of eight 

 large quadrilateral plates, instead of spines, as in the cornuta; these increase in 

 size towards the angle of the mouth, and being slightly elevated in their centre, 

 give a festooned appearance to the inferior and outer margin of the lower jaw; 



