85 



PHRYNOSOMA .—Wiegmann. 



Genus Phrynosoma. — Characters. Head short, rounded in front, bordered at 

 the sides and behind Avith spines more or less elevated; covered above with small, 

 polygonal, nearly equal sized plates. Nostrils lateral, near the snout, and 

 opening in the middle of the nasal plate; margin of external meatus of the ear 

 simple; tympanum visible but depressed. Throat with a transverse fold; body 

 short, oval, much depressed, with a dentated margin at the flank, and covered 

 above with trihedral tubercles, arising from among small imbricated scales; 

 neither spinal or caudal crest; extremities short, dentated at their borders; fingers 

 or toes iive to each extremity; a range of femoral pores, more or less developed; 

 tail hardly the length of body, and flattened at its base. 



Remarks. To Wiegmann, a celebrated herpetologist of Berhn, is due the merit 

 of having first pointed out the proper place for these animals in a systematic 

 classification. He removed them from the Agamse, and established the genus 

 Phrynosoma for their reception; and this he subdivided very naturally into 

 two sections, according to the mode of opening of the nostrils, the scales of the 

 belly, whether smooth or not, &c. &c. For further information on this subject, 

 consult the Isis, vol. xxi., or his Herpetologia Americana, a work I have read 

 with great interest. 



