13. PHRYNOSOMA 367 



b*. Several (three or more) longitudinal series of en- 

 larged, pointed gular scales on each side; a series of 

 very large spinose plates below the lower labials; 

 head-spines large. 



cc. A long spine just behind the broad subrictal spine 5 

 head plates of adults mostly yellow, sparsely dotted 

 with brown. 



dd. Head-shields larger centrally, convex and almost 

 smooth. 



P. b. blainvillii. p. 388. 



dd'. Head-shields nearly equal, flat, with numerous 



ridges and granulations. 



ee. Largest spinose gulars and scales on chest 

 smooth 5 head deeper; occipital spines more erect. 



P. b. frontale. -p. 395. 



ee'. Largest spinose gulars and scales on chest 

 keeled 5 head less deep; occipital spines more hori- 

 zontal. 



P. cerroense. p. 401. 



cc*. No spine, or a very small one, behind the broad 

 subrictal; head plates of adults chiefly black or dark 

 brown with yellow edges. 



P. coronatum. p. 403. 



a'. Nostrils opening well above the lines joining the supra- 

 orbital ridges with the end of the snout; a series of very 

 large shields below the lower labials; gular scales small, 

 equal or with one row of enlarged scales on each side. 



bb. Occipital horns four (two on each side). 



P. solare. p. 406. 



bb' Occipital horns two (one on each side), 

 ccc. Peripheral fringe of elongate scales present. 



ddd. Peripheral fringe of one series of small spines; 

 femoral pores six to 12; no narrow dark median 

 dorsal line. 



