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. 

 CO. — A long spine just behind the broad subrictal spine; 

 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; head deeper; occipital spines more prect. 



P. b. frontale.— p. 395. 

 ee'. — Largest spinose gulars and scales on chest 

 keeled; head less deep; occipital spines rijore hori- 

 zontal. 



P. cerroense. — p. 40 1 . 

 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. 

 '. — 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. 



