14 IGUAN1B.15. 



b. Scales on upper surface of snout keeled ; supraorbital 

 semicircles separated by one or two series of scales. 



Ventral scales small and feebly imbricate, the 



keels not forming continuous lines 20. Uneatopus, p. 39. 



Ventral scales large and strong!}" imbricate, 



the keels sharp and forming continuous 



lines 21. sac/rce, p. 40. 



III. Tail stronglj- compressed, with serrated upper edge ; a strong 

 fold across the throat. 



All the scales very small and keeled 22. vennicidatus, 



[p. 41. 



IV. Tail cylindrical ; dorsal and lateral scales minutely granular, 

 intermixed with scattered enlarged ones. 



Ventral scales smooth ; supraorbital semi- 

 circles in contact 23. Joysiana, p. 42. 



V. Tail subcylindrical or slightly compressed, seldom more com- 



pressed and with a slightly serrated trenchant upper edge '. 

 Dorsal scales, except in some cases those on the vertebral line, 

 not or but indistinctly larger than those on the flanks. 

 Digital expansions strongly or moderately developed, ;'. e. the 

 third phalange of the fourth toe is considerably broader than 

 the basal. 



A. Occipital scale at least as large as the ear-opening ; scales of 

 the supraorbital semicircles considerably enlarged. 



1. Tibia not measuring two thirds the length of the head (to 

 occiput). 



a. Occipital separated from supraorbitals. 



a. 22 to 27 lamellae under phalanges ii. and iii. of the 

 fourth toe. 



Scales of the supraorbital semicircles separated 



from each other by one or two series of 



scales, and from the occipital by one series. 24. caroluiensis. 

 Scales of the supraorbital semicircles separated [p. 43. 



from each other by two or three series of 



scales, and from the occipital by three 



series 25. cldorocyanus, 



[p. 44. 



/5. 18 lamellae under phalanges ii. and iii. of the fourth 

 toe. 



Occipital separated from supraorbitals by one 

 series of scales ; two or three large supra- 

 oculars 27. isohpis, p. 46. 



^ The species presenting this exception will iit once be recognized as not 

 belonging to division II. of this synopsis, bj the very small size ot the occipital. 



