14 IGUANID.E. 
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. lineatopus, p. 39. 
Ventral scales large and strongly imbricate, 
the keels sharp and forming continuous 
ities vas iaciaegrewd VASA Cee 21. sagre, p. 40. 
III. Tail strongly compressed, with serrated upper edge; a strong 
fold across the throat. 
All the scales very small and keeled........ 22. vermiculatus, 
[p. 41. 
IV. Tail cylindrical; dorsal and lateral scales minutely granular, 
intermixed with scattered enlarged ones. 
Ventral scales smooth; supraorbital semi- 
circles in contact, sc ceisseaeu see rau ae 23. loysiana, 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, 7. ¢. 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. Oceipital separated from supraorbitals. 
a. 22 to 27 lamelle under phalanges 11. and m1. of the 
fourth toe. 
Scales of the supraorhital semicircles separated 
from each other by one or two series of 
scales, and from the occipital by one series. 24. carolinensis, 
Scales of the supraorbital semicircles separated [p. 43. 
from each other by two or three series of 
scales, and from the occipital by three 
BETIOS. aise yaaa an a dete tanta aes 25. chlorocyanus, 
[p. 44. 
6. 18 lamelle under phalanges 11. and ut. of the fourth 
toe. 
Occipital separated from supraorbitals by one 
series of scales; two or three large supra- 
OCUIALS). Sica cneancniaaaiaione eamadom 3a dat 27. isolepis, p. 46. 
1} The species presenting this exception will at once be recognized as not 
belonging to division II. of this synopsis, by the very small size of the occipital. 
