370 3. IGUANID.^ 



scarcely more than rudiments, occipitals nearly erect, last 

 temporal sometimes erect. Supralabials small but promi- 

 nent. Infralabials slightly larger than supralabials, and 

 continued farther back, becoming gradually spinose. Other 

 head scales small, irregular in size and arrangement, more 

 or less convex, and roughened with ridges and granulations. 

 Two groups of spines on neck, upper being larger. Back, 

 tail and upper surfaces of limbs with scattered, large, more 

 or less erect, keeled tubercular scales; between these, skin 

 covered with smaller scales and granules. Body with fringe 

 of one series of peripheral spines. Chest and belly and lower 

 surfaces of hind limbs and tail covered with small smooth 

 scales. Tympanum either naked or scaled. Long series of 

 from sixteen to twenty femoral pores on each side, almost 

 meeting medially. Males sometimes with enlarged post- 

 anal plates. 



The back is olivaceous, yellow, brown, gray or slate, 

 with two or four rows of dark blotches. These blotches 

 vary greatly in intensity but are almost always edged pos- 

 teriorly with white, gray or yellow. There is an indistinct 

 large dark blotch on each side of the neck. The coloring 

 of the tail is similar to that of the back. The ground color 

 of the head is very variable, as are also its darker markings. 

 The entire lower surface is white or pale yellow, sometimes 

 faintly mari^ed with gray or slate. 



Length to anus . . 30 46 64- 



Length of tail . 13 25 31 



^nout to ear . . . 8 11 15 



Width of head 9 12 18 



Length of occipital spine ^ 1 2 



Fore limb 14 20 24 



Hind limb 19 29 35 



Base of fifth to end of fourth toe Syi 9 It 



