3. CTENOSAURA 69 



with gray. The ventral surface between the fore limbs is 

 black. The belly is grayish. 



Length to anus 128 186 217 220 224 



Length of tail 228 . . . 



Sr-.out to ear 26 +0 50 +9 53 



Snout to edge of fold. 40 59 75 71 76 



Highest dorsal spines 14 8 5 9 



fore limb 36 44 52 82 84 



Hind limh 55 96 98 101 129 



Base of fifth to end of fourth toe 33 45 46 50 ___ 



Remarks. — There is great variation in the height and 

 length of the dorsal crest and the point at which the en- 

 larged series of scales stops on the back. The size of the 

 large caudal scales also is very variable, as is also the extent 

 of the keeling on the scales of the limbs. The ground color 

 may be anything from a pale yellowish gray to a dark slaty- 

 brown, and the black markings vary in number, size and 

 shape. Indeed, the variation is so great as to lead one to 

 doubt the distinctness of the two island species recently 

 described. 



Ctenosaura insulana, based upon specimens from Ceralbo 

 Island, and Ctenosaura conspkuosa, from San Esteban 

 Island, have recently been described. With good series of 

 specimens from both these islands, and from San Pedro 

 Nolasco Island and the Cape Region of Lower California 

 before me, I am unable to detect any difference in propor- 

 tions or in coloration, or in the size of the spines of the 

 caudal whorls, or the height or length of the dorsal crest, 

 which are not fully covered by individual variation in each 

 locality. As regards the keeling and mucronation of the 

 scales on the leg and foot, the same is true, great individual 

 variation in the strength of the keeling and mucronation be- 

 ing found in all four localities. These specimens, therefore, 



