198 BULLETIN 17 7, UNITED STATES NATIONAL MUSEUM 



scales in vertical rows, every fifth one of which is very slightly enlarged 

 to form very indistinct verticils. 



Dimensions: Snout to vent, 270 mm.; tail, 410 mm.; tip of snout to 

 ear, 53 mm.; width of head, 42 mm.; fore limb, 110 mm.; hind limb, 

 180 mm.; vertical diameter of tympanum, 10 mm. 



Color (in alcohol) : Head and body above and below slate-gray, 

 lightening to French gray on the snout and chin; tail drab to wood 

 brown, lightening beneath. 



Variations. — Since discussing the arrangement of the scales on the 

 snouts of the 9 lizards collected by Dr. Abbott, I have found the same 

 variability in 1 1 from Petite Gonave — eight have the nasals separated 

 from the rostral; two have them in contact with the rostral, and in 

 one individual both conditions are found. The frontal and prefrontals 

 are separated by two scale rows in seven of the Petite Gonave iguanas ; 

 in the remaining four by a single scale row. 



The femoral pores may be in one, two, or three series. There are 

 not more than 21 pores or less than 14. 



The scales of the dorsal crest usually blend gradually into those of 

 the nuchal crest, although in some cases the crests are discontinuous. 

 Counting the definitely distinguishable components of each, there is a 

 range of 38 to 58 scales in the dorsal crest, and 15 to 25 in the nuchal 

 crest. The sum of the scales in both crests is between 55 and 79. 



The tail verticils are exceedingly indistinct on all the specimens. 

 They can be made out proximally, however, and there are four, rarely 

 five, rows of scales between every two verticils. 



Relationships. — While Cyclura cornuta is undoubtedly related to the 

 Navassan Cyclura nigerrima, the two species seem perfectly distinct. 

 The former has much coarser scales on the body and tail, in sharp 

 contrast to the latter, which has exceedingly minute and practically 

 keelless scales on body and tail. The scales covering the top of the 

 head in the Navassan lizard are likewise smaller, while the rows be- 

 tween the enlarged prefrontals are more numerous, and the malar 

 scales are conspicuously smaller. The labial scales, however, are 

 fewer and larger in the Navassan form. 



Cyclura cornuta is very close indeed to the Mona Island form, 

 Cyclura stejnegeri. A real difference seems to exist, however, in the 

 number of scale rows between verticils on the tail, there being usually 

 only three such rows in stejnegeri, while four and sometimes five occur 

 in cornuta. 



Specimens examined. — As listed in table 34. 



