162 BULLETIN 17 7, UNITED STATES NATIONAL MUSEUM 



U.S.N.M. Nos. 59113 and 59119. The ventrals are usually smaller 

 than the largest supraoculars, but sometimes they are fully as large. 

 The supraorbitals may be large and distinct, with the third one on 

 each side somewhat larger than the others, or they may all be small 

 and rugose as in many old males, and scarcely distinguishable from the 

 other head plates. The suborbitals may or may not be separated 

 from the upper labials. The snout in the young and half-grown 

 specimens is as a rule much shorter and broader at the tip than seems 

 to be the case in adult males, where the heavy swelling of the tempo- 

 rals brings about a decided change in head proportion. Many speci- 

 mens show no trace of nuchal and dorsal ridges ; in others these ridges 

 are quite obvious. Furthermore, the middorsal area often presents 

 no enlarged scales at all; in other specimens one sees several rows of 

 pronouncedly larger scales along the nuchal and dorsal ridges. 



In many of the 211 specimens from San Michel (U.S.N.M. Nos. 

 74218-74428) there is a tendency toward the slight enlargement of a 

 single scale bordering the occipital anteriorly, very much as happens 

 to a much greater extent in dominicensis but with the difference that 

 here the preoccipital is not in contact with the supraorbitals. Not all 

 specimens from San Michel have a preoccipital readily distinguishable 

 as such, while occasional examples from other localities do have it. 

 This variation is paralleled by others in other characters, and nowhere 

 is it possible to find a stable variant of even subspecific importance on 

 the Hispaniolan mainland. The names haetianus and citrineUus have 

 been applied to individual variations, the occurrence of which is not 

 even localized. 



When actual segregation has taken place, as in the case of the 

 Gonave and Beata Island forms, a true differentiation may occur 

 with the fixation of the tendency toward local variation, which is 

 evident in this group of lizards. The Gonave Island lizard has a 

 longer head, while the canthi are relatively more nearly parallel, 

 instead of angularly divergent as in most of the mainland lizards. 

 I cannot find that the posterior occipital scales of Gonave Island 

 lizards are appreciably enlarged when compared with a large and 

 variable series of those from the mainland. The Beata Island lizard 

 is more distinct, possessing markedly larger dorsolateral granules and 

 much smaller ventral scales, a considerably longer tibia, fewer lamellae 

 under the fourth toe, and several other minor differentiating characters. 



Specimens examined. — As listed in table 28. 



