

hp:rpetology of porto rico. 



619 



slightly differentiated at the lower end, but the difference between the 

 two forms is neither constant nor well marked, and is at best an 

 average one. 



The same remark holds good with regard to the preanal plates. In 

 all our specimens of A. alboguttata a smaller but well differentiated 

 plate is located on either side of the two posterior plates and a similar 

 one in front of the anterior plate, but this arrangement is also frequent 

 in A. exul, though not nearly universal. 



There is an average difference between the two forms in the width 

 of the plates on the upper arm. In A. eooul they are considerably 



70 «n I 72 



Figs. 07-72.— Ameiva alboguttata. H X natural size. 67, top of head; 08, side of head; 69, under- 

 side of head; 70, dorsal view of fore leg; 71, dorsal view of hind foot; 72, preanal plates. No. 29368, 



U.S.N.M. 



wider as a rule, especially the upper ones, while in A. alboguttata they 

 are usually comparatively narrower, with a tendency to decrease in 

 size gradually at the upper end, but intermediate and identical speci- 

 mens are not uncommon; thus in No. 29372, from Mona, and in 27146, 

 from Arecibo, Porto Rico, the relative size of the plates as well as 

 their relationship to the ones on the lower arm are exactly alike. 



As to any distinction derived from the entire separation of the plates 

 on the upper arm from those on the lower arm, or their more or less 

 apparent continuation, there is absolutely no difference in the two 



