This study examined the question of whether a big island can be divided into many smaller islands with the same pattern of area-species curve as that of the complete island. To address this question, this study used data on the number and distribution of amphibians and reptiles on Puerto Rico and landbridge islands of the Puerto Rican Bank, which were fragmented from the big island about 10,000 years ago. In Puerto Rico, the data show correlations between the number of species and area available at different elevation levels and between species and area after removing effects of elevation. These patterns are different from the patterns of correlation between area and the number of reptiles and amphibians on 29 islands on the Puerto Rican Bank. The area-species curves of the elevationally and areally subdivided "islands" on Puerto Rico tend to have steeper slopes than the curves of the Puerto Rican Bank islands. Analyses of area and the number of those species on fragmented habitat islands at different elevations also indicated correlation between them. However, patterns of correlation seem not to be the same at each altitude. The slope of the area-species curve seems to decrease with increasing elevation levels. Other patterns of species distribution of Puerto Rico's herpetofauna are: there are linear relationships between the number of species and elevation, the number of species and distance from the coast, and the number of species and the species range areas. Multiple regression analyses of three variables: area, precipitation, and elevation, suggested that variation of species distribution in Puerto Rico is partly caused by interactions among these variables. Elevation plays an especially important role in explaining reptile and amphibian distribution. The rainfall variable had the least effect on determining herpetofauna diversity. The study results suggest that area-species correlation is a consequence of habitat heterogeneity on the island.