466 BULLETIN MUSEUM OF COMPARATIVE ZOOLOGY V. Geographic Differentiation in Anolis oculatus on Dominica By James D. Lazell, Jr. In 1956 Garth Underwood collected two series of Anolis ocu-latus in Roseau. Examining these and the specimens already in the Museum of Comparative Zoology he was led to suspect local population differences and therefore concluded in his report (1959) on the anoles of the eastern Caribbean that "clearly Dominica will require further careful examination. " In June of 1958 I was in Dominica specifically for the purpose of collecting some of the larger reptiles for the Philadelphia Zoological Gardens. At that time I collected a number of anoles at several different localities and noted striking differences in these series, apparently correlated with climate and elevation. This collection was donated to the Museum of Comparative Zoology and the following year I returned on behalf of that institution to determine what geographical differences existed and what the relationship of the apparent forms might be. In the course of eight weeks I collected over 500 specimens of this species from thirty localities; it now seems clear that in fact only one species is present but that it divides into four strikingly distinct geographic races. Anolis oculatus is clearly a member of the bimaculatus group of Lesser Antillean anoles. (I follow Underwood [1959] in treating it as a distinct species.) It averages much smaller than bimaculatus (adult males: 70-76 mm snout to vent — except in the upland race, which approaches bimaculatus with lengths of up to 96 mm ) , and possesses weakly keeled ventrals and a double row of enlarged, sometimes swollen, middorsal scales. Generally the scales are convex, particularly on the head and neck. All forms show caudal cresting in the adult males and in some this is pronounced. Males also have an extensible nuchal crest. Coloration and pattern vary widely within the species and furnish the principal basis for differentiation of the forms. The species as a whole shows a greater or lesser amount of spotting ; from this feature the trivial name is derived. The spotting con-sists of alternating primary and secondary vertical rows of light spots — generally three to five of each along each side of the animal. The primary rows have their spots accentuated by dark, often black, pigment areas in the adult males; these dark pigment areas may be borders on several primary spots, or dots
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