parts on the face are more distinctively bald and the outside parts of the arms and legs are more clear; this suggests they are white-headed capuchin. Some specimens of C. versicolor seen in the market at Magangué‚ and probably captured in the lower Cauca River, show similar tendencies to the above, except that there is no increase in the dark pigmentation. Based on these observations and on various "intermediate" specimens from northern Colombia, it is possible that an investigation of the contact zone between the white-headed capuchin and white-fronted capuchin ultimately could show that these forms are conspecific, or that some species of white-fronted capuchin are actually more closely related to white-faced capuchins than they are to other white-fronted capuchins. Another critical zone for this analysis is an area in northeast Ecuador where C. aecuatoriales and white-faced capuchins are found, although neither sympatric distributions or intergradation have as yet been determined. Description Male white-fronted capuchins usually weigh an average of and the females an average of , although a male on Mirití-Paraná in Colombia weighed . This primate is usually maroon-white or palomino and creamy white. It has short fingers and an opposable thumb. Like other capuchins its premolars are large, and it has square-shaped molar with a thick enamel to help with cracking nuts. Below are descriptions of the known species for Colombia. Humboldt's white-fronted capuchin, Cebus albifrons, is found in eastern Vichada, close to the type locality, and was defined by von Humboldt using a tame animal maintained by humans (and a pig) in the village of Maipures. The original description of von Humboldt described an ashy gray animal with a black tail tip, characteristics that are not typical of any known population of white-fronted capuchin. The C. albifrons located three kilometers to the north of Maipures are very light colored animals with yellowish or reddish tones, very similar to the population of Arauca. Spix' white-fronted capuchin, Cebus unicolor is also very light colored with yellowish tones and was once thought to be a likely synonym of C. albifrons. One population of very pallid coloration is found in Arauca, the northern part of Boyacá and the eastern part of Norte de Santander and probably represents C. a. albifrons. The Río Cesar white-fronted capuchin, Cebus cesarae is very light in color and quite well-defined as a subspecies. "The cap is cinnamon or snuff-brown; median dorsal region, forearm and forelag