ABSTRACT
An incomplete mandibular fragment of a cebine monkey from an early Holocene Haitian cave deposit adds to the small but growing list of fossil Antillean primates. The jaw is of the correct size to belong to the same taxon as the partial maxilla of "Saimiri" bernensis from the Dominican Republic. Both finds probably represent a single species whose proximate ancestry lay closer to Cebus than to Saimiri, although more evidence will be required to substantiate this. No close relationship of the Hispaniolan fossils to the Jamaican platyrrhine Xenothrix is indicated. How monkeys managed to penetrate the West Indies is a biogeographical puzzle of the first order. Geographical vicariance events, island-hopping, and purposeful or inadvertent introduction by humans seem rather implausible devices. On the whole, long-distance, over-water rafting from the Americas remains the most likely mechanism for past land vertebrate immigration into the Caribbean.