The present monograph has been drawn up chiefly from material collected by Dr. P. WAGENAAR HUMMELINCK, secretary of the Foundation for Scientific Research in Surinam and the Netherlands Antilles, during his trips to the Caribbean in 1936/37, 1948/49, 1955, 1963, and 1967. This collection comprises about 1500 specimens of Polyplacophora belonging to 21 species, among which 4 are new to science. As up till now no comprehensive work on the chitons of the Caribbean area has been published the author made it his task not only to draw up a report on specimens collected by Dr. HUMMELINCK but also to give a general review of all the species of Polyplacophora occurring in the Caribbean Province.