The Polyplacophora procured by the Musorstom 1-Philippines, 1976, Expedition were treated by the late Dr. Eugene Leloup (Leloup, 1981a). Only members of the genus Leptochiton Gray, 1847, were found, of which five species, all new to science, were described and illustrated. Since Leloup’s deeply lamented sudden death on July 31, 1981, more chiton specimens of the Musorstom 1 Expedition, as well as many samples of the Musorstom 2 Expedition, were sorted out and kindly entrusted to me by Dr. Philippe Bouchet (Paris), who participated in the 1980 Expedition. At the same time the types of Leloup’s new species were sent to me on loan. The results of a thorough study of this material are given here. Abbreviations. — BMNH = British Museum (Natural History), London; ITZ = Instituut voor Taxonomische Zoologie (Zoologisch Museum), Amsterdam;MNHN = Muséum National d’Histoire Naturelle, Laboratoire de Biologie des Invertébrés Marins et Malacologie, Paris.