In the following pages I intend to give some informations about the voyage, which my wife and I made in the Indo-Australian Archipelago from November 1909 till March 1910, as an introduction to the reports of the zoological collections made during that trip, which are published in this periodical. In 1909 the dutch Government granted for the first time a sum for the publication of a work on the Fishes of the Indo-Australian Archipelago by Prof. Max Weber and myself, of which the first volume has since appeared 1). A part of that sum, added to private means, enabled me to visit the Indo-Australian Archipelago in the interest of this work. I am glad of having an opportunity to express here my gratitude to the Minister of the Colonies as well as to the different officials in the dutch East-Indian colony for the interest they took in this voyage as well as for the liberal way in which they helped me everywhere. At the same time I wish to thank the Society for the Advancement of Scientific Research in the dutch colonies (Maatschappij ter bevordering van het Natuurkundig onderzoek der Nederlandsche Koloniën), that defrayed the expenses of the zoological equipment.