INTRODUCTION

North of the continent of Australia lies the second largest island in the world, usually called New Guinea. The western part of it belongs to Indonesia and is nowadays called lrian Jaya. It is divided into a northern and a southern half by a large range of mountains. The southern part consists of a vast lowland through which two large rivers, the Digul and the Islands River flow. They descend from the mountains in the north to empty themselves into the Arafura Sea. Between these two large rivers many other rivers are found which originate in the swamps and also