The Jenolan Caves are some seventy miles inland from Sydney and lie on the eastern side of the Main Dividing Range at an altitude of 2,600 feet. The surrounding district is rugged, rising in parts to more than 4,000 feet, and is composed of sedimentary and igneous rocks of Silurian age. The specimens which form the basis of the paper were all collected within a radius of five miles of the Caves House. It is a matter for comment that the native forms recorded belong, without exception, to the genus Megascolex, despite the fact that the material examined represents the fruits of much intensive collecting. Michaelsen, who visited the area in the summer of 1905, secured a single example of a Notoscolex, but apart from this, species of Megascolex only have been identified from the region. My best thanks are due to Dr. A. B. Walkom, Director of the Australian Museum, who placed the material in my hands for examination. Unless otherwise recorded, the specimens were collected by the late Mr. J. C. Wiburd, at one time Superintendent of the Caves.