INTRODUCTION Two years ago I found two specimens of a curious animal in a sample of coral sand from Curaçao. It superficially resembled the larva of priapulids, animals that are restricted to cold water. The condition of the specimens did not permit of a description and I did not succeed in determining the group to which the species could possibly belong. Later I happened to see a paper by Remane (1963) in which he gives a simple figure of "a not yet described animal from the sandy bottom of the Red Sea". I immediately recognized it as a relative of the species from Curaçao. Upon request Professor Remane informed me that he had fixed some specimens, but that these were lost. He had not found more material of the species and he had not heard of these animals being found at another locality. In his opinion both his and my material obviously belong to the same genus. Recently I found a number of additional specimens in another sample of coral sand also from Curaçao. In the present paper a preliminary description of this material is given. When I had finished my description I found some specimens of a much larger animal that may be the mature form of the described species. A short description of this interesting animal is added. I am indebted to Dr. P. Wagenaar Hummelinck, Utrecht, who kindly put a number of bottom samples from the Piscadera Bay (Curaçao) at my disposal. I also wish to thank Prof. Dr. A. Remane, Kiel (Germany), and Prof. Dr. R. P. Higgins, Winston-Salem, North Carolina (U.S.A.), for their information and advice. Tubiluchus corallicola n. gen., n. sp.