None. Begins: "During the preparation of a monograph on the phylum Sipuncula,* it has become apparent that the present classification requires some revision since it is inconsistent at several points. For example, the arrangement of the longitudinal muscles in Golfingia and Phascolosoma, whether they are united into a single sheet or split into a number of longitudinal strands, is a currently accepted criterion for separating these genera; yet both conditions occur in the genus Aspidosiphon as it is at present recognized. Fisher (1952: 373-375) published a revision, incomplete in several respects, which he was never able to finish; the classification now suggested in this paper is mainly a continuation of his scheme and takes into account the species which he omitted."
