Chitin in pogonophora

Abstract

POGONOPHORA secrete and inhabit tough, horny tubes. Recently, Hyman 1 quoted unpublished results indicating that the tubes of Pogonophora were composed of cellulose. In view of the presumed phylogenetic relationship of Pogonophora with lower chordates this might have been expected, since the tunicate test is rich in cellulose (tunicin). However, on examining three species of Siboglinum (S. atlanticum Southward and Southward, S. inermis Southward and Southward2, and S. caulleryi Ivanov) kindly given to us by Dr. A. J. Southward, we found the tubes to be lacking cellulose, but rich in chitin. Later, through the kindness of Academician Ivanov, we were given specimens of the tubes of Zenkevitchiana longissima Ivanov3, and the same conclusion about their composition was reached. © 1958 Nature Publishing Group.