In “The North American Crinoidea Camerata”, 1897, Wachsmuth & Springer discussed at length the various modes of partitioning the base, and attempted to give a morphological, if not a physiological, interpretation of the various appearances. In reviewing this part of their work (Geol. Mag., Sept. 1898, pp. 426–428) I contented myself with giving a summary of their views, corrected only in so far as facts of structure were concerned. This summary was reprinted in the Echinoderm volume of Lankester's Treatise on Zoology (1900, pp. 122, 123), although some of the theory involved in it was not in accord with the phylogenetic hypotheses expressed or implied in the taxonomic part of that work. Mr. Herrick E. Wilson has been more critical. He has brought Wachsmuth & Springer's interpretations to the bar of logic, of fact, and of physiological theory, and has found it necessary to replace most of them by a fresh series.