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Show 1002 MR. F. A. BATHER ON UINTACRINUS. [Dec. 17, the stems l. Which view be ultimately accepted must depend on the evidence of intermediate stages actually found fossil, stages that shall bear the same relation to Uintacrinus as Thiolliericrinus bears to Antedon. It is true that such links are still to seek ; but tbe number of missing links is far fewer on this hypothesis than on any other that has hitherto been advanced. 4. SUMMARY. This paper attempts a complete morphological description of Uintacrinus socialis, aud a comparison of it with U. westfalicus. The deficiencies of previous accounts are made good, and the errors of them corrected : this is specially the case with regard to the interbrachials, interpinnulars, brachials, pinnules, and joints. The more accurate knowledge thus obtained enables a comparison with other crinoids to be based on something more than external appearances. It is thus shown that Uintacrinus cannot be related either to the Camerata, e. g. to Rhodocrinus as Jaekel has supposed, or to the Ichthyocrinidas as maintained by Von Zittel, Neumayr, and others. It must therefore be related either to the Palaeozoic Inadunata or to their Mesozoic descendants, the Canaliculata ( = Articulata of Miiller). Among these, a process of comparison and elimination leaves behind only the ascending evolutionary line that contains Encrinus, Dadocrinus, Pentacrinus, and Apiocrinus; and a simple inspection then enables us to fix on Dadocrinus as the one among all known genera that is the most nearly related to tbe ancestor of Uintacrinus. Whether this conclusion be right or wrong, I should like to point out that it was not present to m y mind when this investigation was begun, and that it has been arrived at solely by observation of a large number of facts and by simple induction from those facts. The circumstance that this conclusion differs from those of more eminent writers arises partly from the revision and increase of the facts concerning Uintacrinus itself, partly from the broader principles that a more accurate knowledge of the Crinoidea now enables us to apply. Knowdedge cannot be too accurate or too detailed. It is not till the details have been accumulated that we can understand their meaning. 1 Cf. D. C. Danielssen, " Crinoida," Norske Nordhavs-Exped. xxi., Zoologi, pp. 11-14 (1893); also Editorial on " Autotomy in Echinoderms," Natural Science, vol. v. p. 4 (July 1894). |