The Fossil Crinoids referred to Hypocrinus Beyrich.

Authors


Abstract

Summary.

The two specimens of Hypocrinus schueideri Beyr., described by Beyrich and Rothpletz respectively, are redescribed and refigured. The structure of the genus is shown to agree with that of the Devonian family Gasterocomidæ, but it is suggested that in this case and in that of “Lecythiocrinus” adamsi the distinctive features may have been independently acquired.

The holotype of “Hypocrinus” piriformis Rothpletz is redescribed and refigured, and proved to be no Hypocrinus. It is thought to be a highly modified descendant of the Taxocrinidæ, by way of such a genus as Cydonocrinus. The left posterior radial appears to have borne a large arm, but the other arms were more or less atrophied, and the right posterior radial has almost disappeared.

Ancillary