. The Crinoidea flexibilia (with an atlas of and 76 plates). Crinoidea, Fossil. TAXOCRINIDAE 345 PROTAXOCRINUS Springer Plates XLV, XLVI Protaxocrinus Springer, Jour. Geol., XIV, 1906, pp. 515, 519.—Zittel-Eastman, Textbook Paleontology, 1913, p. 205. Lecanocrinus, Billings (not Hall), Geol. Surv. Canada (Can. Organ. Remains), Decade IV, 1859, p. 46. Taxocrinus, Angelm (in part), Icon. Crin. Sueciae, 1878, p. 8. Taxocrinus (Gnorimocrinus) Wachsmuth and Springer (in part), Revision Paleocrinoidea, pt. 1, 1879, p. \MS^Qmi o 0 pi % §^ Fig. 46. Protaxocrinus Taxocrinidae with rays usua
. The Crinoidea flexibilia (with an atlas of and 76 plates). Crinoidea, Fossil. TAXOCRINIDAE 345 PROTAXOCRINUS Springer Plates XLV, XLVI Protaxocrinus Springer, Jour. Geol., XIV, 1906, pp. 515, 519.—Zittel-Eastman, Textbook Paleontology, 1913, p. 205. Lecanocrinus, Billings (not Hall), Geol. Surv. Canada (Can. Organ. Remains), Decade IV, 1859, p. 46. Taxocrinus, Angelm (in part), Icon. Crin. Sueciae, 1878, p. 8. Taxocrinus (Gnorimocrinus) Wachsmuth and Springer (in part), Revision Paleocrinoidea, pt. 1, 1879, p. \MS^Qmi o 0 pi % §^ Fig. 46. Protaxocrinus Taxocrinidae with rays usually not abutting over interbrachials. Crown elongate. Infrabasals low, taking small part in calyx wall. Posterior basal elongate. Radianal in primitive position as infer-radial directly under right- posterior radial. Anal tube-plates tending to sutural connection with right pos- terior ray. Interbrachials few, or wanting; lower part of interbrachial areas occupied by plates, or perisome, sometimes not appearing externally. Primi- brachs two. Arms dichotomous, divergent. Column slightly enlarging next to calyx. Genotype. Taxocrinus ovalis Angelin. Distribution. Ordovician, Silurian and Devonian; Gotland, the United States, and Canada. This genus includes the earliest known forms of the Crinoidea Flexibilia. It was pro- posed by me in 1906 to receive those species with the most primitive anal structure—that is, the radianal in form of a radial at the base of the right posterior ray; among them are several of Angelin's Taxocrini which Wachsmuth and Springer had separated under Gnorimocrinus. At that time I was not fully aware of the structure of Billings's species Lecanocrinus elegans and L. laevis, which are now seen to belong here and which carry the genus back to the early Ordovician. Here we have in these two species, when compared with the Inadunate genus Cupulocrinus from the same horizon and locality, a fairly close approach to the point of divergence of the Flexibilia
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