. The Crinoidea flexibilia (with an atlas of and 76 plates). Crinoidea, Fossil. 170 SMITHSONIAN INSTITUTION CHOLOCRINUS Springer Plate IX Cholocrinus Springer, Jour. Geology, XIV, 1906, pp. 515, 517.—Zittel-Eastman, Textbook Palaeontology, 2d Ed., 1913, p. 203. Forbesiocrinus, Angelin (in part), Icon. Crin. Sueciae, 1878, pi. 21, fig. 18 (not fig. 21) ; pi. 28, fig. 2 (not fig. 3)- Lithocrinus, Wachsmuth and Springer (in part), Revision Palaeocrinoidea, pt. I, 1879, p. Fig. 17. Cholocrinus Lecanocrinidae with rays above radials separated by perisome only. Crown elongate. Infrabasal
. The Crinoidea flexibilia (with an atlas of and 76 plates). Crinoidea, Fossil. 170 SMITHSONIAN INSTITUTION CHOLOCRINUS Springer Plate IX Cholocrinus Springer, Jour. Geology, XIV, 1906, pp. 515, 517.—Zittel-Eastman, Textbook Palaeontology, 2d Ed., 1913, p. 203. Forbesiocrinus, Angelin (in part), Icon. Crin. Sueciae, 1878, pi. 21, fig. 18 (not fig. 21) ; pi. 28, fig. 2 (not fig. 3)- Lithocrinus, Wachsmuth and Springer (in part), Revision Palaeocrinoidea, pt. I, 1879, p. Fig. 17. Cholocrinus Lecanocrinidae with rays above radials separated by perisome only. Crown elongate. Infrabasals erect, taking part in calyx wall. Radianal rhombic, obliquely to lower left of right posterior radial. Anal x followed by perisome. Interbrachial areas filled with integument of irregular plates passing into the tegmen. Primibrachs two to five, the first not filling distal face of radial. Arms heterotomous, divergent, not abutting over interbrachial areas; ten main rami with irregular, branching ramules. Column short, cylindrical, with terminal plate for attachment. Genotype. Forbesiocrinus obesus Angelin. Distribution. Silurian; found only in Gotland. I proposed this genus in 1906 upon Angelin's species Forbesiocrinus obesus, as figured on his plates 21 and 28, on account of the different interbrachial structures, and the presence of a radianal as indicated by figure 2 of the latter plate (which proves to be an incorrect restora- tion). On neither of these characters could it be reconciled with the typical form of Litho- crinus, under which that species was ranged by Wachsmuth and Springer in 1879. At that time I was not aware of the facts since brought out by Mr. Liljevall's beautiful preparations and drawings, which confirm the separation of the genus in a very striking manner. The family position of this form is rather difficult to determine. The calyx is that of Pycnosaccus in every particular, having wide interbrachial spaces filled only with perisome, an oblique. Ple
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