1XSERTAE SED1S ~/\.<\ T 



INSERTAE SEDIS 



The following genera, which have been referred by some authors to the 

 Flexibilia, are of doubtful systematic position, or by reason of newly-acquired 

 information can now be definitely shown not to belong to the group. It is 

 therefore thought desirable for the sake of completeness, as well as to furnish 

 a clear basis for future consideration of them by others, to indicate the present 

 state of knowledge concerning them. 



CLEIOCRINUS Billings 



Cleiocrinus Billings, Geol. Surv. Canada, Rep. Progress for 1853-56, 1857, p. 276. — Can. Organic Remains, 

 Dec. IV, 1859, p. 52, fig. 17. — Bronn, Klass. u. Ord. Thier-Reichs, II, i860, p. 232. — Shumard, Trans. 

 Acad. Sci. St. Louis, II, 1866, p. 359. — Wachsmuth and Springer, Revision Palaeocrinoidea, pt. 1, 

 1879, pp. 35, 147. — Revision Palaeocrinoidea, Pt. Ill, 1886, p. 152. — Zittel, Handbuch, Palaeontologie, 

 I, 1879, p. 357. — Chapman, Classification of Crinoids, 1882, p. 2. — Miller, N. A. Geol. and Pal., 1889, 

 p. 231.— Bather, Geol. Mag. (Dec. IV) V, July, 1898, p. 325.— Rep. Brit. Assoc, for 1*898, 1899, 

 ■p. 923. — Treatise on Zoology (Lankester), Pt. Ill, 1900, p. 191. — Geol. Mag. (Dec. V) II, May, 1905, 

 pp. 231-233.— Springer, Amer. Geologist, XXX, 1902, p. 94. — Mem. Mus. Comp. Zool. Harvard, 

 XXV, No. 2, 1905, pp. 93-114. — Geol. Surv. Canada, Mem. No. 15-P., 1911, pp. 41-44. — Wood, 

 Bull. 64, U. S. Nat. Mus., 1909, p. 100. — Zittel-Eastman, Textb. Pal. I, 1913, p. 186 (Emend.). 



Genotype. Cleiocrinus regius Billings. 



Distribution. Lower Ordovician, Chazy and Trenton, Canada and the United States. 



The structure, characters and systematic relations of this genus are fully exhibited and 

 discussed in the author's papers of 1905, and 1911, viz.: Mem. Mus. Comp. Zool. Harvard, 

 Vol. XXV, No. 2, 1905, pp. 93-114, pi. i, and Geol. Surv. Canada, Mem. No. 15-P, 1913, 

 pp. 41-44, pi. 5, figs. 7-lic, — leading to the conclusion that it is an intermediate type. 

 It has the flexible calyx and loose sutures of the Flexibilia, but its pinnulate arms and sub- 

 tegminal mouth place it in closer relation with early Camerata, such as Reteocrinus. Its 

 calycine pore-rhombs proclaim its not distant derivation from the Cystids. In the remark- 

 able disposition of the basal and radial plates, in horizontal alternation instead of vertical 

 succession, enclosing the infrabasals by their exterior surface instead of meeting their distal 

 edge, this form differs from all other known Pelmatozoa. These intermediate and peculiar 

 features accord with its very early age. 



