314 SMITHSONIAN INSTITUTION 



EURYOCRINUS Phillips 

 Plate XL, figs. 1-8 



Euryocrinus Phillips, Geology Yorkshire, II, 1836, p. 205. — Goldfuss, Nova Actae Acad. Leop. XIX, 

 1839, P- 352.— (Euryocrinites) Austin and Austin, Ann. and Mag. Nat. Hist., (1) X, 1842, p. 109.— 

 Morris, Cat. British Fossils, 1843, p. 52 (2d Ed., 1854, p. 79).— Bronn, Lethaea Geognostica, I, 

 1856, p. 22.— Rofe, Geol. Mag., (1) X, 1873, p. 263.— Wachsmuth and Springer, Revision Palaeocri- 

 noidea, I, 1879, p. 33.— Bather, Rep. British Assoc, for 1898 [1899], p. 923; Treatise on Zoology 

 (Lankester), pt. 3, 1900, p. 190. — Springer, Jour. Geology, XIV, 1906, p. 483.— Zittel-Eastman, 

 Textbook Paleontology, 1913, p. 205. 



A 



o 



o 



Fig. 41. Euryocrinus 



Ichthyocrinidae with rays above radials partly separated by solid plates 

 arched over by brachials. Crown expanding upward from radials. Infrabasals 

 entirely within the ring of basals, sometimes resorbed. Posterior basal elongate. 

 No radianal. Anal x followed by others mostly in single series, filling the area. 

 Interbrachials few, usually limited to a single series. Primibrachs three. Arms 

 dichotomous, abutting. Column large, expanding toward the calyx. 



Genotype. Euryocrinus concavus Phillips. 



Distribution. Devonian to Lower Carboniferous; England and the United 



States. 



Considered according to the criteria which I have adopted as controlling in this group, 

 Euryocrinus stands structurally nearer to Amphicrimts than to any other genus. It has the 

 same compact anal side with mainly a single series of plates, but it lacks the disproportionate 

 and unusual development of plates in the other interbrachial areas ; and it has three primi- 

 brachs instead of two. The inequality among the basals is not so pronounced as in that genus. 

 In superficial appearance it is close to Parichthyocrinus, with which it also agrees in number 

 of primibrachs. The character of the anal interradius, entirely filled by solid plates suturally 

 joined to those of adjacent rays, differentiates Euryocrinus on grounds of family importance, 

 which are perfectly clear in normal specimens of Parichthyocrinus with its tube-like anal 

 series bordered by a pliant integument. Some variation in the structure in the latter genus 



