﻿66 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vol. 47 



MEGISTOCRINUS EXPANSUS Miller and Gurley 



1894. Miller and Gurley, 111. Slate Museum of Nat. Hist., Bull. 4, p. 35, 

 pi. Ill, tigs. 18, 19, 20, 21. 



A specimen in the collection of the U. S. National Museum re- 

 sembles this species in form and general proportions. Some of the 

 lower plates of the calyx are slightly elevated at the center, three or 

 four of them sufficiently to form obscure nodes, but its correspon- 

 dence with the type in this respect could not be determined as the 

 surface of the latter is not preserved. This crinoid has lost two of its 

 arms, evidently during the life of the animal, for the openings are 

 covered by small, irregularly-shaped plates. 



Formation and locality. — Middle Traverse limestone : Collins' 

 quarry, Alpena, Mich. Hamilton: Clark county, Ind., and Louis- 

 ville, Ky. 



Cat. No. 36,014 (Rominger collection) U. S. N. M. 



MEGISTOCRINUS LATUS Hall 



1858. Hall, Geol. Rep't. Iowa, 1, pt. 11, p. 480. 



Formation and locality. — Traverse (Hamilton) : Petoskey, Mich. 

 The type locality is at New Buffalo, la., in the Middle Devonic. 

 Cat. Xo. 36,020 (Rominger collection) U. S. N. M. 



TYLOCRINUS n. gen. 



(rr/or, a knob; npivov , lily.) 



Similar to Megistocrinus in form and general structure, but differ- 

 ing from it in the presence of numerous plates in the posterior inter- 

 ray, having two plates in the radial series and four in the second 

 row. Two arms in the anterior and postero-lateral rays, and two or 

 four in the antero-lateral rays. Of these characteristics, the arrange- 

 ment of the arms and the large number of plates in the anal interray 

 should be considered most important, as the presence of seven plates 

 in the radial series may prove to be an abnormality. 



Genotype. — Tylocrinus novus n. sp. 



TYLOCRINUS NOVUS n. sp. 

 (Plate XVI, 5, 5"-) 

 Description. — Calyx very small ; base flattened ; sides convex. The 

 surface of each radial is ornamented by an elevated rim which follows 

 the outline of the plate, and includes a depression at the center. 

 Above the radials, each plate of the cup bears one (rarely two) 

 prominent nodes which do not cover the whole plate. The surface of 



