272 BULLETIN 88, UNITED STATES NATIONAL MUSEUM. 



"The entire breadth of a mature individual, across between the 

 extremities of the rays on opposite sides, if these rays were straight- 

 ened out, would be about 5 to 6 inches." 



Formation and locality. This species occurs quite commonly in 

 the famous crinid bed at Crawfordsville, Indiana, in the Keokuk 

 formation of the Mississippic. Specimens are in several American 

 museums; two are at Yale University, others in the United States 

 National Museum. 



Cat. No. 59392, U.S.N.M. 



ONYCHASTER ASPER Miller. 



Onychaster asper MILLER,. Seventeenth Rep. Geol. Surv. Indiana, 1892, p. 684, 

 pi. 12, figs. 3-5; advance extras, 1891, p. 74, pi. 12, figs. 3-5. MILLER, N. 

 Amer. Geol. Pal., App. 1, 1892, p. 680, fig. 1240; App. 2, 1897, p. 749, fig*. 

 1366. KEYES, Missouri Geol. Surv., vol. 4, 1894, p. 131. 



Original description. " Dorsal side covered with an integument of 

 small plates and numerous short spines. Central disk rather large, 

 circular, convex, inflated from the point of contact with the arms. 

 The outer integument covers the whole surface of the central disk, 

 leaving no orifice exposed. Where the outer integument is worn off 

 the disk is composed of rather large, polygonal spine bearing plates. 

 The spines do not arise from the center of the plates, but laterally 

 from little pits or sockets at the sutures. These sockets give the 

 plates a somewhat sculptured appearance. The spines have a bulb 

 at the base and taper to an obtuse point above. 



"The arms are long, rounded on the dorsal side, and very flexible. 

 Figure 4 shows the arms abruptly folded from the middle over the 

 ventral part, while figures 3 and 5 have the arms folded like the claws 

 of a bird grasping some small object. There is a row of spines on each 

 side of the arm furrows. 



"This species is so different from the type that the generic reference 

 is very doubtful." 



Formation and locality. In the Keokuk formation of the Missis- 

 sippic, at Boonville, Missouri. The specimens are said to be in the 

 Miller and F. A. Sampson collections. 



ONYCHASTER BARRISI (Hall). 



Protester f barrisi HALL, Desc. N. Sp. Crinoidea, 1861, p. 18. 

 Onychaster ? barrisi MEEK and WORTHEN, Proc. Acad. Nat. Sci. Philadelphia, 

 vol. 21, 1869, p. 83; Geol. Surv. Illinois, vol. 5, 1873, p. 476, pi. 10, figs. la-Id 



Hall's original description. " A fragment of an Asterias } among the 

 Burlington fossils, presents, in the rays and in the oral plates, some 

 characters in common with Protaster; but I can discover no evidence 

 of a central disk. The fragment preserves the center of the lower 

 side and parts of four rays. All that remain of the rays are two 

 distinct ranges of plates, which, near the base, are separated by a 



