710 THE CEINOIDEA CAMERATA OF NORTH AMERICA. 



not taking up the full width of tli3 facets. Arms five to six, arranged as in 

 P. sioinifer, and covered by similar nodes, as also the plates of the dorsal cup. 

 Ventral disk high ; the orals large, with a highly elevated central node, 

 which at the top divides into two or three sharp processes. The interambu- 

 lacral plates flat and erect ; the middle one of the first row sharply hexan- 

 gular, and bearing a small central tubercle. 



Horizon and Locality. — Same as last. 



Types in the collection of Wachsmuth and Springer. 



Renmi-Jcs. — Most of the specimens of this species agree in the form of 

 the dorsal cup with the Discoideus group, but in the ornamentation and arm 

 structure resemble P. verrucosus, P. hemisphericus, and P. Yandelli. There 

 are other specimens, however, in all essential points agreeing with the 

 former, in which the cup is deep and oblong, for which the name P. sjnnifer, 

 var. elongatus is proposed. 



BEaALIS GrROUP. 



Calyx cup-shaped, the plates indistinctly ornamented ; the arms curving 

 outward, and very heavy throughout. 



Platycrinus regalls Hall. 

 Plate LXXIL Figs. 1, 2. 



1861. Hall; Descr. of New Spec, of Crinoids, p. 16; figured 1872, New York State Mus. of Nat. Hist., 



Plate %A, Fig. 6. 

 1881. W. and Sp. ; Revision, PartH., p. 74 (Proceed. Acad. Nat. Sci. Pliila., p. 2i8). 

 Syn. P. Oweni Meek and Worthen ; Proceed. Acad. Nat. Sci. Pbila., p. 129. 



A rather large species. Calyx broadly cup-shaped, and but slightly 

 spreading; base large, rounded below; radial facets greatly projecting. 

 Arms at first directed outward, in some specimens spreading horizontally to 

 almost one third their length, the upper ends curving inward until the tips 

 rest upon the ventral disk. Surface of the plates marked by two or three 

 undulated ridges or rows of indistinct nodes, parallel to the upper margins of 

 the plates, and similar ridges, but narrower, surround the edges, giving to 

 the sides of the plates a somewhat beveled appearance. 



Basal cup unusually large, pentagonal, its inner edges resting against the 

 lower faces of the radials, sometimes overlapping them ; the interbasal sutures 

 distinctly grooved. Radials generally a little longer than wide, slightly 

 expanding, the lower faces convex, the upper faces at the sides of the facets 



