710 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
not taking up the full width of the facets. Arms five to six, arranged as in 
P. spinifer, 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. 
Remarks. — 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. Yandel. 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. spinifer, 
var. elongatus 1s proposed. 
REGALIS GROUP. 
Calyx cup-shaped, the plates indistinctly ornamented ; the arms curving 
outward, and very heavy throughout. 
Platycrinus regalis Hatt. 
Plate LX XII. Figs. 1, 2. 
1861. Hatz; Deser. of New Spec. of Crinoids, p. 16; figured 1872, New York State Mus..of Nat. Hist., 
Plate 24, Fig. 6. 
1881. W.and Se.; Revision, Part IT., p. 74 (Proceed. Acad. Nat. Sci. Phila., p. 248). 
Syn. P. Owent Muzx and Wortuen ; Proceed. Acad. Nat. Sci. Phila., 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 
