PERMIAN CRINOID FAUNA FROM TEXAS 631 
posterior radials upon the distal extremity of the posterior basal, its 
distal extremity extending beyond the radials. Radianal plate absent. 
Remarks.—The genus Cibolocrinus is especially characterized by 
the reduction of the number of underbasal plates to three, and by the 
presence of a single small anal plate. The only other genus of crinoids 
at all closely related to this one having a similar number of underbasal 
plates is Tribrachiocrinus from the upper marine series of the Permo- 
Carboniferous of New South Wales, but Czbolocrinus differs from this 
Australian form in the absence of a radianal plate. 
CIBOLOCRINUS TYPUS Ni. Sp. 
(Plate I, Figs. 20-22) 
Description —Dorsal cup basin- or low bowl-shaped, nearly hemi- 
spherical in form, the surface of all the plates smooth and the sutures 
flush with the general surface of the cup. ‘The dimensions of the 
two type specimens are: diameter of dorsal cup 25.8™™ and 22.5™™, 
height of same 1r™™ and 11™™. Underbasal plates three, forming a 
pentagonal disk three of whose sides, those opposite the sutures 
between the plates, are slightly re-entrant, in the larger of the two 
specimens whose dimensions are given above the diameter of the 
underbasal disk is ro™™, the columnar facet circular, moderately 
depressed, occupying about two-thirds of the diameter of the under- 
basal disk. Basal plates large, as wide or a little wider than high, 
all except the posterior one regularly pentagonal in general outline, 
but the anterior pair are really hexagonal although the two proximal 
faces are nearly a straight line and together are equal in length to 
the proximal faces of the other two; the posterior basal is a little 
wider than the others, heptagonal in outline, being similar to the 
two anterior ones except that its distal extremity is truncated for the 
support of the anal plate. Radial plates large, wider than high, 
pentagonal in outline. Anal plate pentagonal, resting between the 
posterior radials upon the truncate distal extremity of the posterior 
basal, it is angular distally, its distal extremity reaching beyond the 
level of the radial plates. 
Remarks.—This species has been selected as the type of the genus 
Cibolocrinus, and is established upon two examples of the dorsal 
cup. No specimen preserving the arms has been observed. The 
