KEVISION OF PALEOZOIC STELLEROIDEA. 61 



limestone of the Trenton, in Fayette County, Kentucky. The 

 holotypc is in the collection of the State University of Kentucky at 

 Lexington. 



HUDSONASTER INCOMPTUS (Meek). 



Plate 0, figs. 1, 2. 



"Goniaster" of Agassiz, Graham, Anthony, and James, Amcr. Journ. Sci., 



ser. 2, vol. 1, 1846, p. 441 (nomcn nudum). 

 Palxaster incomptus Meek, Amcr. Joiim. Sci., ser. 3, vol. 4, 1872, p. 275; Geol. 



Surv. Ohio, Pal., vol. 1, 1873, p. 64, pi. 4, figs. 5a, 56. 

 Palxaster simplex Miller and Dyer, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 



1878, p. 29, pi. 1, fig. 6.— Miller, N. Amer. Geol. Pal., 1889, p. 266, fig. 380. 

 Palxaster clarkei Miller, Journ. Cincinnati Soc. Nat. Hist., vol. 1, 1878, p. 102, 



pl. 3, fig. 5. 

 Palxaster darhana Miller, Journ. Cincinnati Soc. Nat. Hist., vol. 3, 1880, p. 236. 



Original description {P. incomptus). — "Small; rays rather short, or 

 only about once and a half as long as their breadth at their inner ends, 

 and rapidly tapering to their outer extremities, wliich are somewhat 

 obtusely angular. Disk equaling in breadth the length of the rays. 

 Dorsal side of the rays composed each of tiu'ee rows of pieces that are 

 wider than long, about nine in each row, and increase rather rapidly in 

 size inward to the margin of the disk, which is composed of smaller 

 pieces; afew very minutepieces apparently sometimes occurbetween the 

 rows on the dorsal side of the rays [none are apparent in our materiall. 

 Surface of the dorsal pieces a little granular, but apparently without 

 spines. Madreporiform piece rather small, a Httle oval, or almost 

 circular [or trapezoidal], nearly flat, and marked by fine, irregularly 

 interrupted, radiating striae. Ventral side unlaiown." 



Emended description. — R = 11 mm., r = 6 mm., R = 1 .8r. Width of 

 ray at base 6 mm. Another larger specimen measures: II = 16 mm., 

 r = 7 mm., R = 2.3r. Width of ray at base 8 mm. Smallest speci- 

 men: R = 4.5 mm., r = 2 mm. 



Rays short, stout, tapering rapidly, convex abactinally and longi- 

 tudinally ridged, flat actinally. Disk large, probably very convex 

 abactinally during life. 



Abactinal area of rays consisting of five columns of large, thick, 

 tumid, alternating, granulose plates. In the center of the disk there 

 is a distinct, highly convex plate around which is arranged a nearly 

 complete ring of seven smaller pieces and a comparatively large open 

 space which possibly represents an anal opening. This rmg is fol- 

 lowed by another composed of five large interradial plates between 

 each of which laterally and somewhat centrally is intercalated a 

 smaller plate radial in position. Laterally and distally to each of 

 the five large interradial plates are five large radial plates which are 

 the basal pieces of the five radial columns. Against the basal plates 

 of the medial ranges there adjoin laterally two large stellate ossicles, 



