664 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 



plates radiately furrowed near the outer margin." Miller sajs : " This species 

 need not be mistaken for any other, because in P. planus, and others having 

 any resemblance to it, the angularity of the cup follows the radial sutures, 

 and thei'e are deep excavations for the insertion of the second radials 

 (costals)." 



Horizon and Locality. — Upper Burlington limestone ; Sedalia, Mo. 



Type in the collection of S. A. Miller, Cincinnati. 



RemarJcs. — We do not quite understand what Miller means by "radial 

 sutures; " whether he alludes to the interiasal sutm-es which are radially dis- 

 posed, or to the tnfer-radial sutures. The species was described by Miller 

 from an imperfect specimen in which, as shown by the figure, only the basals 

 and portions of the radials were preserved, and it is possibly identical with 

 some other Burlington species. Our description ' is made after Miller, we 

 having no specimens for comparison. 



Platycrinus incomptus White. 

 Plate LXXI. Figs. 1, 2, 3; Plate LXVII. Fig. 6. 



1862. White ; Boston Journ. Nat. Hist., Vol. VII., p. 503. 



1873. Meek and Wokthen ; Geol. Rep. Illinois, Vol, V., p. 459, Plate 3, Kg. 7. 



1881. W. and Sp.; Kevision, Part II., p. 72 (Proceed. Acad. Nat. Sci. Pliila., p. 246). 



Almost as large as P. HaUi, and in the form of the calyx often closely 

 resembling it, but differing essentially in the branching of the arms. Height 

 of dorsal cup compared with the width as four to five in large specimens, 

 and as three to four in small ones, the base of the latter being proportion- 

 ally shorter, and rather distinctly flattened ; the sides somewhat convex. 

 Plates moderately heavy, the surface smooth or indistinctly granular, their 

 edges slightly beveled, and the basi-radial and interradial suture lines 

 depressed or broadly channeled. 



Ba«als more or less truncated at the bottom ; the intervening sutures 

 frequently visible in young specimens. Radials about as long as wide, the 

 height rarely exceeding the width, a little wider near the top than at the 

 bottom ; the median portions of the plates much heavies than their mar- 

 gins; the upper faces on either side of the facets sloping and forming a 

 notch, of which the one at the anal side is wider and deeper than the others. 

 Facets semi-circular to semi-ovoid, facing obliquely upwards, very little ex- 

 cavated, their upper edges straight ; the ambulacral notch, if represented at 

 all, very small. Costals pentagonal or trigonal in the same specimen. When 



