664 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
plates radiately furrowed near the outer margin.” Miller says: “ 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 there 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. 
Remarks. — We do not quite understand what Miller means by “ radial 
sutures ;”’ whether he alludes to the interbasal sutures which are radially dis- 
posed, or to the iéer-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 Wuire. 
Plate LXXTI. Figs. 1, 2,3; Plate LX VIL. Fig. 6. 
1862. Wuire; Boston Journ. Nat. Hist., Vol. VIL., p. 503. 
1873. Merk and Wortuen ; Geol. Rep. Illinois, Vol. V., p. 459, Plate 3, Fig. 7. 
1881. W. and Se.; Revision, Part II., p. 72 (Proceed. Acad. Nat. Sci. Phila., p. 246). 
Almost as large as P. Halli, 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 basiradial and interradial suture lines 
depressed or broadly channeled. 
Basals 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 heavier 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- 
eavated, their upper edges straight; the ambulacral notch, if represented at 
all, very small. Costals pentagonal or trigonal in the same specimen. When 
' i= 
lg 
4 
1 
_ 
