76 



striction below the articulating facet, and by the semi-elliptical 

 facet. These surface characters readily distinguish it from 

 other species. 



Found by R. A. Blair, in the Burlington Group, at Sedalia, 

 Missouri, and now in the collection of S. A. Miller. 



PLATYCRINUS CASULA, n. sp. 



Plate IV, Fig. 37, basal view; Fig. 3S, azygous side on the right; 

 Fig. 39, view opposite the azygous side; Fig. 40, summit view. 



Species medium size and belongs to the bowl-shaped forms. 

 Calyx bowl- shaped, pentagonal, rather more than one and a 

 half times as wide as high. Plates thick. Sutures broadly 

 beveled. Surface without ornamentation. Column round at 

 the calyx. 



Basal disc pentagonal, nearly three times as wide as the 

 diameter of the column and having a height about equal to 

 the thickness of a plate. It is concave below for the column 

 attachment, and bordered by an angular pentagon from which 

 it is beveled to the suture above. First radials a little wider 

 than high, slowly expand to form the cup and become convex 

 toward the facets, for the second radials. The facets are semi- 

 elliptical, directed at an angle of forty-five degrees, and occupy 

 about half the width of the plates. The second radials are 

 very short and axillary. The ambulacral notch is small in both 

 the first and second radials. The angles for the reception of 

 the interradials, which are in fact plates of the vault, are quite 

 obtuse. 



The vault is only slightly convex and is covered with a few 

 rather large convex plates. Five large plates occupy the central 

 part and these are surrounded by a single row of plates con- 

 sisting of the interradials and those covering the ambulacral 

 canals and those forming the proboscis on the azygous side. 

 The proboscis is large and consists of numerous small plates, 

 and the first azygous interradial, which is large, stands upright 

 and forms part of it. 



The species is distinguished by its pentagonal, bowl- shape, 

 absence of ornamentation and peculiar vault and proboscis. 



Found by R. A. Blair in the Burlington Group, at Sedalia, 

 Missouri, and now in the collection of S. A. Miller. 



