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PLATYCRINUS MISSOURIENSIS, H. !3p. 



Plate IV., Fig. 22, longer side view, showing ihe place for ihe 

 attachment of the column; Fig. 23, shorter side view. 



Species medium size, and the specimen upon which it is 

 founded has longer first radials upon one side than upon the 

 other, which forms an unsymmetrical calyx that may represent 

 either the normal or an abnormal growth. It is also slightly 

 compressed. Calyx somewhat bowl-shaped, broadly truncated 

 below, outer face of the first radials flattened and sutures 

 beveled, so that a transverse section will have a subpentagonal 

 outline. Plates thick. Surface granular. Column round at 

 the point of attachment, rather large and surrounded by a 

 small projecting rim on the basals. Columnar canal large. 



Basals form a pentagonal disc with a very shallow cup and 

 have a projecting angular rim around the end of the column. 

 The beveled and straight sutures between the basals and first 

 radials give the basals a marked pentagonal outline. The first 

 radials are a little larger upon one side of our specimen than 

 upon the other, the longer ones expand most, so that each is 

 only slightly wider than high. Each plate is flattened below 

 the articulating facet for the second radial. Articulating facets 

 very large, occupying from one-half to two-thirds the width of 

 each plate and having a serrated outer edge, within which 

 there is a straight tranverse ligamental furrow. Wide notch 

 for the ambulacral canal. 



This species is distinguished by its bowl shape and pentagonal 

 outline, and remarkable articulating facets for the second 

 radials. 



Collected by R. S. Blair in the Chouteau limestone near 

 Sedalia, Missouri, and presented by him to S. A. Miller. 



PLATYCRINUS PETTISENSIS, n. Sp. 



Plate IV, Fig. 24, basal view; Fig. 25, side view of same specimen. 



Species medium sized. Calyx bowl-shaped, truncated for the 

 attachment of the column and projecting at the arm bases, so 

 as to give it a pentagonal outline above. Surface smooth in 

 the four specimens examined, and sutures slightly beveled. Col- 

 umn medium size. 



Basals form a cup about twice as wide as high, pentagonal 

 at the top, and truncated for the column. First radials wider 

 —10 



