22 LAHVIFORM CBINOIDS 



The articular facets are well developed and strong, consisting of the 

 prominent transverse ridge behind which lies the concave depression contain- 

 ing the opening of the central canal. 



The orals rise strongly above but do not overhang the radials. Their 

 upper surfaces are shallowly concave and the posterior one bears a small 

 pustule marking the position of the madrepore. 



The surface' of the calyx and particularly that of the radials is very 

 rough and uneven and bears numerous small, irregular, closely set spinelike 

 processes. The depressions between them are filled with a brownish argilla- 

 ceous matrix so that it is impossible to determine whether or not the plates 

 are porous. The surface however strongly suggests that they were composed 

 of a comparatively coarse spirillar intergrowth which was not completely 

 transformed into solid plates. 



Remarks. — It is unnecessary to compare this species with any other as 

 its rough and irregular surface is entirely distinctive. 



Occurrence. — The holotype was obtained from shale occurring just below 

 the Piasa limestone near the center of the NE. *4 sec. 25, T. 8 N., R. 10 \\\. 

 Jersey County, Illinois. 



Kallimorphocrinus infacetus J. M. YYeller. n. sp. 

 Plate II, figs. 4a-b 



Description. — The height of the holotype i^ 1.37 mm., which is only 

 slightly greater than the greatest width, and the diameter of the basal stem 

 facet is about one-half the greatest width. The radials make up about seven- 

 tenths, the basal disc one-tenth, and the oral crown one-fifth of the total 

 height. The outline as viewed from above is roughly pentagonal but the 

 symmetry is interrupted by the irregular development of the arm facets. 



The basal disc is low and broad and slopes slightly upward and outward 

 from its large stem facet. Its upper edge is beveled for the reception of the 

 radials. 



The height of the radials is a little less than twice their mean width and 

 they are considerably wider above than below. The angular median keel 

 begins at the lower extremity of the radial and becomes more pronounced 

 upward until it ends in the articular facet. The sloping sides of adjoining 

 radials meet at the suture and form the slightly concave or nearly flat sides 

 of the calyx. The upper corners of the radials are slightly beveled, produc- 

 ing shallow concave notches between the arm facets. 



The articular processes of the radials are rather unequally developed. 

 They are in general large and well formed and show the same features noted 

 in A", pocillus. On the holotype, however, no articular process is present on 

 the anterior radial which perhaps was not arm-bearing, but it is also possible 

 that the structure has been obliterated by wear. In anv case this rav is the 



