27 



and stand out their full length from the interradial areas. 

 The cast shows only a single secondary radial but the test 

 preserves two before the arms are fairly free. 



The first regular interradial is larger than a second primary 

 radial, hexagonal, and followed by two somewhat smaller 

 plates in the second range, and by two still smaller ones in 

 the third range, that separate the first secondary radials and 

 unite with the plates of the vault. The first azygous plate is 

 in line with the first primary radials and quite as large. It is 

 followed by three plates in the second range, four in the third 

 range, and two in the fourth range, that unite with the plates 

 of the vault. 



The vault is quite evenly convex, covered with polygonal 

 plates, and bears a submarginal azygous orifice. 



There is no described species very closely resembling this 

 one and, therefore, no comparison with any of them is neces- 

 sary to distinguish it. 



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

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

 specific name is in honor of the collector. After the illustra- 

 tions were drawn from a cast, we received a specimen pre- 

 serving the plates, from F. A. Sampson, of Sedalia, but as 

 the plates are small and not ornamented the illustrations are 

 about the same as if drawn from the test itself. 



MEGISTOCRINUS INDIANENSIS, n. Sp. 



Plate II, Fig. 1, basal view; Fig. 2, summit view; Fig. 5, azygous 

 side view. Some of the sutures are obscure and are not 

 shown in the illustrations. 



Species large. We have a specimen one half larger than the 

 one illustrated. The capacity of the vault in some specimens 

 is greater than that of the calyx. Calyx broadly basin shaped, 

 slightly concave about the basal plates, from two and a half 

 to three times as wide as high, not constricted below the arms 

 but continuing to expand as far as the free arms, which are 

 directed nearly horizontally or upward at an angle of less than 

 twenty degrees. Surface ornamentation of the plates not pre- 

 served in any of our specimens. Column moderate size and 

 having a large, slightly cinque foil canal. 



Basal plates form an hexagonal disc about one-fourth wider 

 than the diameter of the column. The first primary radials 

 are unequal in size; those abutting a single basal are hexagonal, 



