32 



with this species, though they are pressed somewhat out of shape, 

 except in one particular. They have three ambulacral openings to 

 the vault, in the ray opposite the azygous area, which gives to each 

 nineteen arms. In a better state of preservation they might show 

 other differences, and may belong to another closely related species. 



Found by R. A. Blair, in the Burlington Group, near Sharon, in 

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



STEG'ANOCRINUS SHARONENS1S, n. sp. 



Plale II, fig, 10, azygous side; fig. 11. opposite view; jig. 12, vault. 



Species small. Calyx obpyramidal, rather broadly truncated, pen- 

 tagonal as seen from below or above. Plates thick, nodose, pyram- 

 idal. Column large, canal small. 



Basals form a short, hexagonal cup, deeply notched at the sutures. 

 Plates below somewhat cuneiform. First primary radials rath or 

 large, nodose, wider than long, three 1 hexagonal, two hepiagonal. 

 Second primary radials about two-thirds as large as the first, sculp- 

 tured in like manner, wider than long, hexagonal. Third primary 

 radials smaller than the second, pentagonal, axillary and support on 

 each upper sloping side a single secondary radial which is axillary, 

 and beyond which the plates are not preserved in our specimens. 

 There do not appsar to be more than ten openings to the vault, but 

 they are large and the axillary plates show twenty arms. 



The interradial areas all graduate up into the vault and over the 

 ambulacral channels so as to leave no dividing line between the vault 

 and calyx. The regular interradial areas are not uniform. The first 

 plate is followed in each area by two smaller plates in the second 

 range. In each of two areas there are two plates in the third range, 

 and in the other areas three plates, and these separate the arms and 

 unite with plates that may be regarded as vault plates. In the azygous 

 area the first plate is in line with the first primary radials and about 

 the same size. It is followed by two plates in the second range, 

 three in the third range, three in the fourth range, and three in the 

 fifth range, that separate the arms. 



The vault is only slightly convex and only moderately elevated 

 over the ambulacral canals and bears a subcentral proboscis. It is 

 covered with convex and nodose polygonal plates. 



