38 



radials less than one-fourth as large as the first, a little wider 

 than long, quadrangular. Third primary radials about the size 

 of the second, pentagonal, axillary, and support upon each uj - 

 per sloping side a single secondary radial, which gives to the 

 species ten ambulacral openings to the vault. 



Tlie first interradial truncates a subradial in the azygous 

 area, and in three of the regular interradial areas in the other 

 interradial area two plates truncate a subradial, which makes 

 it octagonal, as above stated. The first plate in the azygous 

 area is, however, larger than the first plate in either of the 

 regular areas. In three of the regular interradial areas there 

 are two plates in the second range, and in the other area there 

 are three, and in the third range three plates in two of the 

 areas and two in each of the other two areas. The plates in 

 each of these areas graduate into the plates of the vault, so 

 there is no distinct line of separation between the plates of the 

 calyx and those of the vault. In the azygous area there are 

 three plates in the second range, the middle one of which abuts 

 upon the azygous orifice, which is placed midway between the 

 ambulacral openings at the top of the calyx, where it is sur- 

 rounded by seven plates. 



The vault is slightly convex toward the center and corres- 

 pondingly depressed in the interradial areas at the margin. It 

 is covered by numerous small, polygonal, convex plates. 



This is a very strongly marked species and it is wholly un- 

 necessary to compare it with any other, though it is very 

 clearly a Rhodocrinus. 



Found by R. A. Blair, in whose honor we have proposed the 

 specific name, in the Chouteau limestone, at Sedalia, Missouri, 

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



Family CYATHOCRINID.E. 



cyathochinus CHOUTEAUENSis, Miller and Gurley. 



Plate II, Fig. 24, view opposite the azygous area of a small 

 specimen magnified two diameters. 



[Cyathocrinus choufeauensis, Miller and Gurley, Bull. No. 7 

 of 111 St. Mus. p. 68, pi. IV, fig 16, Dec. 5, 1895.] 



We have a specimen that we suppose belongs to this species, 

 but it is only about one-fourth as large as the type, and we 



