47 



nects with the vault and contains eleven plates. The first one 

 is in line with the first primary radials though much smaller; 

 it is followed by two plates in the second range, one of which 

 is larger than it is. There are four plates in the third range 

 that gives to the area a width nearly as great as the length. 

 There are three plates, in the fourth range, that are followed 

 by a single plate in the fifth range, that connects with a singe 

 plate belonging, at least in part, to the vault. An ovarian 

 pore is at a lateral angle of the last mentioned plate, which 

 shows that it should be classed with the vault plates rather 

 than with those of the calyx. There is a single, small, inter- 

 secondary plate in the area between the two arms and the 

 three arms in each ray adjoining the azygous area. 



The vault is elevated above the ambulacral openings, convex, 

 and bears a central proboscis. It is covered by numerous 

 polygonal, convex or spinous plates. It is not concave 

 in the regular interradial areas, but is concave toward the 

 margin in the azygous area. There are fourteen ovarian aper- 

 tures, two separating the two arms from the three arms be- 

 longing to each ray adjoining the azygous area and two be- 

 tween the ambulacral openings belonging to each of the five 

 radial series. 



The specimen upon which this species is founded was col- 

 lected by R. A. Blair, at Sedalia, Missouri, and was presented 

 by him to S. A. Miller, among other fossils from the Chou- 

 teau limestone of that locality, several years ago. It has the 

 light lead color of the Chouteau fossils and that of light yel- 

 lowish color of the fossils from the Burlington Group of that 

 locality. Were it not the color of the fossil itself, we might 

 suppose that it is from the Burlington Group, and that it had 

 accidently fallen in with the Chouteau fossils. But the rock 

 js evidently the same as that in Adinocrinus (?) Choideanensis, 

 collected by Mr. F. A. Sampson and in other crinoids described 

 from the Chouteau limestone of Sedalia. It does not seem to 

 have any near affinity with any other crinoid from rocks of 

 the age of the Chouteau, nor is it near enough specifically, to 

 any described form from the Burlington Group to require any 

 comparison for the purpose of pointing out differences. We have 



