28 



are not disposed in ranges, but tlie plates on the sides are 

 longer and larger than those more central. The first plate is 

 in line with the first primary radials, though somewhat smaller. 

 It is followed by three plates in the second range, the middle 

 one being much the smallest. There are five i)lates in the 

 third i-ange, but the one on each side extends up two ranges 

 higher than the throe middle ones do, or there may be said to 

 be as many as ten small i)lates over the central part of this 

 area before they get as high as the two lateral plates in the 

 third range. The azygous area is very wide in the superior 

 l)ai-l, and the small plates graduate into those of the vault so 

 that no definite lino can be drawn between them. As near as 

 we can judge, however, there should be credited to the calj-.v, 

 in this area, about forty plates. The two arms in each radial 

 series are close together on each side of the azygous area, 

 while the. area is wide, somewhat bulged, and covered willi 

 small, iri'egularly disposed plates. 



The vault is unknown. The species is far reuiovcd from all 

 heretofore described. 



Found by P. A. Sampson, in whose honor we have proposed 

 the specific name, in the Chouteau limestone, at Sedalia. Mis- 

 souri, and now in his collection. 



Family POTERIOCRINID.E. 



BARYCRINUS NEGLRCTUS, n. Sp. 



J 'Idle If. F'kj. 10, nzycjous view; Fig. 11, opposite view: Fifj. 12, 

 side view. Sj>ecivien slighllij compressed. 



Species medium size. Calyx obconoidal Height nearly 

 equal to the greater diameter. Surface granular. Dee]), longi- 

 tudinal depi-essions between tlie subradials, and round, deep 

 pits at the angles between the subradials and radials. Column 

 round. 



Basals longer than wide and forming a cup more than one- 

 third the length of the calyx. Subi-adials longer than wide, 

 by reason of the longitudinal i)its, they are contracted in the 

 middle; four hexagonal and one heptagonal. First radials 

 wider than long, dtieply pitted at the inferior angles, and ti'un- 

 cat(>d about three-fourtlis of the width above for the first arm 

 plates, or second radials. from which they are separated by a 



