62 



preserved. The tertiary radials are short, wide, quadrangular, 

 and abut against each other, in the same manner that the 

 secondary radials do. This arrangement gives to each of these 

 four rays four arms. In the ray opposite the azygous area, 

 the seoond primary radial is the largest plate in the body 

 and nearly square. It is followed by a short, quadrangular 

 plate, and then follows a short pentagonal plate, that is axil- 

 lary and supports upon each upper sloping side a long series 

 of short, wide, quadrangular, secondary radials, which gives to 

 this ray two arms. There are, therefore, eighteen compact 

 arms in this species. 



The azygous area is of moderate size and the plates are ar- 

 ranged as is usual in this genus. The first one is pentagonal 

 and rests between the sloping sides of two subradials and be- 

 low the under sloping side of the first radial, on the right. 

 The second plate is long, hexagonal, truncates a subradial and 

 reaches as high as the top of the second radial on the left. 

 The fourth plate is much smaller than the third, truncates the 

 sesond and extends a little beyond the third. The fifth plate 

 truncates the third and is not fully exposed in our specimen. 



This species is readily distinguished by its general form, and, 

 so far as known, has no nearly related species, in the group 

 of rocks, in which it occurs. 



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

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

 cific name is in honor of the collector. 



POTERIOCRINUS ALTONENSIS n. Sp. 



Plate IV, Fig. 5, azygous area on the right, calyx arms and 

 part of the column, compressed; Fig. 4, opposite 

 view of same specimen. 



Species quite small, constricted above the calyx in the mid- 

 dle of the second radials or brachials. Calyx short, hemispher- 

 ical or bowl- shaped, nearly twice as wide as high; plates con- 

 vex; sutures distinct; surface granular. Column quite small 

 and round, the alternate plates slightly projecting. 



Basals depressed and extending a little beyond the column, 

 so as to be seen from a basal view. Subradials rather wider 

 than long and forming, with the basals, a low cup. First ra- 

 dials wider than long f pentagonal, truncated the entire width 

 above and separated from the second radials or brachials by a 



