56 



in the calyx, a little wider than high, three heptagonal, two 

 hexagonal. Second primary radials about half as large as the 

 first, wider than high, four hexagonal, one pentagonal. They 

 differ somewhat in size. Third primary radials smaller than 

 the second, the superior part directed nearly horizontally, 

 three pentagonal, two hexagonal, axillary, and support on each 

 upper sloping side a single secondary radial. The secondary 

 radials are short and directed horizontally, and the articulat- 

 ing facets are quite concave, and each one is marked by a 

 large ambulacral notch. There are only ten ambulacral open- 

 ings to the vault. 



There are five plates, in each regular interradial area. The 

 first one is about as large as a second primary radial, it is 

 followed by two smaller plates, in the second range, and these 

 by two plates, in the third range, that separate the secondary 

 radials and curve in upon the vault to unite with the plates 

 of the vault. There are ten plates in the azygous area. The 

 first one is in line with the first primary radials and of about 

 the same size; it is followed by two plates in the second 

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

 that curve in upon the vault to unite with the summit plates. 



The vault is unknown. 



This species is so radically different from all others that 

 have been described, that no comparison with any of them is 

 necessary. 



Found by Mr. F. A. Sampson, the well known and promi 

 nent naturalist, in the Chouteau limestone, at Sedalia, Missouri 

 and now in his collection. The specific name is in honor of 

 the collector. 



Family DOLATOCRINIDiE, 



DOLATOCRINUS NODOSUS, n. Sp. 



Plate III, Fig. 1, basal view; Fig. 2, azygous side view; Fig. 



3, summit view. 



Species above medium size. Calyx hemispherical, broadly 

 truncated below. No radial ridges. Each plate bears a prom- 

 inent conical central node, from the base of which there are 

 numerous, more or less interrupted radiating lines, and toward 

 the upper part, irregular, low, scattering nodes. Column 

 round and having a large cinque foil columnar canal. 



