52 



side, two secondary radials, the last being axillary, and supporting, 

 on each upper side, two tertiary radials, except adjoining the azy- 

 gous area there are three, which gives to each of these rays four 

 arms. In the ray opposite the azygous area, the third primary 

 radial bears upon each upper sloping side three secondary radials, 

 which gives to this ray two arms. There are, therefore, eighteen 

 arms in this species. The arm formula is 4+4+2+4-f4. 



In each regular inttrradial area there are three plates, one wide, 

 short plate, followed by two in the second range. In the azygous 

 area there are seven plates. The first one is in line with the first 

 primary radials and about the same size. It is followed by three 

 plates, the middle one being short and very wide; above these 

 upon the right there are three small plates, in the third range. 

 The azygous and interradial areas are widely separated from the 

 plates of the vault. 



The vault is convex and covered with large, polygonal, tumid 

 plates. It bears a subcentral proboscis. 



This species is so readily distinguished by its general form and 

 surface characters from all other eighteen-armed species that no 

 comparison is necessary with any of them. 



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

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



BATOCRINUS RUDIS, n. sp. 



Plate 1 V, Fig. 4, azygous side view. 



Species large, biturbinate. Calyx about one-half wider than 

 high, most rapidly spreading in the superior part, so as to leave 

 the sides arcuate or apparently broadly constricted from the basals 

 to the free arms. Ambulacral openings directed horizontally and 

 not visible in a basal or summit view. Plates tumid and nodose. 

 No radial ridges. 



Basals the largest plates in the body, flattened on the outside 

 and extended in expanding wedge-shaped ends below the end of 

 the column. They form an hexagonal cup, about twice as wide 

 as the diameter of the column, with widely gaping sutures below, 

 so that the calyx will stand on the cuneiform edges of the basal 

 plates. First primary radials wider than long, three hexagonal, 

 two heptagonal, and each one bears a transverse central node- 

 Second primary radials quadrangular about one-half or less than 

 one-half wider than long and each one bears a central node. 

 Third primary radials of unequal size, the one on the right of 

 the azygous area is large and heptagonal, the one on the left 



