16 



first azygous plate is in line with the first primary radials, and 

 though longer is somewhat smaller than either of them. It is 

 followed by two large, nearly equal plates, in the second 

 range, one in the third range, and one narrow, elongated plate 

 in the fourth range that unites with the plates of the vault. 



The vault is conoidal and terminates in a large subcentral 

 proboscis, which is broken off in our specimen, as shown in 

 the illustration. The vault is covered with a few large, convex 

 plates. 



It is unnecessary to compare this species with B. adamsensis, 

 above described, and it is so different from all other Ratocrinus 

 that no comparison with any of them will show any near affinity 

 to it. It is a well marked and peculiar species. 



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

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



BATOCRINUS MODULUS, 11. Sp. 



Plate I, Fig. 39, basal view; Fig. 40, azygous side; Fig. 41, 



summit view. 



Species small. Calyx broadly rounded below, hemispherical, 

 nearly two and a half times as wide as high. No radial ridges 

 or convex plates. Arm openings directed upward at an angle 

 of ten or twenty degrees. Surface granular. 



Basals substantially covered by the end of the column, and 

 bear a moderately concave depression for the attachment of 

 the column, which is also supported by a little rim around the 

 outside of the concavity. First primary radials nearly as long 

 as wide, three hexagonal, two heptagonal. Second primary 

 radials quadrangular, three or four times as wide as long 

 Third primary radials about one-half larger than the second, 

 pentagonal, axillary, and in the ray opposite the azygous area 

 bears upon each upper sloping side two secondary radials, 

 which gives to this ray two arms. In one of the lateral rays 

 the third primary radial supports upon each superior lateral 

 side a single secondary radial which is axillary and supports 

 on each upper sloping side a single tertiary radial, which gives 

 to this ray four arms. In each ray adjoining the azygous 

 area the third primary radial bears upon the distal side two 

 secondary radials and on the proximal side one secondary ra- 

 dial which is axillary and bears upon each superior sloping 

 side a single tertiary radial, which gives to each of these rays 



