44 



The vault is covered with polygonal, convex plates, and bears a 

 large, subcentral proboscis. It is elevated over the ambulacral 

 openings and convex toward the proboscis, except a concave inter- 

 ambulacral depression on the azygous side. No ovarian pores dis- 

 covered. 



This species evidently has its nearest affinity with Batocrinus 

 turbinaius and Batocrinus turbinatus var. elegans, with which it 

 agrees, in the radial series. In B. turbinatus, the basal plates are 

 thick, short, and form a distinct rim projecting over the column, and 

 in the var. elegans the basal plates are squarely truncate below, 

 and indented at the sutures. In this species the basal plates form 

 an obconoidal cup entirely covered below by the end of the col- 

 umn. In the regular interradial areas, in B. turbinatus and in 

 the var, elegans, there are three ranges of interradials, the last 

 plate, in B. turbinatus, lying near the bases of the arms. In this 

 species there are only two ranges of interradials and they are cut 

 off from the arm bases by the union of the two series of tertiary 

 radials above them. In B. turbinaius and in the var. elegans, 

 there are only three plates, in the second range, in the azygous 

 area, and, in this species, there are four plates. In B. turbinatus 

 there are ten azygous plates, and the last ones separate the arm 

 bases and unite with the plates of the vault. In this species there 

 are only eight azygous plates and they are cut off from the vault 

 by the union of the quaternary plates above them. There are im- 

 portant differences in the structure of the vault and minor varia- 

 tions might be pointed out, but the general expression of the 

 species will always distinguish them; and, unless we wholly set 

 aside any importance to the structure of the regular and azygous 

 areas, intermediate forms cannot bring these forms into a single 

 species, though the arm formulas bring them to a close relation- 

 ship. 



Found in the Burlington Group, at Burlington, Iowa and now in 

 the collection of S. A. Miller. 



