men illustrated, there are three plates, followed by two plates 

 that connect with the plates of the vault, but in other speci- 

 mens only three or four plates can be distinguished. 



The vault is convex and is covered by a few large convex 

 plates, and bears a large subcentral proboscis, which is sur- 

 rounded, near the base, by large convex plates. 



This species bears some resemblance to B. imparilis, above 

 described, but the calyx is more elongated, the vault and pro- 

 boscis are altogether different, and it has only ten arms, while 

 that species has twelve. When compared with other described 

 species the differences are equally as well defined. We may 

 here call attention to the fact, that the number of plates in 

 the azygous and regular interradial areas, in the genus Baio- 

 crinus, is of less importance than the number of ambulacral 

 openings to the vault, not only as shown by this species, but 

 as shown by many otheis, in our possession. 



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

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



BATOCRINUS INSPERATUS, n. Sp. 



Plaie I, Fig. 21, azygous view; Fig. 22, opposite azygous side. 



This species is founded upon a single specimen, that seems 

 to be perfect in all its parts, and, if abnormal, we do not know 

 from what parents it arose. The calyx and vault together 

 have a sub-elliptical outline with both ends slightly truncated. 

 Species below medium size. Calyx urn -shaped, about as high 

 as wide. Plates tumid; no radial ridges; sutures distinct; 

 surface granular. Column round and small. It has, however, 

 only four radial series. 



Basals form an elevated hexagonal cup, about twice as wide 

 as the diameter of the column, and having, the plates rounded 

 below to a hemispherical depression for the insertion of the 

 column. First primary radials wider than high and of unequal 

 size, though there are only four of them. Second primary 

 radials quadrangular, and nearly as long as wide. Third pri- 

 mary radials considerably larger than the second, three hexag- 

 onal and one heptagonal, axillary, and support on each of 

 the superior sloping sides two secondary radials,' each of which 

 bears a single arm. There are, therefore, eight arm openings 

 to the vault in this species, 



