6 



distal side, three secondary radials. the last of which is axillary, 

 and on the proximal side two secondary radials, the last of 

 which is axillary, and bears on the distal side two tertiary 

 radials, and on the proximal side three tertiary radials, the last 

 one being axillary, giving to this ray five arms. There are, 

 therefore, thirty- three arms in this species. The arms are com- 

 posed of a double series of interlocking plates that are deeper 

 than wide in the lower part, but commence to spread, at the 

 upper third, and become perfectly flat, in the upper part, as 

 they do in Erelmocrinus, but without the usual increase in 

 width. The plates of the arms do not seem to lengthen, but 

 instead of closing, so as to have an ambulacral furrow on the 

 inner side, they become perfectly flat on both sides, or concave 

 externally. Pinnules dense. 



There are three regular interradials in each area, one large, 

 the other two small, but of unequal length. There are seven 

 azygous interradials, the first one heptagonal, in line with the 

 first primary radials, and of about the same size. It is followed 

 by three plates, in the second range, the middle one being the 

 longer and larger one. On each side of the upper part of the 

 middle plate there is a small plate that separates it from the 

 radial series. Above the middle plate of the second range, 

 there is an elongated plate that extends an angle to the top of 

 the calyx. The vault is not exposed, but it bears a long 

 slender proboscis, the end of which is broken off at the top 

 of the specimen illustrated. 



This specie will be distinguished by its depressed calyx, and 

 thirty-three arms or seventeen ambulacral orifices, in the vault, 

 and by the flattening of the arms in the superior part. This latter 

 character, in a greater degree, possibly, has been regarded as 

 a generic character in Eretmocrinus. This species and others 

 hereinafter described show that the flattening of the arms is 

 not of generic importance. Many species of Batocrinus show 

 the tendency of the arms to expand or flatten toward the 

 superior ends. 



Found in the Keokuk Group, at Boonville, Missouri, and now 

 in the collection of S. A Miller. 



