16 



The third primary radials adjoining the azygous area bear on the 

 distal sloping sides two secondary radials and on the proximal 

 sloping sides one secondary radial which is axillary and bears upon 

 its superior sloping sides two tertiary radials which gives to each 

 of these rays three arms. In the two lateral rays the third pri- 

 mary radials bear upon each superior sloping side a single sec- 

 ondary radial, which is axillary and bears upon each upper sloping 

 side two tertiary radials, 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 two secondary radials, 

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

 species, sixteen arms and sixteen ambulacral openings to the vault. 



There is a single, rather large, convex plate in each regular in- 

 terradial area. In the azygous area there are four plates. The 

 first one is in line with the first primary radials, though much 

 smaller, and bears a central node. It is followed by two plates in 

 the second range and one in the third, giving to the area a sub- 

 quadrate outline. 



The vault is conoidal, covered with tumid, polygonal plates and 

 bears a subcentral proboscis. There are a few of the so-called 

 ovarian apertures but they cannot be accurately determined in our 

 specimen. 



This species is distinguished by its general form, surface orna- 

 mentation, azygous area, and sixteen arms. When compared with 

 Ralocrimis laciniosns it will be noticed that the calyx is much 

 longer and yet has one plate less in the secondary and tertiary 

 series, beside the other differences. It belongs to one of the forms 

 sometimes referred to Erelmocriniis, but we see no sufficient 

 reason for so classifying it. 



Found by Prof. A. G. Wetherby in the Keokuk Group of Ten- 

 nessee, and now in the collection of Wm. F. E. Gurley. 



BATOCRINUS ARCULA, n. Sp. 



Plate II, Fig. 3, azygous side; Fig. 4, summit view; Fig. 5, 

 basal view of same specimen. 



Species rather above medium size and having a low calyx and 

 convex vault. Calyx low, saucer-shaped and having a diameter more 

 than four times its height. Radial ranges not defined and no surface 

 ornamentation. Ambulacral openings directed horizontally. Sur- 

 face smooth or granular, our specimen being silicified, the granu- 

 lar appearance may or may not represent the surface of the plates. 



