35 



right of the azygous area there are three secondary radials in 

 the proximal series and four in the distal series. Each lateral 

 ray is constructed in the same way. In the ray on the left of 

 the azygous area, there are three secondary radials, in the 

 proximal series, and five in the distal series. In the ray op- 

 posite the azygous area there are four secondary radials in 

 each series. The last secondary radial, in each series-, is ax- 

 illary. The proximal tertiary rays do not bifurcate. They arc 

 composed of subquadrate plates, thirty of which are preserved, 

 in some of the rays, in our specimen, before they are broken 

 off. The distal tertiary rays bifurcate, in four instances, -on 

 the sixth plate and in the other six rays on the fifth plate. 

 This arrangement gives to each ray six arms, or thirty arms 

 in the species. 



In the azygous area there are five plates, the first truncates 

 ?, subradial diagonally, separates the first primary radials and 

 supports two plates above. The second truncates an angle of a 

 first primary radial, instead of a subradial, as is usual in this 

 genus. It is hexagonal, abuts the second and third primary 

 radials on the left, the third azygous plate on the right and 

 supports the fourth azygous plate. The third is smaller and 

 abuts upon the first, second and third primary radials on the 

 right. The fourth is the largest in the area and extends to 

 the third secondai'y radials. The fifth presents a triangular 

 face with the superior angle as high as the summit of the 

 first tertiary radials. 



This species is distinguished by the shape of the body, num- 

 ber of secondary radials, thirty arms, and peculiar azygous 

 area. It cannot be mistaken for any other species. 



Found by Prof. A. G. Wetherby, in the Kaskaskia Group, 

 in Pulaski county, Kentucky, and now in the collection of Wm. 

 P. E. Gurley. 



ZEACRINUS DOVERENSIS, 11. sp. 



Plate II, Fit;. 20; azygous side view; Fig. 21, opposiie view; Fig. 22, 

 basal view. The specimen is slighily compressed laterally. 



Species medium size and elongate-elliptical in outline. Calyx 

 truncated below. Surface granular. Column small, round, and 

 having a minute central canal. 



Basal plates within the calyx, the hollow conical cavity 

 being filled with the end of the column. Subradials have an 

 acute superior angle visible in a lateral view. First radials 



