17 



agonal, and each supports upon the superior sloping sides the 

 tertiary radials. In the ray on the left of the azygous area there 

 are three tertiary radials in each literal series and two in each of 

 the proximal series, the second of which are axillary and bear 

 upon the superior sides quaternary radials, and thus there are six 

 arm openings to the vault in this ray. If the rays are uniform 

 in this respect there are thirty arms in this species. Three of 

 them are evidently alike in this regard, and we have no reason to 

 think the other two are different, but they are so injured in our 

 specimen that it cannot be definitely determined. 



There are two small intertertiary radials, one following the 

 other in each ray. There are eight plates in each regular in- 

 terradial area, the first one is hexagonal, larger than a second 

 primary radial, and it is followed by two plates in the second 

 series, three in the third and two in the fourth which connect 

 through a sharply depressed sunken area w r ith the plates of the 

 vault. There are eleven plates in the azygous area, the first one 

 is rather larger than a first primary radial and in line with 

 them, it is followed by two plates in the second series, three in 

 the third, three in the fourth and two in the fifth, which connect 

 in a sharply depressed area with the plates of the vault. 



The vault is covered with large polygonal plates, each one of 

 which is possessed of a remarkably large ventricose central node. 

 It is sharply depressed toward the interradial areas and bears a 

 large subcentral proboscis, which is broken off in our specimen 

 at the summit of the vault. 



This species is distinguished by its great size, the number of 

 arms, the number and position of the plates in the interradial 

 and azygous areas and the ventricose nodes on the surface. 



Found in the Keokuk Group in Tennessee, and now in the 

 collection of Wm. F. E. Gurley. 



ALLOPROSALLOCRINUS CELSUS, n. sp. 



Plate IV, Fig. 9, view opposite azygous area; Fig. 10, azygous 

 view of same ; Fig. 11, basal view of same specimen. 



This species has a vault considerably higher than its greatest 

 diameter, and most ventricose opposite the azygous side. The calyx 

 is convex, at the basals, flat over the radial areas and moderately 



