47 



aijoual, ami cacli sujiports upon tlic supci-ior slopiiij;- sides llu> 

 tertiary radials. In the ray on the left of the azyi>-ons area there 

 are three tertiary radials in each literal series antl 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 hav(> no reason t<i 

 think the other two are different, l)ut they are so injured in our 

 specii.ijen that it cannot be definitely determined. 



There are two small intertertiary radials, one folk)wiug the 

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

 terradial area, the first cue 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 sharijly depressed sunken area with the plates of the 

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

 is rather larger than a first primary radial aud 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, whicii connect 

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



The vault is covered with large i)()lyg(jnal 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 niimber of 

 arms, the number aud 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. 



ALL0PR0S.\LLOCKINUS CELSUS, U. sp. 



I'liitr II'. Fig. 9, rleir oppusife (i.zy^oiis tiri'ci: Fi^. If). a'.iiiJDii.f 

 ririr of same ; Fig. I], hnsal view of same s/jeci nivii . 



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 ai-eas and moderately 



