24 



This species is distinguished by its general form and structure 

 from all others that have been described and it does not seem 

 that a comparison with any of: them will aid in distinguishing it. 



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

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



SACCOCRINUS UMBROSUS, n. sp. 



Plate II, Fig. 13, lateral view, with azygous area on the right; 

 Fig. 14, lateral view, with azygous area on the, 

 left, same specimen. 



Species large. Calyx urn-shaped below, but spreading at the 

 top, so as to resemble a Slrotocrinus, and which suggested the 

 specific name. Only part of the spreading top is preserved in 

 our specimen, but enough to show it is much wider than the 

 height of the calyx. Plates thick and tumid. Sutures deep and 

 beveled. Surface ornamentation, if any, destroyed and also the 

 plates of the vault in our specimen. 



Basals one-half wider than high, very thick, stand upright and 

 form a hexagon two and a half times wider than the diameter of 

 the column. The basals extend below the point of attachment 

 with the co'umn in the form of cuneate ends with widely gaping 

 sutures below, so that the calyx will stand on the sharp and con- 

 tracted edges of the basal plates. The calyx rapidly expands in 

 rounded outline from the basals to the second primary radials. 

 First primary radials large, of unequal size, width about one- 

 fourth greater than the height, three hexagonal, two heptagonal. 

 Second primary radials about one-third the size of the first, 

 quadrangular and nearly square. Third primary radials a little 

 larger than the second, three hexagonal, two pentagonal, axillary, 

 and support on each upper sloping side one or more secondary 

 radials, the last of which is axillary and supports tertiary radials, 

 and in some of the rays, at least, there are quaternary radials. 

 All of the rays in our specimen are injured at some point above 

 the first secondary radials, so that no single ray can be com- 

 pletely described. 



The first plate in each regular interradial area is large, and in 

 the first area on the left, as shown by figure 13, there are only 

 three plates, one following the other. In one of the other areas 

 there appears to be only two, but this appearance may be due to 

 an injury that exists above the second plate. In the azygous 

 area there are nine plates, in subovate outline, that appear to fill 

 this area, but there is a large plate above these that does not 



