FOSSILS OF THE IJUfLlNGTOX GROUP. 



SUBGEXUS SCAPHIOCKIXUS, Hall. 

 DBLICATUS, M. and W. 



PL 1, Fig. 5. 

 Sfaj'hwcriiius delicattu, MEEK and "WoRTHKX. Proceed. Acad. Xat. Sci., Phila., 1869, p. 144. 



BODY very small, somewhat cup-shaped, once and a-half 

 as wide as the hight to the top of the first radials ; sides 

 expanding rapidly upward from about the middle of the 

 subradials to the top of the first radial pieces, and rounding 

 under to the column below. Base very small, and nearly 

 hidden by the column, pentagonal in general outline. Basal 

 pieces merely appearing as minute trigonal facets around 

 the top of the column, and curving upward a little at the 

 extremity. Subradial pieces of comparatively rather large 

 si/e, three or four of them hexagonal (counting a very 

 obtuse angle at the middle of the under side), and one or 

 two heptagonal. First radial pieces of about the size of 

 the subradials, but shorter and wider, and all pentagonal 

 in form ; facet of each for the reception of the second 

 radials not occupying the entire breadth above, and sloping 

 outward. Second radials full twice as long as wide, measur- 

 ing the breadth at the widest part of the lower end ; slender 

 and rounded in the middle, and enlarged at the ends, par- 

 ticularly below ; each supporting two arms on their upper 

 sloping sides. 



Anal plates arranged in a double alternating series, ex- 

 actly as in the last described species. Arms slender, 

 rounded, and composed of joints, the lower of which are 

 about twice as long as wide, but those above gradually 

 growing shorter, until they become scarcely longer than 

 wide, on the longer side ; and owing to their oblique ar- 

 rangement and projections for the support of the pinnule, 

 presenting a /ig/ag appearance. At least one of the pos- 

 terior arms seen to bifurcate on the seventh piece. Pinnule 



