FOSSILS OF THE KEOKUK GROUP. 



GEJ.TS BAEYCRiyUS, Wachs. 



X 



BAKTCRIM s MAGXEFICUS, 31. and W. 



PL 12, Fig. 2. 

 Barycrinut magnitcus. MEEK and "WoBTHBX. Proceed. Acad. Sat. ScL, Phila., 1868, p. 340. 



BODY attaining a gigantic size, cup-shaped, or widening 

 rather rapidly, with moderately convex sides from the col- 

 nmn to the top of the first radials. Base shallow, basin- 

 shaped, or about four and a-half times as wide as high, 

 with a large concave facet for the attachment of the col- 

 umn, and a large, obscurely five-lobed perforation for the 

 connection of the central cavity of the column with the 

 visceral cavity of the body. Basal pieces regularly pen- 

 tagonal. Subradial plates about five or six times as large 

 as the basal pieces, as wide as long, or slightly wider, all 

 regularly hexagonal, excepting one on the anal side, which 

 is a little shorter than the others, and truncated above for 

 the reception of the anal piece, so as to present a general 

 heptagonal outline. First radial pieces about one-third 

 wider than high, and larger (particularly wider) than the 

 subradials. each presenting a general pentagonal outline, 

 and provided with a rather shallow, outward sloping, con- 

 cave facet, occupying more than one-third its entire breadth, 

 for the reception of the succeeding radials. Second radial 

 pieces very much smaller than the first, extremely short, 

 or only about one-fourth as long in the middle as wide, and 

 becoming much thinner, or wedge-shaped, on each side. 



