FOSSILS OF THE ST. LOUIS GROUP. 



ECHINODERMATA. 



GEOTS BAKYCKDOJS. 

 BAKYCROUS SPECTABILIS, M. and W. 



PI. 20, Fig. 8. 

 Baryerinus sfectabilis, MEEK and WOBTHEN, 1869. Proceed. Aead. Nat. Sci. 



BODY attaining a large size, rather deeply cup-shaped, 

 though wider than high; truncated below for the attach- 

 ment of the very large column, and with sides moderately 

 expanding upward. Base basin-shaped. Basal pieces rather 

 large, nearly twice as wide as high, pentagonal in form, 

 * with mesial angle above, deeply impressed, the impression 

 being also continued down the middle to the lower edge, 

 with a broad prominence or ridge on each of its sides, also 

 extending to the lower edge, where they each terminate in 

 a little angular projection, while the lateral margins are 

 strongly and abruptly beveled, so as to form deep, wide 

 notches at the sutures. Subradial pieces large and hex- 

 agonal, excepting one on the anal side, which is heptagonal ; 

 all very profoundly impressed at the corners, so as to form 

 strong radiating ridges, extending one to each of the sides, 

 to connect with those on the other contiguous plates ; some- 

 times these ridges terminate near the central region, in 

 sharp, pinched-up nodes. First radial pieces about twice 

 as wide as high, generally a little wider than the sub- 

 radials, pentagonal in form, with superior lateral angles 



