50(j PALAEONTOLOGY OF ILLINOIS. 



GENUS PLATYCRIKETES. 

 PLATYCRINITES HEMISPHEKICUS, M. and W. 



PI. 16, Fig. 6 a, I), c. 



Platycrinus hemtiphericus, MEEK and WOKTHEN, 1865. Proceed. Acad. Nat. Sci., Phila., p. 162 : also 

 Geol. Survey of HI., Vol. 3, p. 511, PI. 20, Fig. 2 a, b. 



Locality and position. Keokuk division of the Lower Carboniferous, 

 Crawfordsville, Indiana. 



GENUS PENTKEMITES. 

 PENTREMITES WORTHENI, Hall ? 



PI. 14, Fig. 11. 

 Pentremites Wurtheni, HALL, 1858. Geol. Surv. of Iowa, p C06, PL 15, Fig. 1 



Locality and position Keokuk group; Crawfordsville, Indiana. 



PENREMITES (TROOSTOCRINUSI) WOODMANI, M. and W. 



PI. 16, Fig. 4. 



Pentremites (Troostocrinus) Woodmani, MEEK and WOKTHEN. Proceed. Acad. Nat. Sei., Phila, 1868, 

 p. 356. 



BODY attaining a large size, pyrarnidal-subovate, as seen 

 in the side view, being broad below, and produced and 

 gradually narrowing upward; strongly pentagonal as seen 

 from above and below, in consequence of the projecting 

 and actually carinated character of the radial pieces. Base 

 strong, from two and a half to three times as wide as high, 

 tribolate in general outline below, and very broadly and 

 profoundly excavated along the three sutures (the excava- 

 tions being continued out beyond the base into the lower 

 ends of three of the radial pieces) ; two of them pentagonal 

 and tricarinate, and one quadrangular and bicarinate, the 

 carinse projecting considerably below the deeply sunken 

 facet for the attachment of the column, so that when placed 

 erect on a level surface the body stands upon these carinse, 

 like a tripod upon its legs. Radial pieces long and narrow, 



