198 CRINOIDS. 



The calyx of this form closely resembles that of P. discoi- 

 deus. The basal disk, however, is smaller, the radials at the 

 arm bases more protuberant, and the plates are usually smooth. 



Horizon and localities. — Lower Carboniferous, Lower Bur- 

 lington limestone : Louisiana, Sedalia. 



Platycrinus preenuntius Wachsmuth & Springer. 



Platycrinus prmnuniius Wachsmuth & Springer, 1878: Proc. Acad. Nat. 



Sci., Phila., p. 249, photo, pi. ii, figs. 1-2. 

 Platycrinus suleaius Miller, 1891 : Geol. Sur. Missouri, Bui. 4, p. 16, 



pi. ii, fig. 2. , 



Calyx large, basin-shaped, composed of extremely heavy 

 plates ; basal disk deeply concave, but elevated towards the 

 margin, which is beveled ; radials wider than high, broadly 

 beveled. Surface marked by indistinct wrinkles and nodes. 

 Column large, heavy. 



Sorizon and localities. — Lower Carboniferous, Burlington 

 limestone : Sedalia. 



Platycrinus pileiformis Hall. 



Plate XXV, flg. 5. 



Platycrinus pileiformis 'B.&W, 1858: Geology Iowa, vol. I, p. 529, pi. viii, 



figs. 3a -c. 

 Platycrinus pileiformis Keyes, 1890: Proc. Acad. Nat. Sci., Phila., p. 



181, pi. ii, fig. 6. 

 Platycrinus ca7'chesium Miller, 1891: Geol. Sur. Missouri, Bui. 4, p. 23, 



pi. iii, figs, 6-7, 



Calyx similar to that of F. cequalis, but more regularly 

 rounded below, and columnar facet small and circular instead 

 of large and elliptical. 



Sorizon and localities. — Lower Carboniferous, Lower Bur- 

 lington limestone: Sedalia, Hannibal ; Kinderhook ( Illinois ). 



Platycrinus pratteni Worthen. 

 Platycrinus planus Owen & Shumard, 1850: Jour. Acad. Nat. Sci., Phila., 



(2), vol. II, p. 57, pi. vii, fig. 4b. 

 Platycrinus planus Owen & Shumard, 1852 : U. S. Geol. Sur. Wisconsin, 



Iowa and Minnesota, p. 587 (in part), pi. vA, fig. 4b. 

 Platycrinus pratteni Worthen, 1860 : Trans. St. Louis Acad. Sci., vol. I, 



p. 569. 

 Platycrinus planus Meek & Worthen, 1868: Geol. Sur. Illinois, vol. Ill, 



p. 469, pi. xvi, fig. 6. 

 Platycrinus acclivus Miller, 1891 : Geol. Sur. Missouri^ Bui. 4, p. 12, pi. i,. 



figs. 9-10. 



