200 CRINOIDS. 



Platycrinus burlingtonensis Owen & Shumaed. 



Plaiycrinus burlingtonensis Owen & Shumard, 1850: Jour. Acad. Nat. Sci., 

 Phila., (2), vol. II, p. 60, pi. vii, fig. 5. 



Platycrinus burlingtonensis Owen & Shumard, 1852: Geol. Sur. Iowa, Wis- 

 consin and Minnesota, p. 589, pi. vA, fig. 5. 



Platycrinus exsertus Hall, 1858: Geology Iowa, vol. I. p. 589, fig. 61. 



Platy ennus inornatus McChesaej, 1860: Oesc New Pal. FosB., p. 6. 



Platycrinus burlingtonensis McChesney, 1867: Traus. Chicago Acad. Sci., 

 vol. I, p. 9, pi. iv, fig. 3. 



Platycrinus burlingtonensis Meek & Worthen, 1873: Geol. Sur. Illinois, vol. 

 V, p. 452, pi. iii, figs. 6a-c. 



Platycrinus lautus Miller, 1891: Geol. Sur. Missouri, Bui. 4, p. 17, pi. 2, 

 figs. 3-4. 



Calyx small, subglobose, basal cup low; radials slightly 

 protuberant at the arm bases ; sutures impressed. Plates of 

 the ventral side large, nodose ; anal opening at the end of a 

 small, stout tube. 



Horizon and localities. — Lower Carboniferous, Lower Bur- 

 lington limestone: Sedalia, Hannibal. 



Platycrinus aequalis Hall. 



Platycrinus cequalis Hall, 1861 : Uesc. New Species Crinoids, p. 117. 

 Platycrinus cequalis Meek & Worthen, 1873 : Geol. Sur. Illinois, vol. V, p. 



456, pi. iii, figs. 8-8c. 

 Platycrinus hatiola Miller, 1891: Geol. Sur. Missouri, Bui. 4, p. 22, pi. iii, 



figs. 1-2. 



Calyx cup-shaped, regularly rounding below to the col- 

 umnar facet, which is elliptical in outline and very slightly pro- 

 tuberant; basal portion about one-fourth the height of the 

 dorsal cup, with sutures almost obliterated ; radials slightly 

 longer than wide, with impressed sutures. 



Horizon and localities. — Lower Carboniferous, Burlington 

 limestone : Sedalia, Louisiana. 



Platycrinus sculptus Hall. 



Platycrinus sciclptusE.M, 1858: Geol. lowa, vol. I, p. 536, pi. viii, fig. 11. 

 Platycrinus rotundus Miller, 1891: Geol. Sur. Missouri, Bui. 4, p. 20, pi. 

 ii, figs. 11-12. 



Calyx about as high as broad; regularly rounded below; 



basals occupying a little over one-third the height of the dorsal 



