ORINOIDS. 223 



Ichthyocrinus burlingtonensis Hall. 

 Ichthyocrinus burlingtonensis Hall, 1858 : Geology Iowa, vol. I, p. 657. 



Crown pyriform, with small basin-shaped dorsal cup. In- 

 frabasals rudimentary ; basals five, very small f first, second and 

 third orders of brachials similar and rapidly widening upwards. 

 Arms closely pressed together, infolded at the ends. 



Horizon and localities. — Lower Carboniferous, Burlington 

 limestone : Louisiana. 



Taxocrinus thiemi ( Hall), 



Plate XXX, fig. 5. 



Forbesiocrinus thiemi Hall, 1861 1 Boston Jour. Nat. Hist, vol. VII, p. 

 317. 



Much smaller than T. giddingei. 



Horizon and locality. — Lower Carboniferous, Lower Bur- 

 lington limestone : Hannibal. 



Taxocrinus giddingei (Hall). 



Forbesiocnmis giddingei Hall, 1858: Geology Iowa, vol. I, p. 633, pi. xvii, 



figs. 2, 4. 

 Taxocrinus giddingei Wachsmuth & Springer, 1879: Proc. Acad. Nat. Sci., 



Phila. (Revision, p. 48.) 

 Forbesiocrinus eleganiulus Miller, 1891: Geol. Sur. Missouri, Bui. 4, p. 



40, pi. V, figs. 14-15. 



Crown rather short and stout. Infrabasals very small, 

 almost covered by the stem. Basals five, four of which are 

 about equal in size, with sharp, superior angles, the fifth larger 

 and truncated on the upper side. Eadials rather large. Brach- 

 ials of the first order, usually three in number, sometimes four, 

 rectangular ; bifurcations usually three in number ; arm plates 

 small, quadrangular. Interradial plates variable in number; 

 resting on the truncated upper angle of the posterior is a 

 vertical row of eight or more quadrangular plates, united to 

 the rays by smaller pieces, which are rarely observable. 



Horizon and localities. — Lower Carboniferous, Keokuk 

 limestone: Boonville. 



