164 CRINOIDS. 



In cleaning the type specimen of Worthen's B. coxanus, 

 the sculpturing has been so nearly obliterated that it escaped 

 the notice of the draughtsman, who represented the plates as 

 perfectly smooth. 



Gilbertsocrinus typus (Hall). 



Trematocrinus typus Hall, 1860: Geol. Iowa, vol. I, Supp., p. 73. 

 OUacrinus typus VVachsmuth &-Springer, 1878: Proc. Acad. Nat. Sci., 



Phila., p. 262. 

 Gilbertsocrinus typus Keyes, 1889 : Proc. Acad. Nat. Sci., Phila., p. 288. 



Calyx very large, globose, flattened above, and extended 

 laterally into five pairs of massive, perforated appendages. In- 

 frabasals five, small. Basals five, rather large. Radials about 

 as large as the basals. Oostals somewhat smaller. Other calyx 

 brachials nearly of equal size. Arms small, delicate, biserial; 

 pinnules small. Interradials about 12 in number, the first resting 

 on the basals. Ventral side flat, with subcentral anal opening. 

 Plates convex or spinous as in the case of the basals and radi- 

 als. Column round, small. 



Horizon and localities. — Lower Carboniferous, upper Bur- 

 lington limestone : Marion county. Also Burlington (Iowa). 



Periechocrinus? white! (Hall). 



Actinocrinv^ { Megistocrinus ) whitd flail, 1861: Desc. New Species Palae. 



Crinoids, p. 2. 

 Actinocrinus { Megistoc? inus ) whitei Hall, 1361 : Boston Jour. Nat. Hist. vol. 



VII, p. 271. 

 Megistocrinus { Saccocrinus ) whitei Meek & Worthen, 1874: Geol. Sur. 



Illinois, vol. V, p. 397, pi. vi, fig. 1. 

 Periechocrinus whitei Wachsmuth & :Springer, 1881: Proc. Acad. Nat. 



Sci., Phila., p. 307. 



Calyx large, broadly obconical, with thin, smooth plates. 

 Otherwise much like a Megistocrinus. 



Horizon and localities. — Lower Carboniferous, lower Bur- 

 lington limestone : Hannibal. 



Megistocrinus evansi ( Owen & Shumard ) . 



Plate xxii, flg. 6. 



Actinocrinus evansi Owen & Shumard, 1850: Jour. Acad. Nat. Sci., Phila. 



(2), vol. I, p. 68. 

 Megistocrinus evansi Owen & Shumard, 1852: U. S. Geol. Sur. Wisconsin 



Iowa and Minnesota, p. 594, pi. vA, figs. 3a-b. 



