430 THE CEINOIDEA CAMERATA OF NORTH AMERICA. 



erably higher than the radials, and supports 3, 2, and 1 plate, the latter 

 restuig between tlie arm-bearing palmars. Plates of the tegmen nodose and 

 of miifonn size ; the anal tube rather stout, and composed of slightly convex 

 pieces, which at intervals are interspersed with tuberculous pieces. Column 

 decreasing in size downward, the joints long. 



Hanson and Locality. — Keokuk group ; Indian creek, Montgomery' Co., 

 Ind. 



Tffpes in the collection of Wachsmuth and Springer. 



Remarks. — This species resembles Dizygocrinus hiturUnatus Hall, from 

 which it differs in the arm formula. Specimens in which the arms all are 

 single have not as yet been discovered. 



Dizygocrinus euconUS (Meek and Woethen). 

 Plate XXXV. Figs. 7a, h. 



1863. Adinocrimis {Alloprosalloerimis) euconus — M. and W. ; Proceed. Acad. Nat. Sci. Phila., p. 164. 

 1873. Safocrinus {Alloprosalloerinm) euconus — M. aad W. ; Geol. Rep. lUinois, Vol. T., p. 368. 

 1881. Batocrims euconus — W. and Sp. ; Revision Palaeocr., Part II., p. 166. 



Syn. Batoerimis subcoiiicus — Worthen ; Geol Rep. Illinois, Vol. VIII., p. 84, Plate 13, Figs. 4 and 4o. 



In general form resembling Anojjrosallocrhius. Dorsal cup very slightly 

 convex, the sides spreading abruptly from the top of the basals to the arms. 

 Base small, projecting, circular in outline, with a shallow depression for the 

 reception of the column. Surface of plates smooth, without ridges or other 

 elevations. Suture lines indistinct. Radials hexagonal, about twice as wide 

 as high. First costals quadrangular, smaller than the second. Distichals 

 two, followed in the two antero-lateral rays by two rows of two palmars, and 

 four single arms ; while the anterior ray, which has an additional distichal at 

 each side, and no palmars, has two arms. The posterior rays have palmars 

 in the division next to the anal side and three arms, there being sixteen arms 

 to the species. Structure of the arms unknown. Interbrachials three at the 

 regular sides, and six above the anal plate, the upper row at all sides arched 

 by the arm-bearing brachials. Ventral disk regularly conical, twice as high 

 as the dorsal cup, composed of rather large, slightly convex pieces ; the pos- 

 terior oral erect, and forming: the base of the anal tube. The tube stout at 

 the base and nearly central. 



Horizon and Locality. — Warsaw limestone ; Spergen Hill, Ind., Union Co., 

 Ills., and Taylor Co., Ky. 



Tijpe in the Illinois State collection, Springfield. 



