BATOCEINIDiE. 



409 



incurving; pinnules dosely packed. Interbracliials variable in number, 

 either arched over by the higher brachials, or in contact with the inter- 

 ambulacral pieces. Interdistichals frequently represented, and occasionally 

 interpalmars. Anal tube stout, central and extremely long. Orals excen- 

 tric ; the posterior one much larger than the others and erect, forming the 

 base of the anal tube at the anterior side. Column round, with a small 

 pentangular canal. 



Distrihution.— Restricted to the Upper Burlington limestone and Keokuk 

 group of America. 



T//pe of the genus. — EidncJwcn'mis Christyi (Shumard). 



RemarJcs. — Eutrocliocrinus approaches Diz/jgocrinus in its arm structure, 

 but differs from it essentially in other respects. In Dizygocrinus the calyx 

 is subglobose, the tegmen high, the arms rather long, the anal tube short 

 and slender. In Eutrocliocrinus the calyx is decidedly wheel-shaped, the 

 ventral disk almost flat, the arms very short, and the anal tube extremely 

 long. 



Eutroerinus Christyi (Shumakd). 



Plate XXIX. Fig. 6, and Plate XXXII. Figs, la, h, c. 



184S. Actmocrinites — Cnvii&i^'s, letters on Geology, Plate I., Figs. 1 and 3. 



1855. Actinoerinm CV/m^yi' — SnuisiAKD ; Gaol. Rep. Missouri by Swallow, Part II., p. 191, Plate A 



1873, Batoerims GArist^i — Meek and Wokthen ; Gaol. Rep. Illinois, Vol. V., Plate 5, Pigs. 4a, i. 

 1878. .Sa^OTTOS Oim^yj — W. and Sp.; Proceed. Acad. Nat. Sci.Pbila., p. 231. 

 1885. Actimcrmus CTra^yi'— Quesstedt; Handb. der Petrefactenkunde (Auflage 3), Plate 77, Fig. 4. 

 1881. .B«i;om»?<s C/imi>! — W. and Sp.; Revision Palffiocr., Part II., p. 166. 



(not Actiiiocrimis Chrisfi/i — 'Bj.VL, li&Z = Periechocriims WhitfieUi). 



Syn. Saiocrims bisbrachiatus Whitfield ; Mem. Amer. Mus. Nat. Hist , 1893 Vol I p 13 Plate 

 2, Figs. 4, 5. ' ■• i- ' 



Syn. BaUjcriims altiuscului Millek and GuiiLEY, 1S94 ; Geol. Surv. Missouri, Bull 3 p 20 Plate 5 

 Figs. 1, 3, 3. • . 1- . > 



Calyx large, wheel-shaped; plates thick and without ornamentation. 



Dorsal cup almost twice as high as the ventral disk ; sides concave, grad- 

 ually spreading to the top of the radials, and more abruptly thence to the 

 arm bases ; plates nearly flat. 



Basal cup large, somewhat wider than high, a httle thickened near the 

 lower end, and projecting laterally beyond the sides of the column; the 

 bottom deeply exca,vated. Radials quite variable in form, but generally 

 longer than wide ; the upper face concave. Costals small, both together not 

 more than half the size of the radials ; quadrangular and pentangular. Dis- 

 tichals and palmars in two rows; the latter larger than any of the other 



