420 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



Horizon and Locality. — In the Keokuk group at Bono, Indiana, and at 

 Keokuk, Iowa. Also in the Warsaw limestone at Spergen Hill, Ind., and at 

 Glasgow, Barren Co., Ky., and Boonville, Mo. 



Types in the collection of Wachsmuth and Springer. 



Reinarhs. — Miller's Baiomnus spergenensis was described from a speci- 

 men of Dizygocrhius Wkiiei in which the surface markings were eliminated 

 by weathering. Specimens of this kind occur frequently at Spergen Hill, 

 while well preserved specimens are rare. 



Dizygocrinus WMtei, var. didactylus W. and Sp. 

 Plate XXXV. Figs. W, 13. 



About the same size as the typical form, but the arms considerably 

 thinner, and there are two arms to each opening when perfectly developed, 

 which, however, is rarely the case. The radials and fixed brachials are trav- 

 ersed longitudinally by a strong, angular ridge. The arms are given off 

 from a minute axillary in the usual way, and ai'e slender, long, and infolding. 



Horizon and Locality. — Uppermost part of the Keokuk group ; Hamil- 

 ton, Ills. 



Types in the collection of Wachsmuth and Springer. 



Dizygocrinus decoris (S. A. Miller). 

 Plate XXXV. Fig. 6. 



1891. Batocrhv.s decoris — S. A. Millek ; Adv. Sheets 17tli Eep. Geol. Surv. Indiana, p. 61, Plate 10, 

 Figs. 7 and 8. 



Calyx of medium size, a little wider than high. Dorsal cup low saucer- 

 shaped, less than half the height of the ventral disk. Plates of the dorsal 

 cup barely convex, their surfaces covered with numerous minute irregular 

 pustules, and the radials and costals marked by small angular ridges, which 

 from the basals pass up to the arm bases. The sutures very slightly grooved. 



Basals quite short, anchylosed, and no suture lines visible : they merely 

 consist ol a thickened circular rim, which projects slightly over the top of 

 the column. Radials and costals very short, both fully three times as wide as 

 long. The costals support 2X2 distichals, and these three rows of palmars, 

 of which the upper supports the arms, except sometimes in the anterior 

 ray, which occasionally only has two arms given off from four successive 

 distichals. All distichals and palmars are comparatively wide and very 

 short, the latter in contact laterally. Arm facets nearly equidistant, large, 



