384 THE CEINOIDEA CAMEEATA OF NOKTH AMERICA. 



contact with one another and with the third distichals of the anterior ray. 

 Arm bases not projecting ; the arm openings equidistant. Arms eighteen, 

 of medium length, rather stout, and gradually tapering ; composed of rather 

 long joints, ^vhich on the back are marked by a short rounded node. Pin- 

 nules long. Ventral disk constructed of irregularly arranged nodose plates ; 

 and similar plates form the walls of the anal tube, which is comparatively 

 strong and extends beyond the tips of the arms. Column tapering down- 

 ward ; the nodal joints with crenulated edges, and rather long ; the inter- 

 nodal joints quite narrow. 



Horizon and Locality. — Keokuk group ; Canton, Tnd. 



Ty2ye in the collection of W. F. E. Gurley. 



Remarks — Miller and Gurley describe this species as having four arms 

 in the anterior ray. This must be exceptional, for seven of our specimens 

 show distinctly but two arms in that ray, and eighteen to the specimen. 



Batocrinus laura (Hai,l). 

 Plate XXIX. Figs. 5a, b, c, d. 



1861. Aetinoerinus laura — Hall; Prelim. Descr. New Crinoids, p. 15. 



1881. Batocrinus laura — W. and Sp. ; Revision Pateocr., Part II., p. 167. 



1893. Batocrinus &?(/« — Whitfield ; Mem. Amer. Mus. Nat. Hist., 1893, Vol. I., p. 17, Plate 1, Pigs. 



15, 16. 

 Syn. Batocrinus sajjihus Millek and GrKLEY, 189i ; Geol. Surv. Illinois, Bull. 3, p. 23, Plate 5, 



Pigs, 7, 8, 9. 



Calyx generally higher than wide, biturbinate. Dorsal cup gradually 

 and uniformly expanding to the arm bases, its sides straight or slightly con- 

 cave ; the plates flat and smooth. Basals not projecting laterally, forming 

 a short conical cup, rounded at the lower edge. Radials a little wider than 

 long, their upper faces concave. First costals less than half the size of the 

 radials, quadrangular, once and a half as wide as long, the lower face convex. 

 The second smaller than the first, pentangular. Distichals 2X2, larger than 

 the costals ; the second larger than the first and twice as wide as long. The 

 upper supports 2x2 palmar.s, of which the second is deeply excavated, and 

 forms a horse-shoe-shaped facet for the reception of the arms. Arm openings 

 large, directed obliquely upwards ; equidistant. Arms rather stout, of moder- 

 ate length, rounded on the back. Interbrachials : 1, 2, and 1. The anal 

 plate is followed by 3, 3, and 1 plate, arched by the palmars. Ventral disk 

 lower than the dorsal cup, more or less conical; plates almost flat, except 

 the posterior oral, which is somewhat convex. Anal tube central, of 



