174 PAL.ii]qNTOLOGY OF OHIO. 



lateral and postero-lateral rays; supporting on their upper eloping sides 

 arms whicli Lifurcate on the tenth plate above, with probably a second 

 bifurcation above this one. The second radial of the anterior ray is 

 twice as long as wide, truncate above, and supporting a single arm, 

 which bifurcates on the fourth plate above, giving six plates in the ray 

 below the bifurcation. Anal plates unknown. 

 Surface somewhat strongly granulose. 



This species bears considerable general resemblance to P. cauliculus, of 

 the Burlington limestone, but differs essentially in the structure of the 

 arms. 



Formation and locality : In shales of the Waverly group, Richfield, Summit county, 

 Ohio. 



Sub genus SCAPIIIOCRINUS. 



SCAPHIOCRINUS (POTERIOCRINUS) ^GINA. 



Plate 12, figs. 11, 12. 



Sca'phiocrinvs {Poteriocrinus) a-gina ; 17th Rept. on the N. Y. State Cab. of Nat Hist., 

 p. 57, 186-1. Extr. published 1863. 



Body short, turbinate, or sub-hemispheric. Basal plates very short, 

 triangular. Sab-radials about as wide as long, a little smaller than the 

 first radial plates. Radial series consisting of three plates ; the first one 

 large, wider than high, and a little projecting at the upper margin; 

 second one short and wide, quadrangular, somewhat constricted in the 

 middle. The third radials are obtusely wedge-form above and strongly 

 constricted in the middle, and supporting a single arm on each upper 

 sloping side. Plates of anal area large in the lower part, and gradually 

 decreasing above. 



Arms simple throughout, composed of elongate, sub-cylindrical joints, 

 which give origin to strong jointed tentacula from near the upper mar- 

 gin of their longer sides. These arm plates are enlarged at the origin of 

 the tentacula, Avhich are alternate on the opposite sides of the arm, giv- 

 ing it a tortuous direction. 



Column proportionally strong, sub-pentagonal, composed of alternating 

 long and short joints, with still longer ones at irisegular intervals ; the 

 longer joints are wider and sub-nodose on the periphery. 



Surface of plates granulose; those of the body slightly convex. 



In general appearance this species resembles Poteriocrinus dijfusus, of 

 the Hamilton group, to which it is also closely related, but differs in 



