162 PALEONTOLOGY OF OHIO. 



CRINOIDEA OF THE WAVERLY GROUP. 



&ENTJS ACTINOCUmUS. Miller. 

 AcTiNocRiNUs Daphne. 



Plate 11, fig. 11. 



Actinocrinus Daphne; 17th Rept. on the N. Y. State Cab. of Nat. Hist., p. 52, 1864. Extr. 

 published in advance, Albany, Nov. 11, 1863. 



Body broadly turbinate, of medium size ; base slightly projecting over 

 and beyond the column, with a groove just within the basal margin. 

 Basal plates of moderate height, and barely indented at the suture lines. 

 First radial plates larger than any others in the body; second radials 

 hexagonal; third radials pentagonal, hexagonal, and heptagonal (some- 

 times the upper lateral angles being simply truncated), smaller than the 

 second radials, supporting on the upper oblique edges a simple supra- 

 radial plate on each side. These latter, from the outer sloping side, give 

 • origin to a simple arm, and on the inner superior side they support a 

 ■ bifurcated plate which gives origin to two arms, making six arms to the 

 ray. One of the rays (probably the anterior one) exhibits some appear- 

 . ance of having but five arms. This would give a formula of 



6.5=29 arms. 



a 



In the interradial series the lower plate is hexagonal, supporting two in 

 the second range, above which they are not known. 



Arms long and slender, not bifurcating, composed of a double series of 

 rfihort plates. The arms in the middle of their length often become flat- 

 tened on the back, and in their upper part grooved along the junction of 

 the plates, the surfaces of which are longitudinally striated in the lower 

 part, becoming nodose abovo. 



Tentacula long and slender, composed of several joints, each of which 

 supports an ascending spine. 



■ Surface of plates marked by radiating ridges extending from the cen- 



.ter to the margins. Approaching the divisions of the ray, and in the 



supraradial series, the plates become angulated along the center in the 



direction of the ray. 



Column large, round, composed of alternating larger and smaller joints. 



