178 PALAEONTOLOGY OF OHIO. 



mains simple. The bifurcations of the postero-lateral rays have not 

 been determined. 



In the anterior ray the second radial plate is truncate above, and sup- 

 ports a single arm, which divides on the fifth plate above the second 

 radial, or the seventh in the series, and again bifurcates on the tenth 

 plate in one division, and on the twelfth plate in the other, above which 

 it continues simple. Arms rounded on the back, composed of a single 

 series of very short plates, much swollen at the bifurcations. Anal plates 

 unknown. 



Surface of the plates nearly smooth, or with arching lamellose strias. 



Column small, round, composed near the body of thin, alternately 

 larger and smaller, plates. 



This species closely resembles the Z. scoparius, of the Burlington lime- 

 stone, in general features and in the bifurcation of the arms, but difiers 

 in having a more spreading calyx and a much greater proportional 

 length of arms, with thicker arm plates, and not flattened on the back, 

 as that species. The anterior ray also differs, that one having but two 

 plates between the second radial and the first bifurcation. 



Formation and locality: In shales of the Waverly sandstone group, at Richfield, 

 Summit county, Ohio. ■■ 



Zeacrinus merope. 



Plate 12, fig. 18. 



Zeacrinus merope; 17th Rept. on N. T. State Cab. of Nat. Hist., p. 60, 1864. Extr. 

 published 1863. 



Body small, very broadly turbinate, sub-pentangular above from the 

 prominence of the second radial plates. Basal plates small, triangular ; 

 sub-radial plates about equal in length and breiadth. First radials 

 nearly twice as wide as high ; second radials equal in height and width, 

 constricted in the middle and angulated longitudinally, each one of them 

 supporting a pair of arms which rise from the upper sloping sides of the 

 plate. In the antero-lateral rays the arms bifurcate on the sixth and 

 eighth plates from their base, the outer division again bifurcating on the 

 tenth plate above the first division, and the inner division continuing 

 simple throughout. In the anterior ray the second radial plate is trun- 

 cate above ; and the second plate above this, or the fourth plate in the 

 radial series, becomes a bifurcating plate, supporting two arms, which 

 bifurcate on the tenth plate above their origin. Anal plates small. 



