CEINOIDEA OF THE WAVEELT GEOUP. 177 



SCAPHIOCRINUS SUBTOKTUOSUS. 



Plate 12, figs. 15, 16. 



ScapMocrinus subtortuoms; 17tli Eept. on the N. Y. State Cab. of Nat. Hist., p. 59, 1864. 

 Extr. published 1863. 



Body small, cyathiform. Basal plates minute ; sub-radial plates about 

 as long as wide. First radial plates nearly twice as wide as long ; sec- 

 ond and third radial plates very short, but longer on the anterior ray, 

 the third radials obtusely wedge-form above, and supporting two arms, 

 which bifurcate on the ninth and twelfth plates from their origin. No 

 other bifurcations of the arms have been determined. First anal plate 

 large, pentangular ; the others unknown. 



The plates of the body are very prominent in the middle, with strong 

 angular ridges extending to the margins, and joining those of the adja- 

 cent plates. Arm plates constricted in the middle, and longitudinally 

 sub- angular. 



In the structure of the calyx, form and character of the plates, this 

 resembles the S. tortuosus of the Burlington limestone, but in the arm 

 structure, and the existence of three radial plates in the series, it more 

 nearly resembles the S. carinatus of the same formation. 



Formation and localily: In shales of the Waverly group, at Richfield, Summit 

 county, Chio. 



Genus ZEACKINUS, Troost. 

 Zeaceinus paterntts. 



Plate 12, fig. 17. 



Zeaerinus paternm; 17th, Rept. on the N. Y. State Cab. of Nat. Hist., p. 59, 1864. 

 Extr. published 1863. 



Body small ; calyx depressed or broad cyathiform. Basal plates very 

 small, concealed within the cavity of the column attachment. Sub- 

 radials of moderate size, wider than high, their lower margins curving 

 into the basal depression. First radials as wide again as high, concave 

 on their upper margins ; second radials, in the antero-lateral and postero- 

 lateral rays, sub-equal, or a little wider than high, obtusely wedge-form 

 above, and supporting an arm on each sloping side ; each of these arms, 

 in the antero-lateral ray, bifurcates on the eighth or tenth plate above 

 its origin, and the outer branch again bifurcates, while the inner re- 



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