CRINOIDEA. OF THE WAVERLY GROUP. 173 



In the specimen figured, a single arm on the right postero- lateral ray 

 is subdivided a second time; but, as the specimen is incomplete at the 

 summit, it can not be determined whether any of the other arms bifur- 

 cate. 



Surface smooth, or finely granulose, without distinct markings. 



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

 Summit countv, Ohio. 



POTERIOCRINUS PLEIAS. 



Plate 12, fig. 8. 



Poteriocrimts pleias; 17th Rept. on the N. Y. State Cab. of Nat. Hist., p. 57, 1864. 

 Extr. published in 1863. 



A species of small or medium size. Body somewhat broadly turbinate, 

 more expanding in the upper part; basal plates short; sub-radial and 

 radial plates comparatively short. Second radials about as wide as long, 

 larger than the first radials, supporting on each upper sloping side an 

 arm. Anal plates small and numerous, extending upwards into the pro- 

 boscis. 



Arms composed of a single series of long, sub-cuneiform plates, which 

 bear tentacula on their longer side. The arm is simple to the eighth 

 plate ; above this unknown. 



Surface smooth, or finely granulose. Column sub-pentagonal, com- 

 posed of alternating thicker and thinner plates. 



This resembles P. crineus, but is more slender in form and structure, 

 and the arm joints are proportionally larger. 



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

 county, Ohio. 



POTERIOCRINUS (ScAPHIOCRINUS ?) CORYCIA. 



Plate 12, fig. 9. 



Poteriocrinus corycia ; 17th Rept. on N. Y. State Cab. of Nat. Hist., p. 57, 1864. Extr. 

 published 1863. 



A species with a small, short, and somewhat broadly turbinate body. 

 The basal plates are wider than high, pentangular. Sub-radial plates 

 proportionally large ; first radial plates once and a half as wide as high ; 

 second radial plates as high as wide, or higher than wide, on the antero- 



