GENESSEE SLATE AND CHEMUNG GROUP. 161 



Genus PLATYCRINUS, Miller. 

 Platycrinus Bedfoedensis (n. sp.). 



Plate 13, fig. 4. 



Body of medium size, pocilliform, a little wider than high. Basal 

 plates proportionally large, regularly rounding from the edges of the col- 

 umn to their superior margins, and forming about one-third of the height 

 of the cup. First radial plates large, moderately excavated for the recep- 

 tion of the second radials. Arms, four from each ray, so far as deter- 

 mined ; simple above their origin, of moderate strength, and composed 

 of a single series of wedge-formed plates, each of which extends entirely 

 across the arm, and bears tentacula on its longer side, thus giving a 

 tentacle to every alternate plate on each side of the arm. Tentacula 

 rather strong, flexuose, and composed of rather long plates, which are 

 very distinctly grooved along their inner face. 



Surface of the plates of the body apparently smooth. Column strong, 

 somewhat pentangular in the upper part, and one example very decid- 

 edly spinose on the edge of the plates. 



The specimens of this species examined are imbedded in a ferruginous 

 shale, and the characters much obscured thereby, so that the entire 

 structure can not be fully determined, especially near the bifurcations of 

 the arms. It closely resembles P. Lodensis, of the Waverly group, in the 

 general form and structure of the arms, but is of a more robust habit, 

 and differs in that the arm plates extend entirely across the arm, instead 

 of only partially across, as in that species. 



Formation and locality : In the upper part of the Erie shale, Bedford, Ohio. Col- 

 lection of Columbia College, New York. 



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