324 EIGHTEENTH REPORT ON THE STATE CABINET. 



GENUS CYATHOCRINUS (Miller). 

 CYATHOCRINUS PUSILLUS. 



Cyathocrinus pusillus : Hall, Transactions Albany Institute, Vol. v. 1863. 

 Compa,Ye Poteriocrinus pisiformis : Roemer, Die Silur. Fauna des "Westlichen Ten- 

 nessee, pa. 54, pl.iv, f. 7. 



Specimens of a small species of Cyathocrinus or Poteriocrinus, resem- 

 ble the one described by Roemer, presenting characters somewhat inter- 

 mediate between that species and C. pusillus. 



Formation and locality. In limestone of the age of the Niagara group 

 at Racine, Wisconsin. 



CYATHOCRINUS CORA (n. s.). 



Body rotund, somewhat broadly turbinate, rounded below, and gently con- 

 tracted a little below the middle of the subradial plates and swelling 

 out above ; having the upper margins of the radial plates incurved and 

 prominent in the middle. There is a single small anal plate. 



The basal plates are comparatively large, rising above the curve of the 

 base to nearly one-third the height of the cup. The subradial plates form 

 nearly one-half the height. 



The column is large and round. Arms unknown. 



The surface of the plates in the casts is marked by strong radiating striae. 

 Formation and locality. In limestone of the age of the Niagara group 



at Racine, Wisconsin. 



CYATHOCRINUS WAUKOMA (n. s.). 



Calyx rotund below, subhemispheric ; the sides above the middle of the 

 subradial plates nearly straight or but little spreading. Basal plates 

 small ; subradial plates large, curving upward for about half their 

 length ; radial plates about as large as the subradial. 



The subradial plates have been marked by a central node, from which 

 radiate strong ridges to the margins, joining similar ridges on the 

 adjacent plates. Two of these from the lower sides of each of the radial 

 plates converging to near the centre of that plate, and uniting, extend in 

 a single ridge to the upper margin. The surface markings beyond the 

 strong ridges are unknown. 

 This species is of different form : with more elevated sides and different 



surface markings from C. pusillus, which occurs in the same formation. 

 Formation and locality. In limestone of the Niagara group at Racine 



and Waukesha, Wisconsin. 



20 



