334 EIGHTEENTH REPORT ON THE STATE CABINET. 



species has spines from the posterior borders of the cheeks, as in the allied 

 European species. 



Formation and locality. The original specimen is marked as from 

 Bridgeport, near Chicago. 



GENUS LICHAS (Dalman). 



LICHAS BREVICEPS ? 



Lichas breviceps : Hall, Transactions Albany Institute, Vol. y. 



A fragment of limestone from Bridgeport, Illinois, contains a part of 

 the head and the pygidium of a species of this genus. The glabella and 

 portions of the head remaining resemble L. breviceps, but the pygidium is 

 very different. 



LICHAS (sp.). 



The pygidium of a species of this genus in limestone from Grafton, 111., 

 has a strong rounded axis, with four rings besides the terminal one. The 

 lateral lobes are somewhat convex, but the extremities are broken off, so 

 that its entire form cannot be determined. 



GENUS SPH^REXOCHUS (Beyrich). 



SPHiEREXOCHUS MIRUS (Betrich). 



Among numerous specimens in the collection, principally of the head of 

 a species of this genus, I am unable to find any specific differences between 

 it and the European species named. 



It is widely distributed, occurring at Milwaukee, Racine, Waukesha, 

 and Greenfield, Wisconsin, and at Bridgeport, Illinois. 



GENUS CALYMENE (Brongniart). 



CALYMENE NIAGARENSIS. 



Caltmene blumenbachii, var. niagarensis. 



This species occurs in nearly all the localities of the Niagara group in 

 Wisconsin. Its most common condition is that of impressions of the exte- 

 rior crust, while casts of the interior are less frequently obtained. 



GENUS ENCRINURUS (Emmerich). 



ENCRINURUS (sp.). 



A species of this genus has been recognized in the pygidia of several 

 individuals among the collections from Racine. The specimens are not in 

 a condition to be distingushcd from the species of the Clinton and Niagara 

 groups of New- York. 



