GASTROPODA— PLEXJROTOMARIIDM. 645 



cancellated by lines of growth, rarely smooth. Umbilicus variable. 

 Devonic. 



133. E. rugu'lata (Hall). (Fig. 879, a.) Devonic. 

 Last whorl greatly expanding ; revolving striae faint, generally 



not preserved ; band broad, concave, generally showing on all 

 volutions ; slit moderate. 



In the Agoniatite limestone horizon of the Marcellus of eastern 

 North America ; also in the Hamilton group (?) of New York. 



134. E. itys (Hall). (Fig. 879, b.) Devonic. 

 Higher spire than preceding, volutions regularly expanding, 



band narrow, partly covered by succeeding whorls ; revolving striae 

 equal to transverse or stronger, often nodose from cancellation. 



Fig. 879. Euryzone rugulata, y^2 ; E. itys, X % > ■&• lucina, X %• (Copies 



from Hall. ) 



Hamilton beds of New York, Maryland, and Virginia, and 

 representative form at Falls of the Ohio. 



135. E. (Pleurorima) lucina (Hall). (Fig. 879, c) Devonic. 

 Large ; whorls rather more compressed vertically than in pre- 

 ceding, and regularly and more rapidly enlarging ; band wide, 

 crossed by succeeding whorls except in senile individuals ; revolv- 

 ing striae equal to or fainter than transverse. 



Onondaga and Hamilton of western New York and Falls of the 



Ohio. 



XL. Spiroraphe Perner. 



Umbilicated pleurotomarioids of depressed-rounded whorls, with 

 profound suture and subquadrangular section. Band above suture 

 throughout, forming strong, convex or flat spiral. Growth lines 

 strong, often elevated, strongly reflected backwards. Spiral sculp- 

 ture absent. Ordovicic-Devonic. 



136. S. arata Hall. (Fig. 880.) Devonic. 

 Whorls depressed ; moderate spire and deep sutures ; body 



whorl ventricose toward aperture ; umbilicus not large ; surface 



