282 Thirty-fifth Beport on the State Museum. 



This species somewhat resembles C. micropterus in the radii, but 

 differs in Tall other characters. 



Formation and locality. Chemung group at East Randolph, Cat- 

 taraugus county, N". Y. 



Crenipecten Leon. 



Crenipecten Leon, Kaja,. Pal. N. Y.,vol. v, pt. 1. Plates and Explanations : 

 PI. 9, fig. 12. Jan., 1883. 



Shell of medium size, ovate, slightly oblique ; length about one- 

 sixth less than the height ; margins regularly curved, produced 

 below, rather straight on the upper part of the posterior side. Left 

 valve moderately convex ; the greatest convexity is a little below 

 the middle. Hinge-line straight, short, nearly central ; length 

 about one-third the height of the valve. Beak. acute, erect. Um- 

 bonal region not strongly marked, subtending an acute angle. Ears 

 sub- equal, small, sulci not conspicuous ; posterior ear the larger. 

 A narrow rim, slightly elevated and free from rays, extends from 

 the posterior ear along the margin of the shell. 



Surface marked with numerous distinct, rounded or sub-angular 

 rays, and wider interspaces with smaller intermediate rays, with 

 fine concentric striae and undulations at irregular intervals. The 

 rays are stronger over the posterior half of the valve. Ligamental 

 area linear, and crenulated with narrow cartilage-pits. 



The specimen described has a length of 26 mm., height 30 mm., 

 hinge-line 10 mm. 



This species differs from all the others in its form and surface char- 

 acters. 



Formation and locality. In sandstone of the Chemung group at 

 Leon, Cattaraugus county, N. Y. 



Crenipectek Winchelli. 



Aviculopecten Winchelli, Meek. Pal. of Ohio, vol. ii.p. 296, pl.15, figs. 50, 56. 



1875. 

 drenipecten {Pecten) Winchelli (Meek), Hall. Pal. N. Y., vol. v, pt. 1. Plates 



and Explanations : PI. 9, figs. 1, 2, 4, 25-30. Jan., 1883. 



Shell larger than medium, nabelliform, equilateral, not oblique ; 



length a little greater than the height ; margins regularly rounded 



below. On the anterior side, from a point two-thirds the height of 



the valve above the base, the antero-cardinal margin extends in a 



' direct line to the beak ; the posterior side, from a point a little above 



