58 PALEONTOLOGY OF NEW YORK. 



SiirfiR'L' oniaiiK'nkHl by numerous strong, distant, elevated, rounded ra^s, 

 with interspaces marked by a strong ray in the centre, and several finer 

 ones on each side, producing two series of alternations. Concentric striae 

 obscure. The arrangement of the rays gives the surface a fasciculate aspect, 

 especially marked in the impression of the exterior. The rays on the pos- 

 terior ear are sharp and simiilc, wliile on the anterior ear they are similar to 

 those on the body of the shell. 



Interior not observed. 



The specimen has a length of 48 iinn.. height 35 mm., hinge-line about 

 36 mm. 



This species is distinguished from P. suborbicularis by its greater length ami 

 doubly alternating radii. Though somewhat similar in form to P. crenicostatus, 

 the surface characters are very different. 



Formation and locality. In Coruiferous limestone at Stafford, Genesee county, 

 N. Y. 



Pterinopecten reflexus, n. sp. 



IT.ATK f-XXXII, FIG. 8. 



Shell of medium size, rhomboidal, moderately oblique ; length one-sixth 

 greater tliau the height; outline regularly curved to the postero-basal mar- 

 gin, thence extending posteriorly. 



Left valve depressed-convex ; mai'gin reflexed. Right valve unknown. 



Hinge-line straight, extended posteriorly, exceeding the greatest length of 

 the shell. 



Beak obtuse, low, rounded, diiected forward. Umbonal region convex, 

 sul)tending an obtuse angle. 



Posterior ear large, flat, triaugular, scarcely defined from the umlu); mar- 

 gin slightly convex ; extremity obtuse. Anterior ear small, triangular, con- 

 vex, limited by an undefined sulcus and a shallow byssal sinus; margin 

 nearly straight ; extremity obtuse. 



Test marked by fine, rounded striae, alternating with finer lines ; inter- 

 mediate spaces flat. The same surface marking continues in a subdued 



