8G PALJEONTOLOGY OF NEW YORK. 



Crenipecten micropterus. 



'I.ATK I.\, FKi. a. 



Crenipecten. m'wrupteriix. Hall. Pal. N. V., vol. v, pt. 1. Plata's ami Explanations : PI. 9, ti^. 2, 8. 



Jan.. 1883. 



SiiKLL small, loniritiiilinally iiml i)i)rK[uely sub-elliptical; length somewhat 

 great-er than the height; margins regularly roundeil, produced behind and 

 extending in nearly a direct line to the beak. 



Right valve depressed-convex. Left valve unknown. 



Hinge-line short, straight, anterior; length about one-third the height (jf 

 the valve. 



Beak low, obtuse. Umhonal region not strongly defined, subtending an 

 obtuse angle. 



Ears very stuall, nearly equal, bounded by shallow sulci. Byssal sinus 

 not (li.-^tinct. 



Surface marked by numerous low, rounded radii, with wider interspaces 

 and smaller intermediate radii ; crossed by fine concentric lines of growth, 

 which arc stronger and crowded on the ears, forming their only surface 

 marking. 



Interior unknown. LiganuMital area ob.scurely crenulate. 



The specimen described has a length of 18 mm., width Iti inin., liinge- 

 line 5 mm. 



This species resembles in form C. crenulaius, but differs in the radii, and in 

 the proportionally much shorter hinge-line. The surface markings are similar 

 to C. liratus, but it is different in its proportions of length and height. 



Formation and locality. In the shales of the Chemung group at Philipsburg, 

 Alleghany county, N. Y. 



