238 Thirty-fifth Report on the State Museum. 



spaces. The lines of growth are fine and obscure on the specimen. 

 The ears are marked by from five to eight rays similar to those in 

 the body of the shell. In the original description of this species 

 mention is made of small, spinose processes from the concentric 

 stride ; these do not exist in this specimen, which is a partial cast of 

 the interior. The ligamental area is a linear furrow along the 

 hinge-line ; cartilage pit small, situated under the beak. 



The left valve described has a height of 17 mm., and an equal 

 length ; hinge-line 13 mm. 



This species is distinguished from A. striatus by its more circular 

 form, obtuse beak, and stronger radii. Compared with A. celsus, 

 the ears are smaller, and the height comparatively much less. 



Formation and locality. In the yellow sandstone of the Waverly 

 group at Newark, Ohio. 



AVICULOPECTEtf (OrENIPECTEN ?) INCULTUS. 



Aviculopecten (Orenipecten ?) incultus, Ha.ll, Pal. N. Y., vol. v, pt. i. Plates 

 and Explanations : PI. 9, fig. 3. Jan., 1883. 



Shell small, longitudinally very broad-elliptical, nearly circular; not 

 oblique to the hinge-line, sub-equilateral ; height somewhat less 

 than the longitudinal diameter; basal margin regularly rounded. 

 Right valve depressed-convex. Left valve unknown. Hinge-line 

 straight, central, length one-half the length of the 'shell. Beak 

 obtuse, rounded, not rising above the hinge-line; sides of the umbo 

 straight. Ears small, sub-equal, narrow-triangular, separated from 

 the sides of the umbo by sulci. Margin of posterior ear concave ; 

 extremity obtusely angular. Anterior ear defined by a deep, angular 

 byssal sinus ; margin convex ; extremity rounded. 



The external markings of the test are not preserved. The cast of the 

 interior is nearly smooth. Pallial line faintly impressed. At each 

 side of the umbo there is a shallow, undefined impression, nearly 

 parallel to the margin, extending to about the middle of the length 

 of the shell. 



A specimen of the right valve has a height of 15 mm., length 17 

 mm., hinge-line 8 mm. 



This species approaches very nearly several forms referred to 

 Crentpecteis". More perfect material may show the hinge to be cren- 

 ulate, which character would exclude it from Aviculopecten. 



Formation and locality. In conglomerate, referred to the Upper 

 Chemung group, near Olean, Cattaraugus county, N. Y. 



