LAMELLIBRANCHIATA. 417 



Test marked by numerous sub-angular radii; on the umbo, each third 

 or fourth one being stronger than the others, becoming equal and rounded 

 below. 



The specimen described has a length of about 110 mm. and a height of 

 97 mm. 



This species is distinguished by its large size, moderate convexity and the 

 alternation of the radii in the umbonal region. 



Formation and locality. In the Corniferous limestone, near Columbus, Ohio. 



Panenka multiradiata, n. sp. 



PLATE LXIX, FIG. 5; AND PLATE XtIV, FIG. 18. 



In part Cardiola raiUmui (Cokrad), Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanaticma : PI. 69, figs. 



5-11. 1883. 



Shell large, sub-circular or broadly ov.ate ; length greater than the height. 

 Pallial margin regularly rounded from the anterior to the middle of the 

 posterior end, whence it is a little more abruptly curving to the post-cardi- 

 nal extremity. Anterior end short and regularly rounded. Posterior end 

 expanded. 



Valves regularly convex below, becoming gibbous or ventricose in the 

 middle and above. 



Hinge-line short, straight. Ligamental area short and high. 



Test thin. Surface marked by numerous, closely arranged, flattened or 

 convex radii. 



The specimen described has a length of 65 mm. and a height of 57 mm. 



Formation and locality. In the limestone of the Upper Helderberg group, at 

 Clarence Hollow, Erie county, N. Y. 



Panenka ventricosa. 



PLATE LXIX, FIGS. 1, 2. 



Cardiolaf elevata. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations: PI. 69, figs. 1, 2. 1883. 

 Not Mcmntii elevata, Conrad. Proc. Acad. Nat. Sci., Phila., vol. iii, p. 23. 1846. 



Shell of medium size or larger, sub-circular ; length greater than the height. 

 Pallial margin regularly curving. Anterior end large. 



