416 PALAEONTOLOGY OF NEW YORK. 



PAN EN K A, Barrande. 1881. 

 Panenka dichotoma. 



PLATE LXX, FIG. 21 ; AND I'LATE XCIV, FIG. 13. 

 Cardiolaf dichotoma, Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 70, fig. 21. 1883. 



Shell large, obliquely ovate ; length a little greater than the height. Pallial 

 margin curving very regularly from the anterior to the post-inferior extrem- 

 ity and then more abruptly returning to the hinge-line. Anterior end short ; 

 posterior end more extended. 



Valves of moderate convexity in the lower portion, becoming gibbous in 

 the middle and above. 



Hinge-line short and straight. 



Beaks prominent, strongly incurved, turning distinctly forward. 



Surface marked by numerous prominent, radiating plications, which fre- 

 quently bifurcate. Interior unknown. 



Two specimens measure respectively 65 and 70 mm. in length, and 65 

 and 67 mm. in height. 



This species bears considerable resemblance to P. robusta of the Portage 

 group, and was formerly recognized as the same, but the beaks ai"e more prom- 

 inent than in that species, the radii are more closely arranged and frequently 

 bifurcating, while in that one they are essentially simple. 



Formation and localities. In the Schoharie grit in Albany and Schoharie 

 counties, N. Y. 



Panenka alternata, n. sp. 



Shell very large, broadly ovate; length a little greater than the height. 

 Anterior end short. 



Valves moderately convex, becoming gibbous in the umbonal region. 



Hinge-line short. Ligamental area narrow, visible beneath and posterior 

 to the beak. 



Beaks strong, incurved, turning slightly forward. 



