LAMELLIBRANCHIATA. 489 



PaljEanatina solenoides, n. sp. 



PLATE LXXIX, FIGS. 38, 3a. 

 In part PaUBaTiatina typa. Hall. Pal. N. Y., vol. v, pt. 1. Plates and Explanations : PI. 79, fig-s. 26-39. 



Shell elongate, sub-quadrate ; ventral and dorsal margins sub-parallel ; length 

 two and one-half times the height ; basal margin nearly straight or a little 

 contracted anterior to the middle. Posterior extremity almost vertically 

 truncate. Cardinal line straight. Anterior end short, the upper side 

 extended in continuation with the cardinal line, and curving below. 



Left valve regularly convex, scarcely gibbous in the umbonal region. 

 Right valve depressed-convex throughout. 



Beaks at about the anterior fourth, that of the left valve rising a])ove the 

 hinge-line and incurved ; in the right valve scarcely rising above the cardi- 

 nal line. In the left valve there is a flattening of the beak, and a broad 

 undefined depression below, extending to the basal margin. Umbonal slope 

 of the left valve obtusely sub-angular for a short distance from the beak, 

 merging into the general convexity before reaching the middle of the shell. 

 In the right valve the umbonal ridge is obsolete. Cardinal slope not dis- 

 tinct from the general convexity. 



Surface marked by fine concentric striae, which become fasciculate on the 

 posterior slope, and are nearly vertical to the hinge-line. 



The ligamental area is comparatively short, about one-fourth the length of 

 the shell. 



The specimen described has a length of about 42 mm. and a height of 17 

 mm. 



This shell is more elongate than the preceding, the cardinal margin is more 

 extended and straighter, the posterior end truncate ; the umbonal ridge is less 

 defined, and there is no evidence of a fold upon the post-cardinal slope. 



Formation and locality. In a conglomerate of the Chemung group, near Port- 

 ville, Alleghany county, N. Y. 



