1^14 PALEONTOLOGY OF NEW YORK. 



imicli stronj^xT. In all those clmriicters it also difTei-s more extremely from 

 L. extenualum. 



Formation and locality. In conipaet sandstone oi' the Ujiper Chemung group, 

 alternating with some red beds, on Seely creek, Tioga county, Pa. 



Liii'TuuES.M.v i'laui's, n. sp. 



PLATE XC, FIli> SS, "1. 



Shell larger than the medium size, sub-rhoniboidal : body ovate, oblique at an 

 angle of about 40° with the hinge-line ; height two-thirds the greatest length ; 

 ante-byssal and ventral margins very oblique and continuing in nearly a 

 straight line for two-thirds the length, with a slight concavity for the bvssal 

 sinus ; posterior margin very broadly curving. 



Left valve depressed-convex below, gradually l)ecumiiig mure convex above 

 the middle, and somewhat gibbous on the umbo. Right valve unknown. 



Hinge-line straight, nearl}" ec^ual to the greatest length of the shell. 



Beak sub-anterior, inclined forward, obtuse, scarcely elevated above the 

 hinge-line. Umbonal angle acute. 



Anterior end triangular, prolonged, acute. Wing joining the body of the 

 shell at the posterior extremity ; margin symmetrically concave ; extremity 

 j)roduced and acutely angular. 



Test marked by distant, sub-etiual, laniellose elevateil stri*, with liner 

 intermediate striiB. The stronger striiie are regular on the wing and posterior 

 slope of the body, and become irregular and fasciculate on the anterior side 

 and lower half. 



Interior unknown. 



The hinge shows a narrow striated ligamental area, and, apparently, a 

 .slender lateral tooth. 



A large left valve has a length of 44 mm., bciglit ■2S nun., .lud hinge-line 

 42 mm. 



This form is more oblique, and the wing is longer ami u.nrower than in 

 L. Orodes. 



