LAMELLIBRANCHIA TA. 
439 
Lunulicardium transversum, n. sp. 
PLATE XCIV, FIGS. 24, 25. 
Shell above the medium size, sub-cylindrical; length more than twice the 
height; basal margin gently curving. Posterior extremity narrowly 
rounded. Cardinal line essentially straight, declining posteriorly. Hiatus 
elongate, more than half the length of the shell; margin defined, but with no 
exterior expansion preserved. Anterior end short, narrowly rounded. 
Valves very convex in the middle and above; the convexity declining 
gradually toward the posterior end and abruptly toward the base and ante¬ 
rior. 
Beaks sub-anterior, small, acute and directed forward. Umbonal slope 
convex, not strongly defined, extending to the posterior extremity above the 
middle of its height. 
Surface marked by about forty narrow rays, which are flattened or rounded 
on the middle of the shell, and sub-angular on the anterior and posterior ends. 
Entire surface also marked by closely arranged, lamellose concentric striae, 
which are often aggregated and at intervals produce sub-imbricating lamellae. 
The specimen described has a length of 45 mm. and a height of 20 mm. 
This species is distinguished by its elongate and sub-cylindrical form. The 
specimen described is somewhat vertically compressed so that the height given 
is less than that of the shell in its natural condition. 
Formation and locality. In the Chemung group, at Elmira, N. Y. 
