344 
PALAEONTOLOGY OF NEW YORK. 
Strophomena Conradi, sp. nov. 
PLATE IX A, FIG. 3; AND PLATE XX, FIGS. 32, 33. 
Shell semiovate in outline; hinge-line straight and forming the greatest 
diameter of the shell. Cardinal area narrow on both valves; broader on the 
pedicle-valve and but slightly elevated at the umbo. Delthyrium covered ; 
deltidium perforated at the apex. Pedicle-valve convex in the umbonal 
region, but becoming deeply depressed and concave over the middle of the 
shell and again elevated about the margins. The depression of the valve is 
most conspicuous along the median line and on the anterior margin where it 
produces a subnasute extension. The brachial valve is flat or slightly con¬ 
cave at the umbo, becoming convex over the pallial region; it reaches its 
greatest convexity at about the middle of the shell and is thence deflected 
gradually in the median line and more abruptly on the lateral slopes. 
Surface of the shell covered with radiating striae, arranged in fascicles 
of 4 to 7 fine ones between each pair of coarser ones There are no con¬ 
centric rugae on either valve, but the radiating striae are crossed by ex¬ 
ceedingly minute concentric lines. 
Width of the original specimen along the hinge, 23 mm.; greatest length, 
19 mm. 
Trenton limestone. JacJcsonburg, N. Y. 
Strophomena Winchelli, sp. nov. 
1883. Strophomena nutans, Hall. Rept. State Geologist N. Y. for 1882, expl. pi. (ix) 39, figs. 10,12-14. 
PLATE IX, FIGS. 10,12-14 ; PLATE XX, FIG. 26. 
Shell elongate semiovate; strongly convexo-concave. Hinge-line straight and 
making the greatest diameter of the shell. Cardinal angles sometimes ex¬ 
tended. Pedicle-valve with a moderately broad area and deltidium; apex 
slightly elevated, the valve becoming deeply concave over the pallial region 
and reflected at the margins. The teeth are strong and divergent, and from 
their bases extend elevated curving ridges which form the margin of the 
subcircular or subovate muscular area. Diductor scars broad, enclosing an 
