DEVONIAN FAUNAS. d67 
ORTHOTHETES PANDORA (Bill.). 
See, also, pp. 373 and 380. 
186%. Streptorhynchus pandora Hall, Pal. N. Y., vol. IV., p. 68, 
pl. 4, figs. 11-19, pl. 9, figs. 18-25, 27. 
Description.—Shell semi-circular or ‘semi-elliptical in outline, 
hinge-line equaling the greatest width of the shell, cardinal angles 
nearly rectangular. Pedicle valve convex, greatest elevation at the 
beak, from which point the surface slopes away regularly with a 
slight convex curve to the lateral and anterior margins; beak obtuse, 
not incurved; cardinal area rather high, sloping a little posteriorly, 
flat or slightly concave. Brachial valve depressed-convex, flattened 
toward the cardinal angles. Surface of both valves marked by 
numerous, fine, strongly-elevated, radiating costee, which increase by 
bifurcation and by intercalation. 
The dimensions of a nearly-perfect pedicle valve are: length, 10 
mm.; width, 14 mm.; convexity, 3 mm. 
Remarks.—More or less fragmentary specimens of this species have 
been found in the Onondaga limestone at several localities in New 
Jersey. 
CHONETES ARCUATUS Hall. 
Plate LI., Fig. 18. 
1867. Chonetes arcuata Hall, Pal. N. Y., vol. IV., p. 119, pl. 20, 
figs. 7 a-f. 
Description.—Shell semi-circular or semi-elliptical in outline; 
hinge-line equaling the greatest width; cardinal extremities angular. 
Pedicle valve gibbous, somewhat depressed toward the cardinal angles, 
a little flattened along the median line from the beak to the anterior 
margin; the beak strongly incurved, the cardinal margins sloping 
gently from the beak to the cardinal extremities, bearing about seven 
or eight spines, pointing in a shghtly oblique direction outward, on 
each side of the beak. Surface marked by fine, radiating coste, 
which increase by intercalation and rarely by bifurcation, about one 
hundred being present on the margin of a shell 17 mm. wide, and 
