278 PALEOZOIC PALEONTOLOGY. 
ORTHOTHETES WOOLWORTHANA (Hall). 
Plate XXVIL., Fig. 5. 
1859. Strophomena woolworthana Hall, Pal. N.Y., vol. II1., p. 192, 
pl. 1%, figs. 1 a-t, 2 a-c. 
Description.—Shell longitudinally semi-elliptical, hinge-line equal- 
ing the greatest width. Pedicle valve slightly convex or flattened 
on the umbo, concave toward the front, marked interiorly by a broad, 
flabellate, muscular impression; the beak elevated, but scarcely pro- 
jecting beyond the cardinal line; cardinal area flat, rather high; 
delthyrium broadly triangular, closed by a deltidium. Brachial valve 
convex, flattened on the umbo, most elevated toward the front. Surface 
of both valves marked by angular, raised, radiating strie, which are 
crossed by fine, concentric strize and by a few more conspicuous lines 
of growth. 
The dimensions of an average specimen are: length, 32 mm.; 
width, 34 mm. 
LEPTAENA RHOMBOIDALIS Wilck. 
Plate XXVII., Fig. 9. 
See, also, pp. 228, 302, 325, 366. 
This species is not a common one in the Coeymans limestone fauna. 
The specimens observed are of medium size, one of the most perfect 
ones being 17 mm. long by 24 mm. wide. As compared with the 
Decker Ferry representatives of the species, they are larger, with pro- 
portionally-finer concentric wrinkles and less sharply-defined radiating 
strie. 
SCHIZOPHORIA BISINUATA Nl. Sp. 
Plate XXXI., Figs. 12-14. 
Description.—Shell subcircular or transversely subelliptical in out- 
line, the hinge-line about one-half the width of the shell. Pedicle 
valve convex, its greatest depth usually posterior to the middle, from 
which point it curves abruptly to the cardinal margins, but more 
gently to the sides and to the front, where there is a broad, shallow, ill- 
