924 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
O. hemispherica Wilson, p. 192, text fig. 10, No. 11, pl. 2, fig. 20. 
p. 90, text fig. 10, No. 11, pl. 6, fig. 21. 
O. ovalis Wilson, p. 192. 
p. 90, pl. 8, fig. 20, 21. 
O. platys Wilson, p. 1093, text fig. 10, No. 3, pl. 2, figs. 21, 21b. 
p. OI, text fig. 10, No. 3, pl. 6, figs. 22, 23. 
0. rugosa (Wilson), Geol. Surv. Canada, Bull. 33, p. 51, pl. 3, figs. 8, 9, 1921. 
p. 194, text fig. 10, No. 1. 
p. 91, text fig. 10, No. 1, pl. 8, figs. 22, 23. 
O. (?) rugosa avita (Wilson), Canadian Field Nat., vol. 46, No. 6, 1932. 
p. 138, pl. 2, figs. 6-13. 
p. 195, text fig. 10, No. 2. 
p. oI, text fig. 10, No. 2, pl. 8, figs. 15-19. 
. septata borealis Wilson, p. 195, text fig. 10, No. 6, pl. 2, fig. 15. 
p. 92, text fig. 10, No. 6, pl. 6, fig. 15. 
. sinclairi Wilson, p. 196, text fig. 10, No. 9, pl. 2, figs. 18a, b. 
p. 92, text fig. 10, No. 9, pl. 6, figs. 18, 19. 
. subtriangularis Wilson, p. 196, text fig. 10, No. 5, pl. 2, fig. 22. 
p. 92, text fig. 10, No. 5, pl. 6, fig. 24. 
. tumida Wilson, p. 197, text fig. 10, No. 10, pl. 2, fig. 16. 
p. 93, text fig. 10, No. 10, pl. 6, fig. 16. 
. wagneri robusta Wilson, p. 198, text fig. 10, No. 8, pl. 2, figs. 25a, 25b. 
p. 94, text fig. 10, No. 8, pl. 6, figs. 27, 28. 
Of OO 2 Os = 
GPIKINA sp. 1 
Plate 242, A, figures 1-5 
This is a species characterized by low convexity and not strongly pronounced 
geniculation. It somewhat resembles O. subplanodorsata but is more concave. 
It is also suggestive of O. varia, but the place of geniculation is farther from the 
beak and the ornamentation is different. 
Measurements in mm.—117849, length 14.5, brachial length 13.4, midwidth 
15.1, hinge width 15.9, thickness 3.3, height 4.8. 
Figured specimen.—117849. 
Horizon and locality.—Benbolt formation in Virginia: On the east bank of a 
sinkhole south of Lakeview Church on Virginia Highway 71, southwest quar- 
ter of east-central subquad., Moll Creek (T.V.A. 196-SE) Quadrangle; 14 miles 
southwest of Rye Cove, Clinchport (T.V.A. 188-NW) Quadrangle. 
OPIKINA sp. 2 
This is a small species elongate or subquadrate, of modest height and depth 
and with geniculation occurring at Io to 13 mm. anterior to the beak. It is sug- 
gestive of O. parvula, but the Oklahoma shell is not so deep and is somewhat 
differently proportioned. This Oklahoma species is smaller than O. varia and 
differently proportioned. 
Measurements in mm.—117850, length 16.5, brachial length 15.6, midwidth 
16.2, hinge width 13.8, thickness 3.0, height 5.1. 
Described specimen—117850. 
