PLATE IX. 3D 
Oxpoius TETONENSIS Walcott (p. 417). 
Fieure 5. A ventral valve, the type specimen, with the anterior portion of the shell exfoliated, from Locality 4e, 
Middle Cambrian limestone, Teton Mountains, Wyoming. U.S. Nat. Mus. Cat. No. 51639a. 
5a. Dorsal valve associated with specimen represented by figure 5. U.S. Nat. Mus. Cat. No. 51639b. 
5b. Outline of the two valves, showing their convexity. Drawn from specimen associated with specimens 
represented by figures 5 and 5a. U.S. Nat. Mus. Cat. No. 51639c. 
5c. A small ventral valve from Locality 4m, Middle Cambrian sandstone in the Teton Mountains, Wyoming. 
U.S. Nat. Mus. Cat. No. 35220a. 
5d. Dorsal valve associated with specimen represented by figure 5c. This shell may belong to some other 
species. U.S. Nat. Mus. Cat. No. 35220b. 
OBoLuS WorRTHENT Walcott (p. 421). 
{Text figs. 39A-D, p. 421.] 
Figure 5e. A very finely preserved interior of a small dorsal valve, the type specimen, from Locality 54u, Middle 
Cambrian limestone, 2 miles southeast of Malade, Idaho. U.S. Nat. Mus. Cat. No. 51638a. Copied 
from Walcott [1908d, Pl. VII, fig. 17]. 
