Figure 1.-Left ilium of Morosaurus robustus Marsh; side view. a. anterior, or pubic, articular surface; b. posterior, or ischiadic, articular surface. Figure 2.-The same; inferior view. a, anterior, or pubic, articulation; b. posterior, or ischiadic, articulation. Both figures one-tenth natural size. Figure 3.-Chevron of Diplodocus longus Marsh; top and side views. articular surfaces; b. anterior process; c. posterior process. Figure 4.-Chevron of another individual; letters the same as in figure 3. All the figures are one-tenth natural size.

a.