Figure 1.-Tooth of Laosaurus altus Marsh; front view. Figure 2.-The same, side view. Both twice natural size. Figure 3.-Bones of the left hind leg of Laosaurus altus Marsh; one-eighth natural size; il. ilium; is. ischium; p. pubis; p'. post-pubic bone; f. femur; t. tibia; f. fibula; a. astragalus; c. calcaneum; I. first metatarsal; IVmt. fourth metatarsal.

Figure 1.-Pelvis of Hesperornis regalis Marsh (Cretaceous); seen from the left, one-fifth natural size.

Figure 2.-Pelvis of Laosaurus altus Marsh; seen from the left, one-sixth natural size.

Figure 3.-Pelvis of Morosaurus grandis Marsh; seen from the left, one-sixteenth natural size.

The signification of the letters is the same in all the figures, viz: a. acetabulum; il. ilium; is. ischium; p. pubis; p'. post-pubis.