The third metatarsal, usually the largest and the most robust throughout, here diminishes in size upward, and takes a subordinate, posterior position, as in birds. The correspondence between the metatarsals of the bird and reptile are here as strongly marked as in the tibial and their accompanying elements, above described.
In figure 3, the three phalanges represented belong with the second metatarsal, and were found together in place.
The three metacarpals represented in figure 4 were found together in position, near the remains of the hind limb here described. Their very small size indicates that they may possibly belong to a smaller individual, but, with this exception, there is no reason why they do not pertain to the same specimen as the hind foot.
The remains of the present species here described were found in the Ceratops beds of Colorado.
Two other species, apparently of the same genus, are represented by various specimens from the same horizon, in Montana. One of these, which may be called Ornithomimus tenuis, was about twice the bulk of the present form. The third metatarsal was much more compressed transversely, both in the shaft and distal end. The bone was also much more slender medially than in the above species. The transverse diameter of this metatarsal at its distal end was 30mm., and the antero-posterior diameter, 35mm
A third species, much larger, may be called Ornithomimus grandis. The third metatarsal was about 600mm in length, and its distal end 90mm in transverse diameter, and 80mm in antero-posterior diameter.
These various remains represent a distinct family, which may be called the Ornithomimidæ.
Barosarus lentus, gen. et sp. nov.
A new genus of the Sauropoda is indicated by various remains of a very large reptile secured by the writer during the past season. The most characteristic portions examined are the caudal vertebral, which in general form resemble those of Diplodocus. They are concave below, as in the caudals of that genus, but the sides of the centra are also deeply excavated.
In the anterior caudals, this excavation extends nearly or quite through the centra, a thin septum usually remaining. In the median caudals, a deep cavity on each side exists, as shown in figures 1 and 2, on page 86.
