Extracted from the Proceedings of the Academy of Natural Sciences, April, 1876. J 



On a Gigantic Bird from the Eocene of New Mexico. — Prof. 

 Cope exhibited a tarsometatarsus of a bird, discovered by himself 

 during, the explorations in New Mexico, conducted by Lieut. G. 

 M. Wheeler, U. S. A. The characters of its proximal extremity 

 resemble in many points those of the order Cursores (represented 

 by the 8truthionid.se and Dinornis), while those of the distal end 

 are, in the middle and inner trochlea, like those of the Gastornis 

 of the Paris Basin. Its size indicates a species with feet twice 

 the bulk of those of the ostrich. The discovery introduces this 

 group of birds to the known faunae of North America recent and 

 extinct, and demonstrates that this continent has not been desti- 

 tute of the gigantic forms of birds, heretofore chiefly found in 

 the Southern Hemisphere faunae. The description is as follows : — 



The hypotarsus is moderately prominent, with broad truncate 

 face, and does not inclose the ligamentous groove of its inner side. 

 Its superior angle is broken away in the specimen. The two fora- 

 mina which pierce the shaft just below the head, are well separated 

 from each other both on the posterior and anterior faces, marking 

 nearlj' equal thirds of the transverse diameter of the bone. The 

 cotyloid cavities for the tibio-tarsus are bounded by an elevated 

 margin, and are separated medially by a single low oblique ridge. 

 The groove of the posterior face is particularly wide, and the inner 

 part of the shaft is thinned, while the outer border is broadly con- 

 vex. The proximal part of the inner border (as far as it is pre- 

 served) is marked with a flat surface which is roughened with 

 ridges, which is perhaps the sutural articulation of the proximal 

 end of the metatarsus of the hallux. No such surface exists on 

 the corresponding bone of the ostrich or emeu. Only two of the 

 free distal phalangeal extremities are preserved. The shaft is 

 broken, showing that its interior is filled with cancellous tissue. 

 The free extremities are remarkable for the great inferior extent of 

 the articular trochlear face. The median is strongly grooved with 

 an obtuse excavation, and the lateral or bordering ridges are equal 

 and rounded. The groove is continuous with the superior surface, 

 but not with the inferior. There the convergent lateral ridges in- 

 losing the open groove, terminate in an abrupt elevation above the 

 adjacent surface of the shaft. The sides at this point are concave. 

 The inner free condyle has an oblique articular face, the external 

 ridge dropping away internally as in many birds, and produced 

 beyond the inner ridge, distalty. The articular face becomes then 

 a part of a spiral, and is little grooved above, but strongly grooved 



