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Show 166 DR. C. W. ANDREWS ON FOSSIL BIRDS [Jan. 19, marked towards the lower end, where the bone widens out towards the distal articulation. Tlxe popliteal fossa is deep, and there are several pneumatic foramina (/m./.) opening into it; it is more strongly defined and extends further up the bone than in JZpyornis. Tlxe trochlear surface is rather flattened, and is separated from the intercondylar groove by a well-defined angle. The broad intercondylar groove is marked with two or three deep pits for the attachment of ligaments. The inner condyle is much as in JSpyornis, but in the outer the fibular surface is broader and the short ridge forming its supero-internal border is much more px-ominent. Near the middle of tlxe shaft and on its postero-external border-there is a small nutritive foramen. The Tibio-tarsus (Plate V. figs. 4 & 5).-The tibio-tarsus is relatively more slender than that of JEpyornis mitlleri, and the antero-postex-ior compression of tlxe shaft is a little less marked. The cnemial crests are well developed and rise high above the articular surface. Immediately beneath tlxe rim of the hinder-edge of the proximal articulation there is a deep concavity into which several foramina, probably pneumatic (pn.f), open. The distal portion of the shaft is greatly flattened from before backwards, and its anterior face is slightly concave from side to side. This concavity is deepest at the groove for the extensor tendons, which runs farther up the bone than in JEpyornis and is not quite so near the inner margin. The groove is bordered externally by a long and px-ominexxt x-idge, and on the inner side by a short projection (fig. 5, t), which is evidently the partially ossified base of tlxe otheiwise tendinous bridge over the extensor tendons. The distal articulation is almost exactly like that of the tibia of JEpyornis mulleri. The so-called middle trochlea, a slight convexity between the outer and inner condyles, is very slightly developed. The post-condylar processes are shax'ply marked off from tlxe condyles, and the outer at least projects more than in jEpyornis. The Fibula (Plate Y . fig. 6).-The fibula as far as preserved is 160 m m . long. Its upper end is large, and in correlation with tlxe large size of the fibular surface of the femur it bears a large articular surface which extends a considerable distance down tlxe outer side of the shaft. The surface for articulation with tlxe fibular prominence of the tibia is oval and deeply concave. About a third of the length of the bone fx-om its distal end thex-e is a prominent tubercle for- the insertion of the biceps cruris. The Tarso-metatarsus (Plate Y . figs. 7 & 8).-The tarso-meta-tarsxrs is a comparatively slender bone, and in general structure corresponds entirely with that of one of the smaller species of JEpyornis, e. g. JE. hildebrandti as described by Burckhardt. In the proximal articulation the surface for tlxe inner condyle of the tibia is much the larger, and is much wider antero-posteriorly than that for tlxe outer condyle; there is no intercondylar process, but, on the other hand, there is a slight median concavity for the |