PHORORHACOS  , the best-known genus of the

extinct Patagonian Stereornithes (see BIRD: Fossil) . Among the bones found in the strata of the Santa Cruz formation (now considered as mainly of mid-Miocene date) was the piece of a mandible which F . Ameghino described in 1887 as that of an edentate mammal, under the name of Phorysrhacos longissimus (Bolet . Mus. de la Plata, i . 24) . In 1891 (Rev . Argent . Hist . Nat. i . 225) (From life-size model in Brit . Mus . Nat .

Hist.)

Skull of Phororhacos, longissimus . he amended the name and recognized the bone as that of a bird, Phororhacos, which with Brontornis and others constituted the family Phororhacidae . About six species of the type genus are now known, the most complete being Ph. infiatus, with skull, mandible, pelvis, limbs and some of the vertebrae . These birds were at first considered as either belonging to the Ratitae, or at least related to them, until C . W . Andrews, after much of the interesting material had been acquired by the British Museum, showed the gruiform affinities of Phororhacos (Ibis, 1896, pp . 1-12), a conclusion which he was able to further corroborate after the clearing of the adherent stony matrix from the skulls (Tr . Z . S . 19ox, xv. pp . 55-86, pls . 14-17) .

The skull of Ph. longissimus is about 2 ft.

long and to in. high; that of Ph. inflatus is 13 in. long, and this creature is supposed to have stood only 3 ft. high at the middle of the back . The under jaw is slightly curved upwards and it contains a large foramen as for instance in Psophia and in Mycteria . The strongly hooked upper beak is very high, and very much compressed laterally . The palate is imperfectly desmognathous, as in Dicholophus, with an inconspicuous vomer . The quadrate has a double knob for its articulation with the skull, and basipterygoid processes are absent . What little is known of the shoulder-girdle (breastbone still unknown) points to a flightless bird, and so do the short wing bones, although these are stout . The pelvis has an ischiadic foramen . The hind limbs are distinctly slender, the tibia of Ph. inflatus being between 15 and 16 in. in length . For further detail see F . Ameghino, " Sur les oiseaux fossiles de la Patagonie," Bolet. inst. geogr. argentino, xv., chs . II and 12 (1895); F . P .

Moreno and A . Mercerat, Catdlogo de los pdjaros f6siles de la Republica

Argentina, An . Mus . La Plata (1891; with 21 plates) . (H . F .