2326 THE TINAMUS, FLIGHTLESS BIRDS, ETC. 



Although well-developed wings were retained, these were useless for flight; but the 

 metacoracoid was of the elongated form characteristic of flying birds, and thus 

 markedly different from the corresponding bone of the ostrich group. The leg 

 bones of these birds indicate two well-marked generic types, in one of which the 

 legs were long and slender, while in the other they were more massive and relatively 

 shorter; the former type being known as Phororhachis and the latter as Brontornis. 

 Corresponding differences obtain in the form and proportions of the beak. What- 

 ever be the exact serial position of these marvelous birds (all of which may be in- 

 cluded in the single family Phororhachidce) , it is evident they were derived from 

 flying birds quite independently of the modern flightless birds. 



As they may possibly have some connection with the Stereornithes, 

 1 Bird a l tnou gh it is almost as probable they may form a group by them- 

 selves, it may be convenient to mention here certain giant extinct 

 birds from the I^ower Eocene of France, England, and the United States, which 

 constitute the family Gastornithidee. All have a bony bridge at the lower end of the 

 tibia, while in the European Gastornis the component bones of the skull remained 

 separate throughout life, and it is possible that there may have been a large tooth 

 on each side of the upper jaw, while the symphysis of the lower mandible was short. 

 In North America the group is represented by Diatryma. 



THE FLIGHTLESS OR OSTRICH-LIKE BIRDS 



Ratitae 



With the exception of certain specially modified species like the dodo, in which 

 the power of flight has been lost, the existing birds hitherto treated are charac- 

 terized by the circumstance that the breastbone is provided with a strong vertical 

 median keel, to afford support for the muscles necessary for flight, while both the 

 scapula and metacoracoid are separate elongated bones, forming an acute or 

 right angle at their junction. On account of this general presence of a keel to the 

 breastbone, the foregoing orders are brigaded into a single assemblage or sub- 

 class known as the Carinat(Z, which may be anglicized into Carinates. As a rule, 

 the Carinates possess to a greater or less degree the power of flight; and they are 

 further generally characterized by the circumstance that in the pelvis the bones 

 known as the ilium and ischium are united at their outer extremities so as to 

 inclose a foramen;* while the head of the quadrate bone, by which the lower jaw 

 articulates with the skull, is double; and in the palate the vomer (except in the 

 tinamus) is not fused with the neighboring bones, or interposed between them and 

 the rostrum of the sphenoid. On the other hand, in the birds now to be considered 

 the breastbone is invariably devoid of a keel, while the metacoracoid is short and 

 united with the scapula, and the two bones form a very obtuse angle at their junc- 



* This circular foramen or vacuity is shown in the pelvis of the skeleton of the parrot figured on p. 1464 

 of Vol. III. 



