6i8 



BIRDS. 



The extant Neornithes are conveniently distinguished as Ratitse and 

 CarinatEe, but the distinctions do not seem very well grounded, 

 and to most of them there are exceptions. 



Some Co7ttrasts between modern Ratittc and modern Carinata. 



RatiTj^. 



Carinat^. 



Running Birds, with wings more or 

 less degenerate and unused in 

 flight, with a keelless raft-like 

 breast bone. 



The skull is dromseognathous, i.e., 

 the vomer is interposed between 

 the palatines, the pterygoids, 

 and the basi-sphenoidal rostrum. 



The sutures in the skull remain for a 

 long time distinct. 



The long axes of the adjacent por- 

 tions of the scapula and coracoid 

 lie almost in the same hne, or 

 form a very obtuse angle, and 

 the two bones are fused. 



The clavicles are small or absent. 



The ilium and ischium are not united 

 behind, except in adult Rhea 

 and Drotnccns. There is no 

 ploughshare bone. 



The feathers of the adult have free 

 barbs. There is no oil gland. 



Flying Birds, with wings almost 

 always well exercised in flight, 

 with a keeled breast bone. 



(The keel is rudimentary in the New 

 Zealand parrot Stringops, in the 

 exterminated Y) 06.0 [Didus), and 

 in the extinct Aptornis — one of 

 the rails. The penguins do not 

 fly at all, the Tinamou, the 

 Hoatzin, and some other birds, 

 fly very little. 



Except in the Tinamous, the skull is 

 never droma^ognathous, i.e., the 

 vomer is not fused with the 

 neighbouring bones of the pal- 

 ate, and the palatines articulate 

 with thebasi-sphenoidal rostrum. 



The sutures in the skull almost always 

 disappear ver>^ early. 



The scapula and coracoid meet at a 

 sharp angle, and are separate 

 from one another. 



The clavicles are in most cases very 

 well developed. 



The ilium and ischium unite, enclos- 

 ing a sciatic foramen. The ter- 

 minal caudal vertebra; fuse to 

 form a ploughshare bone or 

 pygostyle. 



The barbs of the feathers are gener- 

 ally united. 



I. Division Ratit.^. 



Running Birds with raft-like unkeeled 

 breastbone. 



The African Ostrich [Striithio) is represented by tw^o or three species, 

 at home in the plains and deserts of Africa, and notable for their size 

 swiftness of foot, and beauty. There are but two toes, the third and the 

 fourth, with stunted nails. There are no clavicles. The pubes form 

 a ventral symphysis. The enormous size of rectum and CKca is a 

 unique character. The ostrich is monogamous, and at the breedint^ 

 season the hen lays its eggs, at intervals of two days, in a hollow 

 dug out in the sand by the male. The eggs are incubated hy the parents 

 alternately, the male sitting during the night, but in the hottest regions 



