CLASSIFICA TION OF BIRDS. 687 



The American ostrich (Rhea) is represented by three species in the 

 S. American Pampas. In the Rhea there are three toes, all clawed, 

 and the ischia form a ventral symphysis. There are no clavicles. 

 Only here among Ratitae is there a well-developed syrinx. The caeca 

 are large. The male excavates a shallow nest in the ground, and 

 there, surrounded by a few leaves and grasses, the numerous eggs are 

 usually laid. It seems that the male bird alone hatches the eggs. 

 Single eggs are often laid here and there on the plains, but these are 

 not incubated. 



The Emu (Dramaus} is represented by two species in Australian 

 deserts and plains. The fore-limb is greatly reduced, the feathers have 

 long aftershafts. Nearly related are the Cassowaries (Casuarms) living 

 in the Austral- Malayan region, eight species in the Papuan Islands, one 

 in N.-E. Australia, and one in Ceram. They live in the forests and 

 scrub. The fore- limb is very small, with the shafts of the wing feathers 

 reduced to spines ; the ordinary feathers have long aftershafts. On 

 the top of the skull there is a horny helmet, covering a core of light 

 spongy bone ; this protects the bent head as the bird rushes through the 

 scrub. There are three toes, the inner one with a long sharp claw a 

 formidable weapon. In Emu and Cassowary the clavicles are repre- 

 sented by separate rudiments and the caeca are small. 



The Kiwi (Apteryx) forms a very distinct genus of Ratitae, represented 

 by four species, restricted to New Zealand. It is not larger than a 

 hen, and has simple hair-like or bristle-like feathers, a long bill and 

 terminal nostrils, a very rudimentary wing and no clavicles, and no 

 distinct tail feathers. There are four clawed toes. The caeca are large. 

 It is a nocturnal bird, swift and noiseless in its movements, feeding in 

 great part on earthworms. The egg is very large for the size of the bird. 

 Among the extinct Ratitae are the gigantic Moas (Dinornis\ which 

 seem to have been exterminated in New Zealand in comparatively recent 

 times. The fore-limbs were almost completely reduced, the hind-legs 

 were very large, and some forms attained a height of 10 ft. or even more. 



Another recently lost order of giant birds is represented by remains 

 of dZpyornis found in Madagascar. Some of these indicate birds as 

 large as ostriches, but eggs have been found holding six times as much 

 as that of an ostrich. 



We may think of the Ratitae, according to W. K. Parker, as "over- 

 grown, degenerate birds that were once on the right road for becoming 

 flying fowl, but through greediness and idleness never reached the 

 'goal,' went back, indeed, and lost their sternal keel, and almost lost 

 their unexercised wings." 



2. Division ODONTOLC^E. Represented by Hesperomis from N. 

 American Cretaceous strata, somewhat like a swimming ostrich, 

 with sharp teeth sunk in a groove, with saddle-shaped cervical 

 vertebrae as in modern birds, with a rudimentary fore-limb, but 

 with a powerful swimming leg. In an English representative 

 Enaliornis the vertebrae are chiefly biconcave. These extinct 

 birds have many Ratite skeletal characters, and they have also 

 interesting resemblances to some old-fashioned living Carinatae, 

 notably the divers (Colymbidae). 



