452 



CHORD ATA. 



quadrate has only a single articulation with the skull. The 

 Ratitce illustrate discontinuous distribution. The ostrich 

 (Striithid) is found in Africa and South- Western Asia. It 

 has only two toes — a large fourth and a small fifth. 1 he 

 American ostrich {Rhea) has three toes and is found in 

 South America. The Cassowary {Casuarius) and Emu 

 {Dromceiis) are found in the Australian region and the small 

 Kiwi {Apteryx) in New Zealand. On this latter island are 

 also found the remains of the recently extinct Moas {Din- 

 ornis), huge wingless birds. Others have been found in 

 Madagascar. 



Fi^- 319.— The Kiwi {Apteryx) x i. 



A " wingless " bird of New Zealand. The wings are vestigial 

 and hidden below the feathers. 



Order II. — Carinatce. 



The Carinatce comprise the remainder of modern birds. 

 Considering the enormous number of species and wide dis- 

 tribution, they present remarkably few structural differences 

 which are available for classification. In one or two fossils, 

 such as the Cretaceous Hesperornis and Ichthyornis^ teeth still 

 survive. 



They are classified by reference to the arrangement of 

 the feathers, the structure of the skull and of the alimentary 

 organs. 



