362 GEOGRAPHICAL ZOOLOGY. [part iv. 



intermediate between the Anserine birds on the one side and 

 the Storks and Herons on the other." The pterolysis according 

 to Nitzsch is " completely stork-like." 



General Remarks on the Distribution of the (h^allcc, or Wading 

 and Running Birds. 



The Waders, as a rule, are birds of very wide distribution, 

 the four largest families Kallidae, Scolopacidae, Charadriidae and 

 Ardeidae, being quite cosmopolitan, as are many of the genera. 

 But there are also a number of small families of very 

 restricted distribution, and these all occur in the two most 

 isolated regions, the Neotropical and the Australian. The 

 Neotropical region is by far the richest in varied forms of 

 Waders, having representatives of no less than 15 out of the 19 

 families, while 7 are altogether peculiar to it. The Australian 

 region has 11 families, with 1 peculiar. The other two tropical 

 regions each possess 11 families, but none are peculiar. The 

 Palaearctic region has 10, and the Nearctic 7 families. No less 

 than three families — Chionididae, Thinocoridae, and Cariamidae — 

 are confined to the Temperate regions and highlands of South 

 America ; while four others, — Aramidse, Psophiidae, Eurypygidae 

 and Palamedeidae, — are found in Tropical America only ; and 

 these present such an array of peculiar and interesting forms as 

 no other part of the globe can furnish. The Phcenicopteridae or 

 Flamingoes, common to the Tropical regions of Asia, Africa and 

 America, but absent from Australia, is the only other feature 

 of general interest presented by the distribution of the Waders. 



The Order contains about 610 species, which gives about 32 

 species to each family, a smaller average than in the Gallinae 

 or Accipitres, and only about one-fourth of the average number 

 in the Passeres. This is partly due to the unusual number 

 of very small families, and partly to the wide average range of 

 the species, which prevents that specialization of forms that 

 occurs in the more sedentary groups of birds. 



