108 THE WANDERINGS OF ANIMALS [CH. 



all Malaya, Papuasia and Polynesia, perhaps, as 

 Darwin pointed out, owing to the absence of monkeys 

 and other noxious, egg-stealing mammals. Flightless, 

 large-sized pigeons were the recently extinguished 

 Dodo of Mauritius and Bourbon, and the Solitaire 

 (Pezophaps) of Rodriguez. 



Gruiformes or Cranes and Rails are an important 

 order on account of the distribution of the genera, 

 some of which are at least of Oligocene date. Taken 

 as a whole, this order indicates common origin and 

 descent from an equatorial belt of land when South 

 America, Africa and India were still more or less 

 connected ; after this time the development of 

 entirely Old World families becomes marked. 



Rails are cosmopolitan, but interesting because 

 of the tendency of reduction of their wing power. 

 Beginning for instance with birds like the Weka 

 Rails (Ocydromus) of New Zealand, they are liable 

 to become flightless, with a much-reduced keel of the 

 breastbone. This has happened, especially on small 

 islands, e.g. Chatham Island with Diaphorapteryx, 

 Rodriguez with Erythromachus, Mauritius with 

 Aphanapteryx, all of which have died out recently. 

 Although they are structurally so much alike, that 

 we might unhesitatingly put them into one genus, 

 if they did occur together, they have each received 

 a second generic name ; rightly though, because they 

 must have developed independently of each other 



