< HORDATA 



339 



Casuaris ; and the emus, Dromaius. Nearly all the bom 

 heavy and contain marrow instead of air spaces as in flying 

 birds. The extinct, gigantic moas (Fig. 335) of Australia and 

 New Zealand belong to this group; they appear to haw be- 

 come extinct since man lived in those countries. The African 



FlG. 337. Apteryx australis ; skeleton. (After Parker and Haswell.) 



ostrich supplies the valuable feathers of commerce, and now 

 ostrich farms are maintained in this country in California. 

 These birds may attain a height of over two meters and a 

 weight of a hundred kilos. The eggs are from twelve to fifteen 

 centimeters long and require seven or eight weeks for incubation. 



