The Bustards 341 



formes. Structurally their most important characters are the three toes, absence 

 of an oil-gland, the presence of after-shafts to the contour feathers, and the split 

 form (schizognathous) of the palate and circular (holorhinal) nostrils. Certain 

 of the forms possess a peculiar gular pouch, or a highly dilatable esophagus, 

 which may be inflated at the will of the bird, of which more will be stated later. 

 They are all confined to the Old World and are comprised in a dozen genera 



FIG. 112. Great Bustard, Otis tarda. 



and about thirty-five species. Although they possess ample wings they are 

 essentially terrestrial in their habits, frequenting chiefly dry, open plains and 

 steppes, on which account they might appropriately be called, as Gadow has 

 suggested, the Steppe-Rails. Their strong legs and feet well adapt them to 

 walking and running, which latter they do with great swiftness, though readily 

 taking to wing when pressed. That the group is one of considerable antiquity 

 is shown by the fact that two fossil forms are known from the middle Tertiary. 

 The Great Bustard (Otis tarda) may be regarded as typical of the first genus 

 we shall consider. It is the largest European bird, an adult male being about 

 forty-five inches long and weighing in the neighborhood of thirty pounds, while 

 the female is some ten inches shorter and correspondingly lighter. In color the 

 male is sandy rufous above, broadly banded with black across the back, the 



