Ancestors 1 5 



ably at least an indirect descendant of the Phororhacos. 

 The Seriema defies exact classification, sharing characters 

 of cranes, bustards, and eagles. Its beak and inner 

 claw are like those of a bird of prey, while in form of 

 body, and in the other claws of the toes, and in the legs 

 it is crane-like. One of these birds which I have ob- 

 served for years in captivity is as gentle and as fearless 

 as a bird can be. It will chase insects and field-mice 

 outdoors in the Zoological Park, and will occasionally 

 stalk solemnly into m}^ office and, coming close to my 

 desk, watch me closely. It has most beautiful gray- 

 blue e3'es, with long eyelashes (Fig. 199), and if the 

 birds of past ages were as comel}^ and as lovable as this 

 interesting species, I regret that only their fossil bones 

 are left to us. As the Seriema nms down and kills a 

 mouse, so the giant Phororhacos, doubtless, overtook 

 and slew creatures as large as a deer. Its skull (Fig. 7) 

 is drawn to the same scale as that of the living Seriema 

 (Fig. 8). 



The evolution which has gone on since these epochs 

 of old, bringing into being the wonderfully varied forms 

 of penguin, ostrich, albatross, peacock, and humming- 

 bird, may be summed up in two words which it is well 

 to know and remember, — Adaptive Radiation. This is 

 the spreading out or radiating of bird-forms descended 

 from the ancient stem, into all parts of the earth, each 

 coming into contact with a particular environment, to 

 adjust itself to which, its various organs and parts exer- 

 cise different functions, until the friction of the "struggle 

 for existence" has moulded each to its particular niche. 



