PART I 

 STRUCTURE OF BIRDS 



CHAPTER I 



Skeleton, Feathers, Wings, Wing Expanses, Beaks 



This subject has been worked out by anatomists 

 in the utmost detail, and we have no desire to 

 follow the scientists in their deeper researches. 

 Our aim is merely to give a concise view of the 

 general aspects for the use of those who have 

 neither time nor opportunity for a wider study. 



To take the skeleton first : — This is seen at 

 once to be constructed on lines which differ 

 essentially from those of an animal destined for a 

 terrestrial life ; it is formed for two supreme ends, 

 lightness and strength. The shape is that of a 

 ship ; the sternum or breast bone, forming the keel, 

 runs to a thin edge in front, and serves to cut the 

 air exactly as the prow of a boat cleaves the 

 water. The bones, powerful as they are, are for 

 the most part hollow, and their lightness may be 

 estimated when it is stated that a pelican five 

 feet in length, and weighing 251b. in the flesh, 

 possessed a skeleton of barely 23 ounces. Again, 

 the pectoral muscles which control the wings are 

 of enormous power ; these facts taken in con- 

 junction with the great lung capacity and the 

 disposal of air-sacs in various parts of the body, 



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