256 DAVIS — SYSTEMATIC GEOGRAPHY. [Aprils, 



free oxygen, must be regarded as the long-inherited response to 

 the presence of oxygen in the free state, whether mixed with other 

 gases in the atmosphere or dissolved in the waters of the ocean. 

 Organs of flight, to-day characteristic of many insects and birds, 

 are extraordinary devices for movement through the air ; this may 

 seem a valueless truism to some, but it must be explicitly stated if 

 the ontographic framework is to be thoroughly constructed, and if 

 conscious attention is to be aroused to it. Vocal organs are 

 responses to the extreme eclasticity of the air ; human speech may 

 be reckoned among the responses of modern acquisition under 

 this class. The adoption of blue as one of the primary colors of the 

 spectrum is a modern response to the color of the sky ; a physio- 

 graphic fact that has waited long for its ontographic mate. Pollen 

 grains, spores and innumerable microscopic organisms of great im- 

 portance in the economy of the nature, exhibit in their minuteness 

 a response to the small sustaining power of the winds that bear 

 them about. If climate were here considered as well as these 

 simpler physiographic features of the atmosphere, the number of 

 ontographic responses in this class would be greatly increased. 



The greater buoyancy of water than of air has a notable response 

 in the absence of feet among most of the swimming animals of the 

 ocean. The flying animals of the atmosphere, on the other hand, 

 always have legs to sustain them when they alight on the ground 

 from the little sustaining air. The same contrast between water 

 and air must account for the much greater size of the floating 

 inhabitants of the ocean than of the blown-about organisms of the 

 atmosphere. While the more opaque animals of the sea usually 

 have a darker dorsal and a lighter ventral surface, many of the 

 floating animals find relative safety in imitating the transparence of 

 the waters in which they float. It is the monotony of the cold, 

 smooth, dark and quiet ocean bottom that has doomed it to be the 

 home of the less intelligent organisms, while the variety of the 

 lands has promoted the development of the most remarkable in- 

 stincts and the highest intelligence among their inhabitants. 



The separation of the lands into several large continental 

 masses has led to the division of mankind into races ; and closely 

 associated with this division into races go many peculiarities of 

 government, religion and degree of civilization. All this is most 

 intimately connected with that phase of ontography commonly 

 called political geography ; and yet so arbitrary and irrational is 



