CHAPTER XIX. 



MOEPHOLOGY. 



IN the last chapter the question was asked, whether the 

 truth that every organism has been specially adapted 

 to the conditions of its life will suffice to account for all 

 the facts of the distribution of the various species of 

 organisms through the regions they inhabit ; and we have 

 seen that although every organism is adapted to its habitat, 

 yet this law of adaptation will not account for the facts 

 of distribution. We have now to consider another and 

 a parallel question. 



We know that the form and structure of every organ in 



an organism is adapted to its function : thus, for instance, 



every carnivorous animal has carnivorous teeth. It neces- 



Func- sarily foUows from this, that the organs are aU. functionally 



adapta. adapted to each other : thus, every carnivorous animal has 



tions. not only carnivorous teeth, but a carnivorous stomach, and 



such an organization of the muscles of the legs and jaws 



as enables it to seize, kill, and tear its prey. So that these 



three — teeth, digestive organs, and muscular organs — are 



each adapted to the carnivorous life, and to each other. 



And besides these purely functional adaptations, there are 



Structural structural adaptations ; such as — to mention what is, per- 



adapta- haps, the most obvious instance — the adaptation of the 



forms of the bones to the forms and pressures of the mus- 



Is all mor- cles. ISTow, the question we have to consider is, whether 



explioaijle these laws of structural and functional adaptation will 



Ly the law account for all the facts of morphology, or whether the 



tioii? morphology of any particular species is a resultant from 



