LAIMA K CLAS THEORY SOF SDESCENE a7 
the giraffe, without standing on its hind legs, raises 
its head and reaches six meters in height (almost 
twenty feet). 
“Among the birds, the ostriches, deprived of the 
power of flight, and raised on very long legs, prob- 
ably owe their singular conformation to analogous 
circumstances. 
“The result of habits is as remarkable in the car- 
nivorous mammals as it is in the herbivorous, but it 
presents effects of another kind. 
“ Indeed, those of these mammals which are habit- 
uated, as their race, both to climb as well as to 
scratch or dig in the ground, or to tear open and kill 
other animals for food, have been obliged to use 
the digits of their feet; moreover, this habit has 
favored the separation of their digits, and has formed 
the claws with which they are armed. 
“But among the carnivores there are some which 
are obliged to run in order to overtake their prey; 
moreover, since these need and consequently have 
the habit of daily tearing with their claws and bury- 
ing them deeply in the body of another animal, to 
seize and then to tear the flesh, and have been enabled 
by their repeated efforts to procure for these claws a 
size and curvature which would ne interfere in 
walking or running on stony soil, has resulted in 
this case that the animal has ees ee to make 
other efforts to draw back these too salient and curved 
claws which would impede it, and hence there has 
resulted the gradual bormation of those special sheaths 
in which ne cats, tigers, lions, etc., withdraw their 
claws when not in action. 
“Thus the efforts in any direction whatever, main- 
tained for a long time or made habitually by certain 
parts of a living body to satisfy necessities called 
out by nature or by circumstances, develop these 
parts and make them acquire dimensions and a shape 
which they never would have attained if these efforts 
