61 
Dr. Renshaw dealt in a very interesting manner with the 
ostrich and giraffe. The ostrich is essentially a bird of the 
desert. Its prominent eyes and long neck ensure safety from 
attack. When the ostrich is young the legs and neck are not 
unduly elongated, and it therefore seems probable that the 
ostrich is descended from a bird not speciallyadapted to the des- 
ert and that the adaptation arose gradually during the history 
of the race to meet new circumstances of environment. Like 
the domestic fowl it has lost the power of flight, its wings 
being used only to steady itself in running, for which activity 
its long stout legs seem to have been specially developed. 
The ostrich has a very small foot for, during its racial history, 
it has lost two of its original digitals, with great gain, how- 
ever, to its running powers. The remaining digits are large 
and well padded. From the skeleton of the ostrich it is 
seen that the breast-bone is not keeled as in birds adapted 
for flight. The keel seems to have disappeared because the 
muscles operating the wings gradually ceased to be fully 
functioned ; hence the keel which originally served as a 
point of attachment for the large muscles of the wings grad- 
ually became less and less pronounced and finally non- 
existent. 
The giraffe is an animal whose entire organization is com- 
pletely adapted to its environment. Its long mobile thick- 
ened upper lip and the ability to close completely the nostril, 
serve as a protection against the thorns on the acacia tree, 
on the leaves of which it feeds. The neck would seem 
to have become long in the course of its racial development 
for there are only seven vertebral bones in the neck, and 
the neck of the young giraffe is quite short. The high withers 
of the giraffe allow of suitable attachment for the supporting 
ligaments of the long neck and also serve to secure speed 
and sure-footedness. Similar full treatment was accorded 
to the oryx, the bubal, the gazelle, and interesting reference 
was made to the jerboa, the desert fox, black stork, and 
the wild dog. 
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