No. 633] INHERITANCE IN THE OSTRICH 299 



in the course of its phylogeny, remains to be noticed, as a 

 further instance of the responsive power of the skin. 

 Near the mesotarsal ankle-joint occurs a strong, elon- 

 gated, hereditary callosity covering the median part of 

 the broad, proximal end of the tarso-metatarsus (Fig. 

 5). This pad would naturally be used if the bird rested 



squarely upon its tarsus and foot when crouching, the 

 weight being mainly on the ankle. The ostrich however 

 makes little or no use of it, for even in young chicks 

 scarce! v any evidence of contact with the ground can be 

 observed. Somewhat to the inside there appears a new 

 callous thickening, which begins to form by the time the 

 chicks are a month or two old, and remains as the func- 



