VI.] THE COMMON FROG. 93 



apes {Galago), and still more so in a third half-ape 

 {Tarsms), from the island of Banca. Now it is 

 absolutely impossible to believe that a special genetic 1 R 

 affinity connects together by a peculiarly common « » 

 descent, Half-Apes and Frogs 1 We are then driven 

 to the conclusion that we have here again a striking 

 similarity of structure in two instances which are quite 

 independent in their origin. 



That the power of rapid and prolonged "jumping " 

 does not carry with it as a necessary consequence the 

 elongation of ankle-bones, is demonstrated by the 

 fact that in other animals which, to say the very least, 

 jump no less than do these half-apes — as for example 

 in the kangaroos, jumping shrews, and jerboas — it is 

 not bones of the ankle but bones of the foot proper, \ 

 which take on an augmentation in length. 



