188 HISTORY OF THE HUMAN BODY 



a single long bone, showing at least a tendency in a similar 

 direction. Here the matter must rest for the present from lack 

 of further evidence, but the solution may be found at any 

 time, as has happened in so many other cases, through the 

 discovery of the fossil remains of some transition form. The 

 pick of the geologist may unearth the key to this problem, a 

 true palseontological Rosetta stone, by the aid of which the 

 discrepant records written on fin and foot may be deciphered 

 and brought into harmony.* 



* Within the past few years a number of fossil Polypteri have been dis- 

 covered in the Triassic beds along the shores of Lake Tanganyika, in the 

 waters of which their living descendants are still found. This would seem 

 a favorable locality from which to expect results. 



