WINGS AND FEET 
flight, as witness the great auk and pen- 
guins. 
3d. That specialization towards the use of 
the feet alone is probably best adapted for the 
most rapid progression under water, and this 
method may leave the wings undiminished in 
size for use in the air. The apparent exception, 
hesperornis, with powerful feet but with wings 
degenerated to vestiges through disuse, serves 
but to confirm the inference of the superiority 
under water of feet action alone. 
205 
