80 ANIMALS OF THE PAST 



able in many ways. Hesperornis, the western 

 bird, was a great diver, in some ways the great- 

 est of the divers, for it stood higher than the 

 king penguin, though more slender and-grace- 

 ful in general build, looking somewhat like an 

 overgrown, absolutely wingless loon. 



The penguins, as everyone knows, swim with 

 their front limbs — we can't call them wings — 

 which, though containing all the bones of a 

 wing, have become transformed into powerful 

 paddles ; Hesperornis, on the other hand, swam 

 altogether with its legs — swam so well with 

 them, indeed, that through disuse the wings 

 dwindled away and vanished, save one bone. 

 This, however, is not stating the theory quite 

 correctly ; of course the matter cannot be actu- 

 ally proved. Hesperornis was a large bird, up- 

 wards of five feet in length, and if its ances- 

 tors were equally bulky their wings were quite 

 too large to be used in swimming under water, 

 as are those of such short- winged forms as the 

 Auks which fly under the water quite as much 

 as they fly over it. Hence the wings were 

 closely folded upon the body so as to offer the 

 least possible resistance, and being disused, they 



