THE CHALK PERIOD 



during which the wings once in existence had become 

 more and more useless, till they had dwindled to a mere 

 nothing. But the Hesperornis had enormously strong 

 legs, which were used as paddles, and their efficiency was 

 increased by the bones of the foot being so joined to 

 the leg as to turn edgewise in the water when brought 

 forward. Any one who has ever paddled a Canadian 

 canoe will appreciate the advantage of this. But this 

 was not all, for the legs were so joined to the body- 

 frame as to stand out nearly at right angles (like a pair 

 of oars), instead of standing under the body as walking 

 legs do. Apparently walking as well as flying had been 

 abandoned, and this bird had become a diver and 

 swimmer merely. The head, neck, and body were long, 

 and admirably shaped for plunging through the water. 

 Favoured by the powerful hind limbs, the Hesperornis 

 must have been very swift both on and under the 

 water, and a formidable enemy to the fishes on which 

 it preferred to feed. Its jaws were armed with teeth 

 set in a groove, and, like the jaws of snakes, were 

 separable so as to admit large prey. As these strange 

 birds were sometimes six feet long, they must have been 

 able to account for fish and reptiles of considerable size. 

 They probably lived nearly altogether on and in the 

 water. 



The second type of bird, Ichihyornls^ were small birds, 

 scarcely larger than pigeons and a little like terns in 

 appearance. They were splendid fliers, and were armed 

 with teeth set in sockets. Their legs and feet were 

 small and slender, but their wings very strongly devel- 



250 



