64 ON MODIFICATIONS IN THE STRUCTURE OF DIVING ANIMALS. 



enabled us, a priori^ to predict that the bird possessed the peculiar 

 habits which have given it its trivial name. This ridge extends 

 the whole length of the keel in the water-ouzel; and in this 

 point, as well as in the lesser relative depth of that process, and in 

 the greater relative breadth of the lateral portions of the sternum, 

 and in its more nearly circumscribed posterior emarginations, the 

 bird in question differed from allied species of dissimilar habits. 



