we 
THE SEA-BIRDS. ah 
small wings as feet, which converts them for the moment into 
quadrupeds. 
There are species which live constantly on the water. The 
Cape Pigeon, which is distinguished by alternate black and white 
marks on its back, follows in the wake of a vessel for days together, 
where, in the eddy, he finds numberless little mollusca. The 
name of petrel, or /z¢t/e Peter, contains an allusion to the miracle 
of St. Peter walking on the water. 
All web-footed birds can swim with equal elegance and ease. 
THE CAPE PIGEON. 
(Procellaria Cafents.) 
Ducks and goosanders -balance themselves gracefully on the surface 
of the water, and play tranquilly in the midst of the most rapid 
streams. These birds have tails shaped like the keel of a boat ; 
their feet, as we have seen above, serve for oars, and their wings, 
partly spread, furnish sails for this little living vessel. 
Those species of birds which have not the faculty of flight are 
the most dexterous in swimming and diving. Their wings, which 
are usually short, act as fins, so that the bird possesses four oars, 
two in front and two behind, exactly like a fish. By this arrange- 
ment their swimming powers are not very inferior to the fish upon 
which they prey, save that they cannot remain long under water, 
nor yet dive deep, unless, like the northern geese, they can descend 
