THE SEA-BIRDS. 145 
Lesson, is full of shell-fish, which remain nearly dry at low 
water in small pools. The skimmer keeps waiting close by 
until one of them opens its shell, when he immediately intro- 
duces his wedge. He then seizes the mussel, beats it to pieces 
upon the sand, and devours it with all the pleasure of an epicure 
eating an oyster. He is also very active in sweeping the surface of 
the water, from which he skims, as it were, the smaller fish or 
shrimps. Thus, on all flat sandy shores nothing exists, either 
soft or hard, creeping or swimming, jumping or running, that 
does not find among the strand-birds its peculiar and admirably 
armed enemy, or that can boast of a perfect immunity from 
hostile attacks. 
If we examine the real sea-birds, such as are formed for 
indefatigable swimming or diving, or for wide flights over the 
deserts of ocean, we shall find them no less wonderfully or- 
ganised than the winged dwellers on the strand. Their short 
compressed toes easily cleave the waters, and by means of their 
membranes or webs form, as it were, broad oars. Their muscular 
Speckled Diver. 
short legs, placed more behind than in other birds, are beauti- 
fully adapted for rowing, although their movements on land 
are awkward and slow. All creatures living on the sea of course 
require a thick waterproof mantle against weather and storm ; 
and consequently we find the plumage of sea birds thicker, 
closer, and better furnished with down than that of the other 
feathered tribes. And finally, the gland which all birds have at 
the rump, and from which they express an oily matter to 
preserve their feathers moist, is most considerable among those 
that live upon the water, and contributes to make their plumage 
