84 DIVING BIRDS AT THE ZOO 
It launches itself on the surface and then “ ducks ” 
like a grebe. Its wings are not used as propellers, but 
trail unresistingly level with its body, and the speed at 
which it courses through the water is wholly due to 
the swimming powers of its large and ugly webbed 
feet. These are set on quite at the end of the body, 
and work incessantly like a treadle, or the floats of a 
stern-wheel steamer. Yet the conditions of submarine 
motion are so favourable, that the speed of the bird 
below the surface is three or four times greater than 
that gained by equally rapid movements of the feet 
when it has risen and is swimming on the top. The 
lustre of the feathers in the clear water, the cloud of 
brilliant bubbles which pour from the plumage, like 
the nebulous train of a comet, as the bird rushes 
through the water, and the sapphire light of the large 
blue eye, make the cormorant’s fishing one of the 
prettiest aquatic exercises in the world. 
The darters, though resembling the cormorant 
rather than the penguin in using their feet only for 
propulsion, are so clearly a survival of some ancient 
type, with their long snaky necks and pointed 
mandibles, and meagre membranous wings, that the 
imagination travels back at once to the steamy forests 
and swamps, and fish and saurian-haunted waters of 
some antediluvian epoch. The appearance of these 
creatures below water is even, stranger than when 
perched on the bank above. Like the cormorant 
they swim with the feet only, and with the same rapid 
mechanical alternate movements of each. Like the 
