FAMILY CHARACTERISTICS. 125 
swimming of the Frog,—the swift run of the 
Lizard, like a flash of green or red light in the 
sunshine, — the lateral undulation of the Ser- 
pent,—the dart of the Pickerel,—the leap of 
the Trout, — the rush of the Hawk-Moth through 
the air,—the fluttering flight of the Butterfly, 
—the quivering poise of the Humming-Bird, — 
the arrow-like shooting of the Squid through the 
water, — the slow crawling of the Snail on the 
land, — the sideway movement of the Sand-Crab, 
—the backward walk of the Crawfish, — the 
almost imperceptible gliding of the Sea-Anemone 
over the rock, — the graceful, rapid motion of the 
Pleurobrachia, with its endless change of curve 
and spiral. In short, every Family of animals 
has its characteristic action and its peculiar 
voice; and yet so little is this endless variety 
of rhythm and cadence both of motion and 
sound in the organic world understood, that we 
lack words to express one half its richness and 
beauty. 
