48 Introduction. 



their clumsiness is transformed into the greatest activity. To 

 enable them to move about on the water with such ease and 

 such celerity, they are supplied with legs and feet very much 

 resembling the paddles used in Indian canoes : their thighs are 

 placed very far back, in some instances almost at their tails ; 

 their legs are very flat and extremely thin, like the blade of an 

 oar ; their feet are broad and large, and completely webbed, the 

 toes connected together with membranes up to the nails ; with 

 these they strike the water with considerable force, and thus 

 their bodies are impelled forwards with speed ; and as the boat- 

 man, in rowing, feathers his oar after each successive stroke, 

 and in order to offer as small a surface as possible to the resist- 

 ance of the air and water, presents the thin knife-like edge of 

 the blade, while he draws it back for the next stroke, but while 

 pulling it through the water presents the broad blade as a means 

 of obtaining a good purchase for his pull just so is it with the 

 feet and legs of the swimming birds ; at every stroke the broad flat 

 leg and the expanded webbed foot give a hearty thrust ; but in 

 withdrawing them again, preparatory to repeating the thrust, the 

 thin edge of the leg is presented to the water, and the toes are 

 drawn together, and closely folded up, presenting as little resist- 

 ance as possible, till they are spread out again for the next 

 stroke. With these admirable provisions for moving at will on 

 the waves all the swimmers are supplied, but as some families are 

 more expert in the water, and less able to leave it for the shore 

 or the air than others, there are considerable variations in the 

 exact formations of their feet : thus, some have only three toes ; 

 others have four, but frequently three only are webbed, the 

 fourth remaining free, and articulated high up on the tarsus; 

 others again, have a pendant lobe or membrane, depending from 

 the hind toe, while some have all four toes completely webbed 

 together. According to these different formations, so their 

 powers of swimming and diving are increased or lessened ; but 

 all enjoy those faculties to a considerable extent. 



Such, then, are the general characters of the feet, as applicable 

 to the five orders. Though those of certain individual species 



